I get the call, you get the call, everyone gets the call. “Hey, my app/procedure/query/report is running slow.” Now what do you do? You go to my full day session at SQL Rally, that’s what. Assuming you vote for it.
I didn’t post the abstract I submitted for the SQL Rally before because I thought that it would be redudant. However, since it’s not right off the voting page (unless they updated it since I voted), if you’re interested, here’s what I thought I would do for a day. If it sounds good to you, please go here and vote for it.
One of the most common problems encountered in SQL Server is the slow running query. Once a query is identified as performing poorly, DBAs and developers frequently don’t understand how to diagnose the problem and often struggle to fix the problem. This one day seminar focuses exclusively on these two topics. Attendees will learn how to identify the queries that are performing badly and learn how to fix them. We will start by learning how to gather performance metrics, both server and query metrics, using tools available directly from Microsoft such as performance monitor, DMVs and Profiler. From there we’ll move into learning how the optimizer works and how it uses statistics to determine which indexes and other database objects can assist the performance of a query. The session takes considerable time to show exactly how to generate and read execution plans, the one best mechanism for observing how the optimizer works. We’ll then look at other DMVs that can assist you when performance tuning queries. With all this knowledge gathered, we’ll move into looking at common performance problems, how they evidence themselves in the metrics and execution plans, and how to address them. Finally, we’ll explore advanced methods for solving some of the more difficult query performance problems introducing such concepts as query hints, plan guides and plan forcing. Through all of this, best practices and common techniques will be reviewed. Attendees will go home with a working knowledge of query performance tuning, a set of methods for identifying poorly performing queries, scripts to assist in these processes and the knowledge of how fix performance problems in their own systems.
Although I would prefer that you voted for me, it’s more important that you vote at all (same thing as in real life). Please go here and select the sessions that you want to see.
I don’t generally do lots of blog aggregation and cross post linking & stuff. It’s just not something I’m that into. However, this time is an exception. Gail Shaw, Gila Monster to those who hang on out SQL Server Central, has posted an excellent explanation of times when Estimated and Actual row counts vary for a reason. I’m one of those who emphasises that differences between estimated & actual is an indication of… something. It could be out of date or missing statistics or it could be caused by query language like multi-statement table valued functions, but it’s usually and indication of a problem. Except when it’s not. Read Gail’s explanation for more.
Since I just spent a bit more than half of my 24 Hours of PASS presentation on tuning queries talking about monitoring performance, you could probably tell that I think that the two are inextricably linked. I’m not alone. Tom LaRock has put a post on why it’s important to understand the extent of your problem prior to attempting to fix it. It’s absolutely spot-on and a must read.
Remember, if someone says performance on a system you manage is slow, you have to ask, as compared to what? You need to understand what “normal” performance is on your system in order to arrive at the ability to identify a particular process as performing in an abnormal manner. That’s not to say that you couldn’t tune a query in complete isolation to a baseline of performance. Of course you could. The question that Tom is answering is, are you tuning the right query for the right reasons?
Oh, and for those that are interested, some of the presentations made during 24 Hours of PASS are now available for download. The rest of the sessions will be available after the Summit. If you haven’t made plans to go, I’d get on over there now and register.
The new book is up on Amazon. I only worked on three chapters of Rob Walter’s new book and that was after begging to only work on two, so I can’t take much credit for the effort that went into this book. However, thanks to our editor Jonathan Gennick, I was privileged to work with Rob & Carmen, if pretty indirectly. I know I mentioned the book before when it was put up on the Apress web site, but this is Amazon. Once it’s up on Amazon, it’s real.