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 a Plugin

There are three primary ways to install a plugin:

• A plugin can be installed dynamically with an SQL statement.
• A plugin can be installed with a mysqld option, but it requires a server restart.
• A plugin can be installed with the mysql_plugin utility, while the server is completely offline.

Installing a Plugin Dynamically

A plugin can be installed dynamically by executing either the INSTALL SONAME or the INSTALL PLUGIN statement.

If a plugin is installed with one of these statements, then a record will be added to the mysql.plugins table for the plugin. This means that the plugin will automatically be loaded every time the server restarts, unless specifically uninstalled or deactivated.

Installing a Plugin with INSTALL SONAME

You can install a plugin dynamically by executing the INSTALL SONAME statement. For example:

INSTALL SONAME 'server_audit';

INSTALL SONAME installs all plugins from the given library. This could be required for some plugin libraries.

Installing a Plugin with INSTALL PLUGIN

You can install a plugin dynamically by executing the INSTALL PLUGIN statement. For example:

INSTALL PLUGIN server_audit SONAME 'server_audit';

INSTALL PLUGIN installs a single plugin from the given library

Installing a Plugin with an Option

A plugin can be installed with a mysqld option by providing either the --plugin-load-add or the --plugin-load option.

If a plugin is installed with one of these options, then a record will not be added to the mysql.plugins table for the plugin. This means that if the server is restarted without the same option set, then the plugin will not automatically be loaded.

Installing a Plugin with --plugin-load-add

You can install a plugin with the --plugin-load-add option by specifying the option as a command-line argument to mysqld or by specifying the option in a relevant server option group in an option file.

The --plugin-load-add option uses the following format:

• Plugins can be specified in the format name=library, where name is the plugin name and library is the plugin library. This format installs a single plugin from the given library.
• Plugins can also be specified in the format library, where library is the plugin library. This format installs all plugins from the given library.
• Multiple plugins can be specified by separating them with semicolons.

For example, on the command-line:

$ mysqld --user=mysql --plugin-load-add='server_audit' --plugin-load-add='ed25519=auth_ed25519'

Or in an option file:

[mariadb]
...
plugin_load_add = server_audit
plugin_load_add = ed25519=auth_ed25519

Installing a Plugin with --plugin-load

You can install a plugin with the --plugin-load option by specifying the option as a command-line argument to mysqld or by specifying the option in a relevant server option group in an option file.

The --plugin-load option uses the following format:

• Plugins can be specified in the format name=library, where name is the plugin name and library is the plugin library. This format installs a single plugin from the given library.
• Plugins can also be specified in the format library, where library is the plugin library. This format installs all plugins from the given library.
• Multiple plugins can be specified by separating them with semicolons.

For example, on the command-line:

$ mysqld --user=mysql --plugin-load='server_audit;ed25519=auth_ed25519'

Or in an option file:

[mariadb]
...
plugin_load = server_audit;ed25519=auth_ed25519

Specifying Multiple Plugin Load Options

Special care must be taken when specifying the --plugin-load option multiple times, or when specifying both the --plugin-load option and the --plugin-load-add option. The --plugin-load option resets the plugin load list, and this can cause unexpected problems if you are not aware. The --plugin-load-add option does not reset the plugin load list, so it is much safer to use.

This can have the following consequences:

• If the --plugin-load option is specified multiple times, then only the last instance will have any effect. For example, in the following case, the first instance of the option is reset:

[mariadb]
...
plugin_load = server_audit
plugin_load = ed25519=auth_ed25519

• If the --plugin-load option is specified after the --plugin-load-add option, then it will also reset the changes made by that option. For example, in the following case, the --plugin-load-add option does not do anything, because the subsequent --plugin-load option resets the plugin load list:

[mariadb]
...
plugin_load_add = server_audit
plugin_load = ed25519=auth_ed25519

• In contrast, if the --plugin-load option is specified before the --plugin-load-add option, then it will work fine, because the --plugin-load-add option does not reset the plugin load list. For example, in the following case, both plugins are properly loaded:

[mariadb]
...
plugin_load = server_audit
plugin_load_add = ed25519=auth_ed25519

Installing a Plugin with mysql_plugin

A plugin can be installed with the mysql_plugin utility if the server is completely offline.

The syntax is:

mysql_plugin [options] <plugin> ENABLE|DISABLE

For example:

mysql_plugin server_audit ENABLE

If a plugin is installed with this utility, then a record will be added to the mysql.plugins table for the plugin. This means that the plugin will automatically be loaded every time the server restarts, unless specifically uninstalled or deactivated.

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.

See Also

• List of Plugins
• INSTALL PLUGIN
• INSTALL SONAME
• UNINSTALL PLUGIN
• UNINSTALL SONAME
• SHOW PLUGINS
• INFORMATION_SCHEMA.PLUGINS Table
• mysql_plugin