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2.4.3 Checking Whether Tables or Indexes Must Be Rebuilt »
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2.4.2.1. Downgrading to MySQL 5.0

When downgrading to MySQL 5.0 from MySQL 5.1, you should keep in mind the following issues relating to features found in MySQL 5.1, but not in MySQL 5.0:

  • Partitioning.  MySQL 5.0 does not support user-defined partitioning. If a table was created as a partitioned table in 5.1 (or if an table created in a previous version of MySQL was altered to include partitions after an upgrade to 5.1), the table is accessible after downgrade only if you do one of the following:

    • Export the table using mysqldump and then drop it in MySQL 5.1; import the table again following the downgrade to MySQL 5.0.

    • Prior to the downgrade, remove the table's partitioning using ALTER TABLE table_name REMOVE PARTITIONING.

  • Event Scheduler.  MySQL 5.0 does not support scheduled events. If your databases contain scheduled event definitions, you should prevent them from being dumped when you use mysqldump by using the --skip-events option. (See Section 4.5.4, “mysqldump — A Database Backup Program”.)

  • Stored routines.  MySQL 5.1.21 added a number of new columns to the mysql.proc table in which stored routine definitions are stored. If you are downgrading from MySQL 5.1.21 or later to MySQL 5.0, you cannot import the MySQL 5.1 routine definitions into MySQL 5.0.46 or earlier using the dump of mysql.proc created by mysqldump (such as when using the --all-databases option). Instead, you should run mysqldump --routines prior to performing the downgrade and run the stored routines DDL statements following the downgrade.

    See Bug#11986, Bug#30029, and Bug#30660, for more information.

  • Triggers.  Trigger creation requires the TRIGGER privilege as of MySQL 5.1. In MySQL 5.0, there is no TRIGGER privilege and SUPER is required instead. If you downgrade from MySQL 5.1 to 5.0, you will need to give the SUPER privilege to those accounts that had the TRIGGER privilege in 5.1.