Performance is frequently one of the last things on peoples’ minds when they’re developing a system.
Unfortunately, that means it usually becomes the biggest problem after that system goes to production. You can’t
simply rely on getting a phone call that tells you that procedure X on database Y that runs on server Z is running
slow. You have to have a mechanism in place to find this information for yourself. You also can’t work off the
general word slow. Slow compared to what? Last week? Last month? The way it ran in development? And once
you’ve identified something as running slow, you need to identify why. Does it need an index? Does it have an
index that it isn’t using? Is it the CPU, the disk, the memory, the number of users, the amount of data? And now
you’ve identified what and why, you have to do something about it. How? Rewrite the query? Change the WHERE
clause? The questions that will come your way when you start performance tuning are endless.
This book provides you with the tools you need to answer those questions. I’ll show you how to set up
mechanisms for collecting performance metrics on your server for the SQL Server instances and databases living
there. I’ll go over the more tactical methods of collecting data on individual T-SQL calls. Along the way, I’ll be
discussing index structure, choice, and maintenance; how best to write your T-SQL code; how to test that code;
and a whole slew of other topics. One of my goals when writing this book was to deliver all these things using
examples that resemble the types of queries you’ll see in the real world. The tools and methods presented are
mostly available with SQL Server Standard Edition, although some are available only with SQL Server Enterprise
Edition. These are called out whenever you might encounter them. Almost all the tuning advice in the book is
directly applicable to SQL Azure, as well as to the more earthbound SQL Server 2012.
The main point is to learn how to answer all those questions that are going to be presented to you. This book
gives you the tools to do that and to answer those questions in a methodical manner that eliminates much of the
guesswork that is so common in performance optimization today. Performance problems aren’t something to be
feared. With the right tools, you can tackle performance problems with a calmness and reliability that will earn
the respect of your peers and your clients and that will contribute directly to their success.
