• http://www.SQLpassion.at Klaus Aschenbrenner

    Hello John,

    Nice work!
    But when I’m running your demo script on SQL2012 I still get a warning in the SELECT operator of the execution plan: “type conversation may affect cardinality estimate in query plan choice”.



    • http://www.johnsansom.com John Sansom

      Hi Klaus,

      Thanks, delighted that you enjoyed the post sir!

      Your observation is spot on chap. The example scripts were built/tested on SQL Server 2008 R2, as was the actual production issue that the post is about. As you have seen, in SQL 2012 a Warning is placed on the SELECT operator of the execution plan. Quite a helpful addition to the plan and I would suggest heeding the advice as appropriate, that is to say take it on board and evaluate how it would effect your given case.

      As an aside, based on our other discussions offline with Mr White I don’t think I’ll extend the post here just yet as I don’t want to detract from the main theme. However, should you chaps decide to write about it I’d be happy to include a reference to your posts for further reading.

      Good stuff!

  • http://sqlbyparts.com Martin Cairns

    So, how long does DBCC CheckDB now take on that database with the indexed calculated columns? RE: http://www.sqlskills.com/blogs/paul/dbcc-checkdb-performance-and-computed-column-indexes/

    • http://www.johnsansom.com John Sansom

      Ha! I was thinking the same thing myself earlier today when I saw Paul’s post. Thankfully the work-around did not stay in production long enough to have to find out….

  • http://www.chrisyatessql.wordpress.com Chris Yates

    Nice work around! I totally missed the tip of the hat you gave Brent; I would have overlooked that on my first run through. Is a good one to remember. Recently had a similar issue with one of ours that was index related along the same lines that included a third party vendor that we couldn’t wait for. It’s refreshing to see some real world posts on issues being faced everyday. Nicely done sir.

    • http://www.johnsansom.com John Sansom

      Cheers Chris!

      Every once in a while I try to share a from the trenches DBA post. Makes a nice change from all that Professional Development fluff ;-)