[From SQL Server Performance
How do you determine how well your application is performing? What tools can you use? Every developer needs to make sure that each application TSQL statement is optimized. By tuning each query you can make sure that your application is running as efficient as possible. It is much easier to make modifications to application code while you are working in a development environment. Once your code is in production making modifications to optimize your code might take a long time, or even be impossible. This is why you need to review your application code performance periodically during the application development process. This article will give you a few different ideas on how to identify slow running queries and provide you with some tips on monitor your query performance while you make iterative changes to each query to try and improve performance.
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