Upgrading MariaDB MaxScale from 2.3 to 2.4

This document describes possible issues when upgrading MariaDB MaxScale from version 2.3 to 2.4.

For more information about MariaDB MaxScale 2.4, please refer to the ChangeLog.

Before starting the upgrade, we recommend you back up your current configuration file.

Section Names

Reserved Names

Section and object names starting with @@ are now reserved for internal use by MaxScale.

In case such names have been used, they must manually be changed in all configuration files of MaxScale, before MaxScale 2.4 is started.

Those files are:

• The main configuration file; typically /etc/maxscale.cnf.
• All nested configuration files; typically /etc/maxscale.cnf.d/*.
• All dynamic configuration files; typically /var/lib/maxscale/maxscale.cnd.d/*.

Whitespace in Names

Whitespace in section names that was deprecated in MaxScale 2.2 will now be rejected, which will cause the startup of MaxScale to fail.

To prevent that, section names like

[My Server]
...

[My Service]
...
servers=My Server

must be changed, for instance, to

[MyServer]
...

[MyService]
...
servers=MyServer

Durations

Durations can now be specified using one of the suffixes h, m, s and ms for specifying durations in hours, minutes, seconds and milliseconds, respectively.

Not providing an explicit unit has been deprecated in MaxScale 2.4, so it is adviseable to add suffixes to durations. For instance,

some_param=60s
some_param=60000ms

Improved Admin User Encryption

MaxScale 2.4 will use a SHA2-512 hash for new admin user passwords. To upgrade a user to use the better hashing algorithm, either recreate the user or use the maxctrl alter user command.

MariaDB-Monitor

The following settings have been removed and cause a startup error if defined:

• mysql51_replication
• multimaster
• allow_cluster_recovery.

ReadWriteSplit

• If multiple masters are available for a readwritesplit service, the one with the lowest connection count is selected.

• If a master server is placed into maintenance mode, all open transactions are allowed to gracefully finish before the session is closed. To forcefully close the connections, use the --force option for maxctrl set server.

• The lazy_connect feature can be used as a workaround to MXS-619. It also reduces the overall load on the system when connections are rapidly opened and closed.

• Transaction replays now have a limit on how many times a replay is attempted. The default values is five attempts and is controlled by the transaction_replay_attempts parameter.

• If transaction replay is enabled and a deadlock occurs (SQLSTATE 40XXX), the transaction is automatically retried.