This section compares the various methods of installing and uninstalling server plugins.
INSTALL PLUGIN statement:
Loads the plugin code to activate it.
Registers the plugin in the
mysql.plugintable. Registration causes the server to load the plugin automatically for subsequent restarts. That is, it effects an installation that persists until the plugin is uninstalled explicitly.Requires the
INSERTprivilege for themysql.plugintable.
--plugin-load option:
Loads the plugin code to activate it.
Does not register the plugin in
mysql.plugin. For subsequent restarts, the server loads the plugin again only if--plugin-loadis given again. That is, this option effects a one-time installation that persists only for one server invocation.
UNINSTALL PLUGIN statement:
Unloads the plugin code to deactivate it.
Unregisters the plugin from
mysql.plugin. The server will not load it automatically for subsequent restarts.Requires the
DELETEprivilege for themysql.plugintable.
While a plugin is loaded, information about it is available at runtime from these sources:
The
INFORMATION_SCHEMA.PLUGINStableThe
SHOW PLUGINSstatementThe
mysql.plugintable (if the plugin was installed withINSTALL PLUGIN)
If --plugin-load is given at
startup for a plugin already installed with
INSTALL PLUGIN during a previous
server invocation, the server starts but writes these messages
to the error log:
100310 19:15:44 [ERROR] Function 'plugin_name' already exists 100310 19:15:44 [Warning] Couldn't load plugin named 'plugin_name' with soname 'plugin_object_file'.
UNINSTALL PLUGIN can unload
plugins regardless of whether they were loaded with
INSTALL PLUGIN or
--plugin-load. In the latter
case, UNINSTALL PLUGIN does not
unregister the plugin from mysql.plugin
because --plugin-load did not
register it.
UNINSTALL PLUGIN cannot unload
plugins that are compiled into the server. (These can be
identified as those that have a library name of
NULL in the output from
INFORMATION_SCHEMA.PLUGINS or
SHOW PLUGINS.)
If the server is started with the
--skip-grant-tables option, it
does not consult the mysql.plugins table and
thus does not load plugins installed with the
INSTALL PLUGIN statement.
--plugin-load enables plugins to
be loaded even when
--skip-grant-tables is given.
--plugin-load also enables
plugins to be loaded at startup under configurations when
plugins cannot be loaded at runtime.