He used the InnoDB storage engine in MySQL instead of the default MyISAM. InnoDB is a lot more fault-tolerant than MyISAM but it is a lot slower, especially in

He used the InnoDB storage engine in MySQL instead of the default MyISAM. InnoDB is a lot more fault-tolerant than MyISAM but it is a lot slower, especially in COUNT operations. That's one of the more interesting attributes of MySQL: pluggable storage engines let you choose the characteristics most suitable for your architecture. I've heard people criticising MyISAM as less reliable but I've been using it in production for at least five years with no data loss. It is in an architecture, though, where data is replicated to several servers so we don't care so much about reliability on any one box. The MyISAM full-text search and speed are very nice. Nonetheless, he did present a very interesting case for DB2.