A server-side plugin named Rewriter examines statements and may rewrite them, based on its in-memory cache of rewrite rules.

These statements are subject to rewriting:

Standalone statements and prepared statements are subject to rewriting. Statements occurring within view definitions or stored programs are not subject to rewriting.

The Rewriter plugin uses a database named query_rewrite containing a table named rewrite_rules. The table provides persistent storage for the rules that the plugin uses to decide whether to rewrite statements. Users communicate with the plugin by modifying the set of rules stored in this table. The plugin communicates with users by setting the message column of table rows.

The query_rewrite database contains a stored procedure named flush_rewrite_rules() that loads the contents of the rules table into the plugin.

A user-defined function named load_rewrite_rules() is used by the flush_rewrite_rules() stored procedure.

The Rewriter plugin exposes system variables that enable plugin configuration and status variables that provide runtime operational information.