Database Performance Testing
Knowing how to identify performance issues and knowing how to fix them are great skills to have. The problem, though, is that you need to be able to demonstrate that the improvements you make are real improvements. While you can, and should, capture the performance metrics before and after you tune a query or add an index, the best way to be sure you’re looking at measurable improvement is to put the changes you make to work. Testing means more than simply running a query a few times and then putting it into your production system with your fingers crossed. You need to have a systematic way to validate performance improvements using the full panoply of queries that are run against your system in a realistic manner. Introduced with the 2012 version, SQL Server provides such a mechanism through its Distributed Replay tool.