MySQL 5.1 and up supports a plugin API that allows the loading and unloading of server components at runtime, without restarting the server. The API is generic and does not specify what plugins can do. The components supported by this interface include, but are not limited to, full-text parser plugins, storage-engines and server extensions. In MySQL 5.1, the storage engines can be included in the server as plugins.

Full-text parser plugins can be used to replace or augment the built-in full-text parser. For example, a plugin can parse text into words using rules that differ from those used by the built-in parser. This can be useful if you need to parse text with characteristics different from those expected by the built-in parser.

The plugin interface is intended as the successor to the older user-defined function (UDF) interface.

The plugin interface uses the plugin table in the mysql database to record information about plugins. This table is created as part of the MySQL installation process. If you are upgrading from a version of MySQL older than 5.1, you should run the mysql_upgrade command to create this table. See Section 4.4.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.