The MySQL and Drizzle UDFs have been updated with support for "check and set" (a.k.a. CAS) operations, allowing stored procedures to call memcached operations in a way that enables lock-free algorithms in distributed systems. This feature is particularly useful when multiple systems need to update an item in a cache, making it easier to implement secure and efficient data synchronization. The UDFs are part of Patrick Galbraith's contributions to the memcached ecosystem, which also include support for user-defined functions for other databases such as MySQL, Drizzle, PostgreSQL, and Apache Derby.