Plugin Overview

Plugins are server components that enhance MariaDB in some way. These can be anything from new storage engines, plugins for enhancing full-text parsing, or even small enhancements, such as a plugin to get a timestamp as an integer.

Viewing plugin information

There are a number of ways to see which plugins are currently active. Note that there are a large number of plugins that are built-in and active by default, and which cannot be removed from the server.

The SHOW PLUGINS statement will list all active plugins.

SHOW PLUGINS;

+----------------------------+----------+--------------------+---------+---------+
| Name                       | Status   | Type               | Library | License |
+----------------------------+----------+--------------------+---------+---------+
...
| mysql_native_password      | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |
| mysql_old_password         | ACTIVE   | AUTHENTICATION     | NULL    | GPL     |
| MRG_MyISAM                 | ACTIVE   | STORAGE ENGINE     | NULL    | GPL     |
...
+----------------------------+----------+--------------------+---------+---------+

Plugins with the Library listed as NULL are built-in and cannot be uninstalled.

More detailed information can be retrieved by querying the INFORMATION_SCHEMA.PLUGINS table.

SELECT * FROM information_schema.PLUGINS\G
...
*************************** 6. row ***************************
           PLUGIN_NAME: CSV
        PLUGIN_VERSION: 1.0
         PLUGIN_STATUS: ACTIVE
           PLUGIN_TYPE: STORAGE ENGINE
   PLUGIN_TYPE_VERSION: 100003.0
        PLUGIN_LIBRARY: NULL
PLUGIN_LIBRARY_VERSION: NULL
         PLUGIN_AUTHOR: Brian Aker, MySQL AB
    PLUGIN_DESCRIPTION: CSV storage engine
        PLUGIN_LICENSE: GPL
           LOAD_OPTION: FORCE
       PLUGIN_MATURITY: Stable
   PLUGIN_AUTH_VERSION: 1.0
*************************** 7. row ***************************
           PLUGIN_NAME: MEMORY
        PLUGIN_VERSION: 1.0
         PLUGIN_STATUS: ACTIVE
           PLUGIN_TYPE: STORAGE ENGINE
   PLUGIN_TYPE_VERSION: 100003.0
        PLUGIN_LIBRARY: NULL
PLUGIN_LIBRARY_VERSION: NULL
         PLUGIN_AUTHOR: MySQL AB
    PLUGIN_DESCRIPTION: Hash based, stored in memory, useful for temporary tables
        PLUGIN_LICENSE: GPL
           LOAD_OPTION: FORCE
       PLUGIN_MATURITY: Stable
   PLUGIN_AUTH_VERSION: 1.0
...

Here, if the PLUGIN_LIBRARY is NULL, the plugin is built-in and cannot be uninstalled.

Finally, you can query the mysql.plugin table. This table only contains plugins that have been loaded with INSTALL SONAME, INSTALL PLUGIN or the mysql_plugin utility, not built-in plugins, or plugins loaded with the --plugin-load option. It also contains much less information, just the name and library.

SELECT * FROM mysql.plugin;

+------+------------+
| name | dl         |
+------+------------+
| PBXT | libpbxt.so |
+------+------------+

Installing Plugins

Plugins can be installed in three ways:

• With the INSTALL SONAME or the INSTALL PLUGIN statement when the server is running
• With the --plugin-load or (since 10.0) --plugin-load-add mysqld option when the server starts.
• With the mysql_plugin utility when the server is offline.

The --plugin-load option takes a semicolon-separated list of plugins to load, where each plugin is identified as name=library, where name is the plugin name and library is the plugin library in the plugin directory, specified by the plugin_dir system variable.

--plugin-load does not add records to the mysql.plugins table, so if the server is restarted without the same --plugin-load options, those plugins not listed will not be loaded.

Plugins installed with INSTALL SONAME, INSTALL PLUGIN or mysql_plugin will automatically be loaded the next time the server starts, unless specifically uninstalled, or deactivated, as described below. The difference between these statements is that INSTALL PLUGIN installs a single plugin from a given library, while INSTALL SONAME installs all plugins from the given library (which could be required).

Controlling Plugin Activation

Plugins that are listed in the mysql.plugin table, or listed as a --plugin-load option, will by default be loaded. This behavior can be changed, with --plugin-name options.

The plugin status is listed in the PLUGIN_STATUS field of the INFORMATION_SCHEMA.PLUGINS table.

Uninstalling Plugins

Plugins that are found in the mysql.plugin table, that is those that were installed with INSTALL SONAME, INSTALL PLUGIN or mysql_plugin can be uninstalled in one of two ways:

• The UNINSTALL SONAME or the UNINSTALL PLUGIN statement while the server is running
• With mysql_plugin while the server is offline.

Plugins that were enabled as a --plugin-load option do not need to be uninstalled. If --plugin-load is omitted the next time the server starts, or the plugin is not listed as one of the --plugin-load entries, the plugin will not be loaded.

UNINSTALL PLUGIN uninstalls a single installed plugin, while UNINSTALL SONAME uninstalls all plugins belonging to a given library.