In order to understand which queries we should be focused on for query tuning, we need a method to accurately measure query performance. Also, as we make various attempts to improve query performance, we need to be able to capture the metrics that will enable us to understand how well our improvements are working or if they are working. Finally, we need to be able to measure the results of our improvements in order to both validate that they worked and also start the process over again, identifying the next poorly performing query.