MovingOnUp - 3:15 pm on Sep 22, 2005 (gmt 0)
I have a relatively complex database model for one of my sites that started out fairly well normalized, but I ended up needing to build flattened summary tables due to performance issues. Many queries were joining 5-10 different tables, including several one-to-many relationships. I like to keep the time it takes to generate any one page on my site below 1/10th of a second, and some of the individual queries were taking several seconds. On top of that, the complexity was making it a bear to maintain.