If you are developing for any database involved application that deals with a moderate quantity of data and you stick around long enough, you will find yourself investigating performance. Maybe you operate like our team did on a recent project where we started with some base expectations of performance, moved forward until gross disappointment set it, hacked at performance enhancements until we felt better about things, adjusted our expectations, and moved on. This cycle repeated itself many times and each time, I learned something new about how not to do a variety to things.
I won't spoil the fun for you, but if you are using SQL Server 2005 or greater, I will offer this one thing that I found enlightening: key-lookups in my query execution plans were my failure to understand(or care about) included columns. I would explain more myself, but that has already been done so very well in this post here by Joe Webb.
So this still counts as a blog entry right?
Cheers!
