set global event_scheduler=off;
drop database if exists events_test;
create database events_test;
use events_test;
create table execution_log(name char(10));
create event abc1 on schedule every 1 second do
insert into execution_log value('abc1');
create event abc2 on schedule every 1 second do
insert into execution_log value('abc2');
create event abc3 on schedule every 1 second do 
insert into execution_log value('abc3');
create table event_like like mysql.event;
insert into event_like select * from mysql.event;
alter table mysql.event
change column body  body longtext character set utf8 collate utf8_bin;
"Now we restart the server"
use events_test;
select @@event_scheduler;
@@event_scheduler
DISABLED
show events;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
select event_name from information_schema.events;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
show create event intact_check;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
drop event no_such_event;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
create event intact_check_1 on schedule every 5 hour do select 5;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
alter event intact_check_1 on schedule every 8 hour do select 8;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
alter event intact_check_1 rename to intact_check_2;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
drop event intact_check_1;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
drop event intact_check_2;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
drop event intact_check;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
set global event_scheduler=on;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
set global event_scheduler=off;
ERROR HY000: Cannot proceed because system tables used by Event Scheduler were found damaged at server start
show variables like 'event_scheduler';
Variable_name	Value
event_scheduler	DISABLED
Make sure that we still can create and drop databases,
and no warnings are produced.
drop database if exists mysqltest_database_not_exists;
Warnings:
Note	1008	Can't drop database 'mysqltest_database_not_exists'; database doesn't exist
create database mysqltest_db1;
drop database mysqltest_db1;
Restore the original mysql.event table
drop table mysql.event;
rename table event_like to mysql.event;
Now let's restart the server again
use events_test;
select @@event_scheduler;
@@event_scheduler
ON
drop table execution_log;
drop database events_test;