When optimizing your database server, you need to tune the performance of individual queries. This is as important as—perhaps even more important than—tuning other aspects of your server installation, that affect performance, such as hardware and software configurations.
Even if your database server runs on the most powerful hardware available, its performance can be negatively affected by a handful of misbehaving queries. In fact, even one bad query, sometimes called a "runaway query," can cause serious performance issues for your database.
Conversely, the overall performance of your database can be greatly improved by tuning a set of most expensive or most often executed queries. In this article, I will look at some of the techniques you can employ to identify and tune the most expensive and worst performing queries on your server.
* Analyzing execution plans
* Optimizing queries
* Estimated Cost of Execution
* Analyzing an Execution Plan
* The Covering Index
* Indexed Views
* Identifying Which Queries to Tune
* Customer Order Query Exercise