Sometimes when reading what should be a very dry article you see an unintentional typo or some similar snafu that makes you spurt Dr. Pepper. Sometimes I wish my keyboard had the equivalent of a sneeze guard. From Tuning MySQL Server 4.0 Query Cache:
You may increase or degrease query_cache_size to find the value, which provides best performance for you.
So am I going to need one of these if I want my database to be tweaked to perfection? All joking aside, the query cache in the 4.0x series is, for practical web applications, one of the best improvements thus far. Though it annoyed me back in the 4.02 days when they changed the syntax for the configuration options. Why? No good reason. They’re on 4.09 now and things couldn’t be smoother though. I know of several major sites that run MySQL 4 as their main backend.