Downgrading binary and package-based installations on Unix/Linux

Let’s learn how to downgrade binary and package-based installations on Unix or Linux. There are several ways to downgrade binary and package-based installations on Unix or Linux. They are discussed below.

In-place downgrade

• In-place downgrade involves shutting down the new MySQL version.

• After this operation is completed, the new MySQL binaries or packages will be replaced with the old binaries or packages.

• After completing this operation, the old MySQL version is restarted on the existing data directory.

• MySQL must be configured to perform a slow shutdown by setting innodb_fast_shutdown to 0.

The following command will perform the same operation -

mysql -u root -p --execute="SET GLOBAL innodb_fast_shutdown=0"

Shut down the newer MySQL server. This can be done using the following command -

mysqladmin -u root -p shutdown

After a slow shutdown, the InnoDB redo log files are deleted from the data directory (ib_logfile* files). This is done to avoid downgrade issues related to the redo log file format that occur between versions.

Logical Downgrade

• Logical downgrade involves using mysqldump to dump all tables in the new MySQL version.

• After completing this operation, the dump file will be loaded into the old MySQL version.

• Downgrade between versions within the same version supports logical downgrade Version series and downgrade to previous version levels.

• Only downgrades between General Availability (GA) releases are supported.

• Dump all databases. This is done using the following command -

mysqldump −u root −p
   −−add−drop−table −−routines −−events
   −−all−databases −−force > data−for−downgrade.sql

Shut down newer MySQL servers using the following command -

mysqladmin −u root −p shutdown

The above is the detailed content of Downgrading binary and package-based installations on Unix/Linux. For more information, please follow other related articles on the PHP Chinese website!