ICYMI: Query Optimization Phases, Observer Overhead, and Secrets of SP_Updatestats – SQL Server Performance

Do you do a bit of query tuning? Then check out this treasure trove of performance tuning advice!

Optimization Phases and Missed Opportunities and

Working Around Missed Optimizations

Paul White (b | t) writes two fascinating blog posts that go hand-in-hand concerning query optimization.  He goes into some deep details about how the query optimizer works, comparing various versions of SQL Server, and shows you several useful ways to assess query performance. Plus, there’s one handy trace flag too!

Observer Overhead and Wait Type Symptoms

Joe Sack (b | t) does a deep dive on “observer overhead”, that is, the overhead caused by whatever tool or method you use to monitor SQL Server performance and the impact which this overhead exerts on the wait statistics accumulated by SQL Server. Wait stats are my first-line defense in the war against poor performance, so this is a very important article for anyone learning or using wait stats.

Understanding What sp_updatestats Really Updates

If you assume that sp_updatestats does pretty much the same thing as the Update Statistics command, like I did, then you’d be wrong. Read this informative post from Erin Stellato (b | t), of SQLSkills.com, and also discover a useful script to help determine when a manual update of index statistics is needed.

I learned a lot from these articles. What about you?

-Kev

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