MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

5.5 MySQL Server Components

MySQL Server includes a component-based infrastructure for extending server capabilities. A component provides services that are available to the server and other components. (With respect to service use, the server is a component, equal to other components.) Components interact with each other only through the services they provide.

MySQL distributions include several components that implement server extensions:

System and status variables implemented by a server component are exposed when the component is installed and have names that begin with a component-specific prefix. For example, the log_filter_dragnet error log filter component implements a system variable named log_error_filter_rules, the full name of which is dragnet.log_error_filter_rules. To refer to this variable, use the full name.

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

For information about the internal implementation of components, see the MySQL Server Doxygen documentation, available at For example, if you intend to write your own components, this information is important for understanding how components work.