6.7.1. Upgrading Replication to 5.0
This section applies to upgrading replication from MySQL 3.23,
4.0, or 4.1 to MySQL 5.1. A 4.0 server should be
4.0.3 or newer.
When you upgrade a master to 5.1 from an earlier
MySQL release series, you should first ensure that all the
slaves of this master are using the same 5.1.x
release. If this is not the case, you should first upgrade the
slaves. To upgrade each slave, shut it down, upgrade it to the
appropriate 5.1.x version, restart it, and restart
replication. The 5.1 slave is able to read the old
relay logs written prior to the upgrade and to execute the
statements they contain. Relay logs created by the slave after
the upgrade are in 5.1 format.
After the slaves have been upgraded, shut down the master,
upgrade it to the same 5.1.x release as the slaves,
and restart it. The 5.1 master is able to read the
old binary logs written prior to the upgrade and to send them to
the 5.1 slaves. The slaves recognize the old format
and handle it properly. Binary logs created by the master
following the upgrade are in 5.1 format. These too
are recognized by the 5.1 slaves.
In other words, there are no measures to take when upgrading to
MySQL 5.1, except that the slaves must be MySQL
5.1 before you can upgrade the master to
5.1. Note that downgrading from 5.1 to
older versions does not work so simply: You must ensure that any
5.1 binary logs or relay logs have been fully
processed, so that you can remove them before proceeding with
the downgrade.
Downgrading a replication setup to a previous version cannot be
done once you've switched from statement-based to row-based
replication, and after the first row-based statement has been
written to the binlog. See
Section 6.3, “Row-Based Replication”.
