I listened to episode 35 of FLOSS Weekly that interviewed Brian Aker, creator of the Drizzle fork from MySQL. As most recent episodes of FLOSS Weekly, it is pretty good technical material. What I found interesting was the technical vision behind Drizzle, and how they are aggressively going for quite wide multicore hosts.
Drizzle is really aiming at what they see as the long-term future: 64 cores or more. MySQL now being owned by Sun, it sounds like they caught the Niagara bug… but of course they are also looking at x86 hosts. They are doing this in part by tackling a type of problem that is mostly read access, not intense on write activity. Drizzle also removes some heavy-duty DB features like stored procedures to focus on applications that make plain simple SQL queries. Only loads of them. Examples are typical web properties like Yahoo, Google, and eBay.
What was also interesting was the general attitude to be modern in the code. All old 16-bit (x86 yuck) code is gone, as well as 32-bit support (any serious DB server is 64-bit machine anyway). Also, C99 is used throughout. Quite a refreshing take on something that did start with a decade-old code.
The project is hosted at https://launchpad.net/drizzle, where there is more information, code, etc. I have not really checked that part out.
But if you have time, do listen to the podcast. FLOSS weekly is one of my regular listens.