SQLskills procs to analyze data skew and create filtered statistics

At PASS Summit 2013 I delivered a presentation titled: Skewed Data, Poor Cardinality Estimates, and Plans Gone Bad (you can watch this session on PASStv here). Note: please fast forward 4 mins as they didn’t tell me they were recording / publishing my “chatting” before the session – which is weird IMO but if you […]

The Accidental DBA (Day 15 of 30): Statistics Maintenance

This month the SQLskills team is presenting a series of blog posts aimed at helping Accidental/Junior DBAs ‘keep the SQL Server lights on’. It’s a little taster to let you know what we cover in our Immersion Event for The Accidental/Junior DBA, which we present several times each year. If you know someone who would benefit from […]

What caused that plan to go horribly wrong – should you update statistics?

I’ve been seeing this over the past few years, imagine this scenario: You have a stored procedure that runs well most of the time but sometimes it’s WAYYYYY off. It’s almost as though the performance of it went from great to horrible in a split second (like falling off of a cliff). You don’t know […]

Filtered indexes and filtered stats might become seriously out-of-date

Time flies when you're having fun, eh? This week Paul and I are in Dublin, Ireland delivering a deep technical "SQL Immersion Event" on Internals, Performance Tuning and Maintenance with our partner ProData (and having a blast – we have a really fun and very interactive group). And, today's an even more interesting day to be in […]

Database Maintenance Best Practices Part I – clarifying ambiguous recommendations for Sharepoint

OK, it seems as though there's A LOT of confusion about what steps are required for proper database maintenance. And, it seems as though some recommendations are being given as "quick fixes" without any real recommendation for root cause analysis. I'm not saying that the generalizations are horribly wrong but in many cases they're just […]

Auto update statistics and auto create statistics – should you leave them on and/or turn them on??

YES!!! OK, well, I guess I should be more specific because as in most things in SQL Server, the real answer is “it depends”. And for these two options, it depends mostly on your SQL Server version. Since SQL Server 7.0, the way that auto update works, has changed (much so for the better!!). So, […]

Statistics, query plans, and are you reading Conor’s blog?

I know that Paul and I recommended that you subscribe to Conor's blog… but have you? He's posted some great details on Partitioning (Part 1 and Part 2) as well as statistics and it always reminds me of how much I can learn from other people's perspectives! And, just to dove-tail on some of his statistics […]