10 essential performance tips for MySQL

As with all relational databases, MySQL can prove to be a complicated beast, one that can crawl to a halt at a moment's notice, leaving your applications in the lurch and your business on the line.
The truth is, common mistakes underlie most MySQL performance problems. To ensure your MySQL server hums along at top speed, providing stable and consistent performance, it is important to eliminate these mistakes, which are often obscured by some subtlety in your workload or a configuration trap.

http://www.infoworld.com/d/data-management/10-essential-performance-tips-mysql-192815