Before downgrading from MySQL 5.1, review the changes described in this section. Some changes may require action before or after downgrading.
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
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-eventsoption. (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.proctable 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.proccreated by mysqldump (such as when using the
--all-databasesoption). Instead, you should run mysqldump
--routinesprior 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
TRIGGERprivilege as of MySQL 5.1. In MySQL 5.0, there is no
SUPERis required instead. If you downgrade from MySQL 5.1 to 5.0, you will need to give the
SUPERprivilege to those accounts that had the
TRIGGERprivilege in 5.1.