2.7. Migrating to MariaDB 10.5

• MariaDB now uses the unix_socket authentication plug-in by default. The plug-in enables users to use operating system credentials when connecting to MariaDB through the local UNIX socket file.
• MariaDB adds mariadb-* named binaries and mysql* symbolic links pointing to the mariadb-* binaires. For example, the mysqladmin, mysqlaccess, and mysqlshow symlinks point to the mariadb-admin, mariadb-access, and mariadb-show binaries, respectively.
• The SUPER privilege has been split into several privileges to better align with each user role. As a result, certain statements have changed required privileges.
• In parallel replication, the slave_parallel_mode now defaults to optimistic.
• In the InnoDB storage engine, defaults of the following variables have been changed: innodb_adaptive_hash_index to OFF and innodb_checksum_algorithm to full_crc32.

• MariaDB now uses the libedit implementation of the underlying software managing the MariaDB command history (the .mysql_history file) instead of the previously used readline library. This change impacts users working directly with the .mysql_history file. Note that .mysql_history is a file managed by the MariaDB or MySQL applications, and users should not work with the file directly. The human-readable appearance is coincidental.

  Note

  To increase security, you can consider not maintaining a history file. To disable the command history recording:

  1. Remove the .mysql_history file if it exists.

  2. Use either of the following approaches:

     • Set the MYSQL_HISTFILE variable to /dev/null and include this setting in any of your shell’s startup files.

     • Change the .mysql_history file to a symbolic link to /dev/null:

       $ ln -s /dev/null $HOME/.mysql_history

• Galera adds a new streaming replication feature, which supports replicating transactions of unlimited size. During an execution of streaming replication, a cluster replicates a transaction in small fragments.
• Galera now fully supports Global Transaction ID (GTID).
• The default value for the wsrep_on option in the /etc/my.cnf.d/galera.cnf file has changed from 1 to 0 to prevent end users from starting wsrep replication without configuring required additional options.

• MariaDB 10.5 adds a new version of the Pluggable Authentication Modules (PAM) plug-in. The PAM plug-in version 2.0 performs PAM authentication using a separate setuid root helper binary, which enables MariaDB to use additional PAM modules.
• The helper binary can be executed only by users in the mysql group. By default, the group contains only the mysql user. Red Hat recommends that administrators do not add more users to the mysql group to prevent password-guessing attacks without throttling or logging through this helper utility.
• In MariaDB 10.5, the Pluggable Authentication Modules (PAM) plug-in and its related files have been moved to a new package, mariadb-pam. As a result, no new setuid root binary is introduced on systems that do not use PAM authentication for MariaDB.
• The mariadb-pam package contains both PAM plug-in versions: version 2.0 is the default, and version 1.0 is available as the auth_pam_v1 shared object library.
• The mariadb-pam package is not installed by default with the MariaDB server. To make the PAM authentication plug-in available in MariaDB 10.5, install the mariadb-pam package manually.

Conditions préalables

• Before performing the upgrade, back up all your data stored in the MariaDB databases.