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MySQL 8.4 Reference Manual  /  MySQL Server Administration  /  MySQL Server Loadable Functions

7.7 MySQL Server Loadable Functions

MySQL supports loadable functions, that is, functions that are not built in but can be loaded at runtime (either during startup or later) to extend server capabilities, or unloaded to remove capabilities. For a table describing the available loadable functions, see Section 14.2, “Loadable Function Reference”. Loadable functions contrast with built-in (native) functions, which are implemented as part of the server and are always available; for a table, see Section 14.1, “Built-In Function and Operator Reference”.


Loadable functions previously were known as user-defined functions (UDFs). That terminology was something of a misnomer because user-defined also can apply to other types of functions, such as stored functions (a type of stored object written using SQL) and native functions added by modifying the server source code.

MySQL distributions include loadable functions that implement, in whole or in part, these server capabilities:

The following sections describe how to install and uninstall loadable functions, and how to determine at runtime which loadable functions are installed and obtain information about them.

In some cases, a loadable function is loaded by installing the component that implements the function, rather than by loading the function directly. For details about a particular loadable function, see the installation instructions for the server feature that includes it.

For information about writing loadable functions, see Adding Functions to MySQL.