The memcache_engine allows memcache to work as a storage engine to MySQL. This means that you can SELECT/UPDATE/ INSERTE/DELETE from it as though it is a table in MySQL. This is very experimental.
Release Notes: The project now uses libmemcached. The previous library was causing too many issues, and the new library works quite well. XML row format added, so the engine will now store data in memcached as XML (so the data can be read by both MySQL from memcached and any language that can parse XML). An issue with overwriting keys has been fixed.
Release Notes: Support for discovery of tables was added. Row level locks were implemented. A major bug in duplicate keys was fixed, along with phantom rows for updates. The server status has been updated.
Release Notes: One memory leak was fixed. An information schema for memcached servers being used was added. This allows you to know the current state of servers you are using (objects held, bytes used, transferred data, etc.).
Release Notes: Support has been added for packed rows (uses less memory). Support has been fixed for IN() operations. A bug in UPDATE when ORDER BY was given has been fixed.
Release Notes: Table space support was added. The engine can now use multiple memcached servers.