polygonal labs » Bitwise gems - fast integer math
some example code for common bitwise operations
MySQL AB :: MySQL 5.0 Reference Manual :: 6.2.1 Optimizing Queries with EXPLAIN
Rails performance tip - using YSlow
MySQL :: A Quick Look at MySQL 5.4
info on some nice changes coming in MySQL 5.4, particuarly subquery optimisations
MySQL YourSQL | Cafuego
some handy tips on optimising MySQL settings
Reducing String duplication in Ruby