Bug #4502 mysqld crashes when executing convert to on columns_priv table e.t.c.
Submitted: 10 Jul 2004 15:56 Modified: 13 Jul 2004 12:06
Reporter: Stepan Yakovlev Email Updates:
Status: Not a Bug Impact on me:
None 
Category:MySQL Server: MyISAM storage engine Severity:S2 (Serious)
Version:4.1.3 beta-nt OS:Microsoft Windows (Windows XP SP 1a)
Assigned to: CPU Architecture:Any

[10 Jul 2004 15:56] Stepan Yakovlev
Description:
Using default charset utf, collation utf8_unicode_ci
When trying to convert tables to utf8_unicode_ci collation (before was using general_ci now migrating) database has large number of tables, so written small script to get all tables with SHOW TABLES and execute convert on each table. previously tables charset utf8  collation utf8_general_ci

alter table tbale_name convert to character set utf-8 collate utf8_unicode_ci;

mysqld immediately crashes, when trying to update table columns_priv , tables_priv... may be it's not necessary, but with large number of tables i didn't sorted them to remove system tables

How to repeat:
alter table tbale_name convert to character set utf-8 collate utf8_unicode_ci;

Suggested fix:
Don't know. I'm web developer, not db programmer
[10 Jul 2004 15:59] Stepan Yakovlev
sorry how to repeat:

alter table columns_priv convert to character set utf8 collate utf8_unicode_ci;
[13 Jul 2004 12:06] Hartmut Holzgraefe
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.mysql.com/documentation/ and the instructions on
how to report a bug at http://bugs.mysql.com/how-to-report.php

Additional info:

http://dev.mysql.com/doc/mysql/en/Converting_tables_to_InnoDB.html:

"Important: You should not convert MySQL system tables in the mysql database (such as user or host) to the InnoDB type. The system tables must always be of the MyISAM type."

The same applies to the system tables charsets. You should never change these
as the server heavily relies on the internal representation of the system tables.