Here's an excerpt from a database comparison between Oracle, DB2, MySQL,
SQLserver, and Sybase. (I just asked the author why postgres wasn't used.)
MySQL's great performance was due mostly to our use of an in-memory query
results cache that is new in MySQL 4.0.1. When we tested without this cache,
MySQL's performance fell by two-thirds.
Anyway, this confirms an earlier message suggesting that for web servers that
have relatively constant queries, query caching can be a Big Deal.
<http://www.eweek.com/article/0,3658,s=708&a=23115,00.asp>
