Installing and Uninstalling Components 1069 5.5.1 Installing and Uninstalling Components System and status variables implemented by a 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 https://dev.mysql.com/doc/index-other.html. For example, if you intend to write your own components, this information is important for understanding how components work. Components must be loaded into the server before they can be used. MySQL supports manual component loading at runtime and automatic loading during server startup. While a component is loaded, information about it is available as described in Section 5.5.2, “Obtaining Component Information” . The  INSTALL COMPONENT  and  UNINSTALL COMPONENT  SQL statements enable component loading and unloading. For example: INSTALL COMPONENT ’file://component_validate_password’; UNINSTALL COMPONENT ’file://component_validate_password’; A loader service handles component loading and unloading, and also registers loaded components in the mysql.component  system table. The SQL statements for component manipulation affect server operation and the  mysql.component system table as follows: Compared to the corresponding  INSTALL PLUGIN  statement for server plugins, the  INSTALL COMPONENT  statement for components offers the significant advantage that it is not necessary to know any platform-specific file name suffix for naming the component. This means that a given  INSTALL COMPONENT  statement can be executed uniformly across platforms. • UNINSTALL COMPONENT  deactivates components and unloads them from the server. The loader service also unregisters the components from the  mysql.component  system table so that the server no longer loads them during its startup sequence for subsequent restarts. • INSTALL COMPONENT  loads components into the server. The components become active immediately. The loader service also registers loaded components in the  mysql.component  system table. For subsequent server restarts, the loader service loads any components listed in  mysql.component during the startup sequence. This occurs even if the server is started with the  --skip-grant-tables option. •A component that implements a loadable function for accessing query attributes. See Section 9.6, “Query Attributes” . •A component that enables applications to add their own message events to the audit log. See Section 6.4.6, “The Audit Message Component” . •Keyring components provide secure storage for sensitive information. See Section 6.4.4, “The MySQL Keyring” . •A component for checking passwords. See Section 6.4.3, “The Password Validation Component” .