WSREP_INFO Plugin

The WSREP_INFO plugin library contains the following plugins:

• WSREP_MEMBERSHIP
• WSREP_STATUS

The WSREP_MEMBERSHIP plugin creates the WSREP_MEMBERSHIP table in the INFORMATION_SCHEMA database. The plugin also adds the SHOW WSREP_MEMBERSHIP statement.

The WSREP_STATUS plugin creates the WSREP_STATUS table in the INFORMATION_SCHEMA database. The plugin also adds the SHOW WSREP_STATUS statement.

These tables and statements provide information about Galera. Only users with the SUPER privilege can access this information.

Installing the Plugin

Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB.

The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing INSTALL SONAME or INSTALL PLUGIN. For example:

INSTALL SONAME 'wsrep_info';

The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the --plugin-load or the --plugin-load-add options. This can be specified as a command-line argument to mysqld or it can be specified in a relevant server option group in an option file. For example:

[mariadb]
...
plugin_load_add = wsrep_info

Uninstalling the Plugin

You can uninstall the plugin dynamically by executing UNINSTALL SONAME or UNINSTALL PLUGIN. For example:

UNINSTALL SONAME 'wsrep_info';

If you installed the plugin by providing the --plugin-load or the --plugin-load-add options in a relevant server option group in an option file, then those options should be removed to prevent the plugin from being loaded the next time the server is restarted.

Example

SHOW TABLES FROM information_schema LIKE 'WSREP%';
+---------------------------------------+
| Tables_in_information_schema (WSREP%) |
+---------------------------------------+
| WSREP_STATUS                          |
| WSREP_MEMBERSHIP                      |
+---------------------------------------+

Versions

Options

wsrep_membership

• Description: Controls how the server should treat the plugin when the server starts up.
  • Valid values are:
    • OFF - Disables the plugin without removing it from the mysql.plugins table.
    • ON - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled.
    • FORCE - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error.
    • FORCE_PLUS_PERMANENT - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with UNINSTALL SONAME or UNINSTALL PLUGIN while the server is running.
  • See Plugin Overview: Configuring Plugin Activation at Server Startup for more information.
• Commandline: --wsrep-membership=value
• Data Type: enumerated
• Default Value: ON
• Valid Values: OFF, ON, FORCE, FORCE_PLUS_PERMANENT

wsrep_status

• Description: Controls how the server should treat the plugin when the server starts up.
  • Valid values are:
    • OFF - Disables the plugin without removing it from the mysql.plugins table.
    • ON - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled.
    • FORCE - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error.
    • FORCE_PLUS_PERMANENT - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with UNINSTALL SONAME or UNINSTALL PLUGIN while the server is running.
  • See Plugin Overview: Configuring Plugin Activation at Server Startup for more information.
• Commandline: --wsrep-status=value
• Data Type: enumerated
• Default Value: ON
• Valid Values: OFF, ON, FORCE, FORCE_PLUS_PERMANENT