Frequent updates to grant tables, including servers table and plugin, via appropriate statements (e.g. GRANT/REVOKE, CREATE/DROP USER, CREATE/DROP SERVER, INSTALL/UNINSTALL plugin) may increase memory usage. As not-freed memory chunks are relatively small, one would experience noticable memory increase only if there were thousands or millions updates to grant tables. This happens because when removing a record (REVOKE/DROP/UNINSTALL) from cache, we do not release memory back to an operating system. This memory is freed on FLUSH PRIVILEGES or server restart. To avoid memory usage increase, we should release memory immediately.