5.5.1 Installing and Uninstalling Plugins
Server plugins must be loaded into the server before they can be used. MySQL supports plugin loading at server startup and runtime. It is also possible to control the activation state of loaded plugins at startup, and to unload them at runtime.
While a plugin is loaded, information about it is available from the
INFORMATION_SCHEMA.PLUGINS table and the
SHOW PLUGINS statement. See Section 5.5.2, “Obtaining Server Plugin Information”.
Before a server plugin can be used, it must be installed using one of the following methods. In the descriptions,
plugin_name stands for a plugin name such as
A built-in plugin is known by the server automatically. Normally, the server enables the plugin at startup. Some built-in plugins permit this to be changed with the
plugin table in the
mysql system database serves as a registry of plugins (other than built-in plugins, which need not be registered). At startup, the server loads each plugin listed in the table. Normally, for a plugin loaded from the
mysql.plugin table, the server also enables the plugin. This can be changed with the
If the server is started with the
--skip-grant-tables option, it does not consult the
mysql.plugin table and does not load the plugins listed there.
A plugin located in a plugin library file can be loaded at server startup with the
--plugin-load-add, or (as of MySQL 5.7.11)
--early-plugin-load option. Normally, for a plugin loaded at startup, the server also enables the plugin. This can be changed with the
--plugin-load-add options load plugins after built-in plugins and storage engines have initialized during the server startup sequence. The
--early-plugin-load option is used to load plugins that must be available prior to initialization of built-in plugins and storage engines.
The value of each plugin-loading option is a semicolon-separated list of
plugin_library values. Each
name is the name of a plugin to load, and
plugin_library is the name of the library file that contains the plugin code. If a plugin library is named without any preceding plugin name, the server loads all plugins in the library. The server looks for plugin library files in the directory named by the
plugin_dir system variable.
Plugin-loading options do not register any plugin in the
mysql.plugin table. For subsequent restarts, the server loads the plugin again only if
--early-plugin-load is given again. That is, the option produces a one-time plugin-installation operation that persists for a single server invocation.
--early-plugin-load enable plugins to be loaded even when
--skip-grant-tables is given (which causes the server to ignore the
--early-plugin-load also enable plugins to be loaded at startup that cannot be loaded at runtime.
Each instance of
--plugin-loadresets the set of plugins to load at startup, whereas
--plugin-load-addadds a plugin or plugins to the set of plugins to be loaded without resetting the current set. Consequently, if multiple instances of
--plugin-loadare specified, only the last one takes effect. With multiple instances of
--plugin-load-add, all of them take effect.
The argument format is the same as for
--plugin-load, but multiple instances of
--plugin-load-addcan be used to avoid specifying a large set of plugins as a single long unwieldy
--plugin-load-addcan be given in the absence of
--plugin-load, but any instance of
--plugin-load-addthat appears before
--plugin-loadhas no effect because
--plugin-loadresets the set of plugins to load.
For example, these options:
are equivalent to this option:
But these options:
are equivalent to this option:
A plugin located in a plugin library file can be loaded at runtime with the
INSTALL PLUGIN statement. The statement also registers the plugin in the
mysql.plugin table to cause the server to load it on subsequent restarts. For this reason,
INSTALL PLUGIN requires the
INSERT privilege for the
The plugin library file base name depends on your platform. Common suffixes are
.so for Unix and Unix-like systems,
.dll for Windows.
--plugin-load option installs a plugin at server startup. To install a plugin named
myplugin from a plugin library file named
somepluglib.so, use these lines in a
In this case, the plugin is not registered in
mysql.plugin. Restarting the server without the
--plugin-load option causes the plugin not to be loaded at startup.
INSTALL PLUGIN statement causes the server to load the plugin code from the library file at runtime:
INSTALL PLUGIN myplugin SONAME 'somepluglib.so';
INSTALL PLUGIN also causes “permanent” plugin registration: The plugin is listed in the
mysql.plugin table to ensure that the server loads it on subsequent restarts.
Many plugins can be loaded either at server startup or at runtime. However, if a plugin is designed such that it must be loaded and initialized during server startup, attempts to load it at runtime using
INSTALL PLUGIN produce an error:
mysql> INSTALL PLUGIN myplugin SONAME 'somepluglib.so'; ERROR 1721 (HY000): Plugin 'myplugin' is marked as not dynamically installable. You have to stop the server to install it.
If a plugin is named both using a
--early-plugin-load option and (as a result of an earlier
INSTALL PLUGIN statement) in the
mysql.plugin table, the server starts but writes these messages to the error log:
[ERROR] Function 'plugin_name' already exists [Warning] Couldn't load plugin named 'plugin_name' with soname 'plugin_object_file'.
If the server knows about a plugin when it starts (for example, because the plugin is named using a
--plugin-load option or is registered in the
mysql.plugin table), the server loads and enables the plugin by default. It is possible to control activation state for such a plugin using a
-- startup option, where
plugin_name is the name of the plugin to affect, such as
validate_password. As with other options, dashes and underscores are interchangeable in option names. Also, activation state values are not case-sensitive. For example,
--my-plugin=on are equivalent.
Tells the server to disable the plugin. This may not be possible for certain built-in plugins, such as
Tells the server to enable the plugin. (Specifying the option as
--without a value has the same effect.) If the plugin fails to initialize, the server runs with the plugin disabled.
Tells the server to enable the plugin, but if plugin initialization fails, the server does not start. In other words, this option forces the server to run with the plugin enabled or not at all.
FORCE, but in addition prevents the plugin from being unloaded at runtime. If a user attempts to do so with
UNINSTALL PLUGIN, an error occurs.
Plugin activation states are visible in the
LOAD_OPTION column of the
ARCHIVE are built-in pluggable storage engines and that you want the server to load them at startup, subject to these conditions: The server is permitted to run if
CSV initialization fails, must require that
BLACKHOLE initialization succeeds, and should disable
ARCHIVE. To accomplish that, use these lines in an option file:
[mysqld] csv=ON blackhole=FORCE archive=OFF
--enable- option format is a synonym for
--skip- option formats are synonyms for
If a plugin is disabled, either explicitly with
OFF or implicitly because it was enabled with
ON but fails to initialize, aspects of server operation that require the plugin will change. For example, if the plugin implements a storage engine, existing tables for the storage engine become inaccessible, and attempts to create new tables for the storage engine result in tables that use the default storage engine unless the
NO_ENGINE_SUBSTITUTION SQL mode is enabled to cause an error to occur instead.
Disabling a plugin may require adjustment to other options. For example, if you start the server using
--skip-innodb to disable
innodb_ options likely will need to be omitted at startup. In addition, because
InnoDB is the default storage engine, it will not start unless you specify another available storage engine with
--default_storage_engine. You must also set
At runtime, the
UNINSTALL PLUGIN statement disables and uninstalls a plugin known to the server. The statement unloads the plugin and removes it from the
mysql.plugin system table, if it is registered there. For this reason,
UNINSTALL PLUGIN statement requires the
DELETE privilege for the
mysql.plugin table. With the plugin no longer registered in the table, the server does not load the plugin automatically for subsequent restarts.
It cannot unload plugins for which the server was started with
--, which prevents plugin unloading at runtime. These can be identified from the
LOAD_OPTIONcolumn of the
To uninstall a plugin that currently is loaded at server startup with a plugin-loading option, use this procedure.
Remove from the
my.cnffile any options related to the plugin.
Restart the server.
Plugins normally are installed using either a plugin-loading option at startup or with
INSTALL PLUGINat runtime, but not both. However, removing options for a plugin from the
my.cnffile may not be sufficient to uninstall it if at some point
INSTALL PLUGINhas also been used. If the plugin still appears in the output from
SHOW PLUGINS, use
UNINSTALL PLUGINto remove it from the
mysql.plugintable. Then restart the server again.