IF Statement Branching and Parameter Sniffing
It can be tricky to remember that SQL Server doesn’t short circuit on IF statements in stored procedures. Even when you know this, sometimes it’s hard to recognize the impacts.
Index Rebuild, Reorganize, and Statistics in Maintenance Plans in SQL Server 2016
Working with maintenance plans is supposed to be easy, but I find it to be quite difficult.
New Free Webcasts on Interviewing and Indexing
Sharpen your performance tuning and indexing skills this summer, for free, one week at a time!
Using sp_WhoIsActive with Temp Tables to Limit Data Collected
The free sp_WhoIsActive procedure by Adam Machanic can be very useful for monitoring SQL Server: I’m a big fan.
But I’ve learned the hard way that it’s easy to collect too much information with sp_WhoIsActive, particularly if you set up jobs where you have the procedure log data to a table for later review. Collecting the text of SQL Server queries, their execution plans, and more, can take up a lot of room, and I’ve managed to fill up a server drive or two with a little over-eager collection. Whoops!
Join me for Why Did My Clever Index Change Backfire? at the 24 Hours of PASS
You’ve got a performance problem and you know just the cool index trick that will fix it! Until it goes utterly wrong. Join me for this free session in the 24 hours of PASS to see multiple quick demos of index changes that seem like a great idea… until they either don’t work, or make things worse. How to sign up My session is on Wed, July 19, 9 am Pacific / 12 pm Eastern / 4pm UTC.
How to Enable the Debug Channel in Extended Events for the Query Thread Profile XEvent in SQL Sever 2014+
Microsoft recently gave us a more lightweight way to trace data related to execution plan performance. As of SQL Server 2014 SP2, you can trace the query_thread_profile Extended Event.
How Much Longer Does it Take To Update Statistics with FULLSCAN?
When I was recently working on the course, “Should Developers Manage Index Maintenance?” I explained that in my experience, statistics maintenance can make more of a difference to performance than index maintenance can.
When does a Snapshot Transaction Really Begin?
They say, “never read the comments” on the internet, but I’m lucky to get lots of interesting points and questions in my comments.
When does physical reads include read-ahead reads in SQL Server?
SQL Server has more than one way to pull pages in from disk for your queries. SQL Server can do a physical read of an 8KB page, or an extent of 8 of those 8KB pages.
Top 5 Misleading SQL Server Performance Counters
Perfmon counters are an excellent tool for monitoring and sometimes troubleshooting Microsoft SQL Server. But some counters can get you into trouble, because they don’t mean what many people think. Learn what to look out for in the world of widely-used perfmon counters.