MySQL 5.1 hasn’t gotten a lot of love, but it does introduce support for pluggable storage engines. And that’s required to use SphinxSE. Sphinx is a fast full text search engine. It doesn’t need to run as a MySQL storage engine to work, but doing that allows joining against other MySQL tables. So while I’m watching the future of MySQL alternatives, I’m also watching 5.1 bug fixes and playing with the CoolStack-packaged 5.1 on a friend’s box.