Chapter 1: SQL Query Performance Tuning

Posted by Apress Free Book | SQL Server 2005/2008 January 26, 2010
Query performance tuning is an important part of today's database applications. Often you can achieve large savings in both time and money with proper query performance tuning


In this introductory chapter, you have seen that SQL Server performance tuning is an iterative process, consisting of identifying performance bottlenecks, troubleshooting their cause, applying different resolutions, quantifying performance improvements, and then going back to the start until your required performance level is reached.

To assist in this process, you should create a system baseline to compare with your modifications. Throughout the performance-tuning process, you need to be very objective about the amount of tuning you want to perform-you can always make a query run a little bit faster, but is the effort worth the cost? Finally, since performance depends on the pattern of user activity and data, you must reevaluate the database server performance on a regular basis.

To derive the optimal performance from a SQL Server database system, it is extremely important that you understand the stresses on the server created by the database application. In the next two chapters, I discuss how to analyze these stresses, both at a higher system level and at a lower SQL Server activities level. Then I show how to combine the two.

In the rest of the book, you will examine in depth the biggest SQL Server performance killers, as mentioned earlier in the chapter. You will learn how these individual factors can affect performance if used incorrectly and how to resolve or avoid these traps.

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