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Sql Version Comparison

  • February 11, 2013 at 3:55 am

    #270611

    Hi,

    Could someone please confirm if the query optimiser differs between the following versions of SQL Server, and if possible what the differences are:

    - 2008 R2 RTM

    - 2008 R2 Sp1

    Thanks

  • February 11, 2013 at 4:05 am

    #1586453

    Only where the fixes listed for that Service Pack need it to. The general aim of a Service Pack is to fix bugs, but not to otherwise alter functionality, so you'd expect them to be very minor changes.

    The full list of fixes is here:

    http://support.microsoft.com/kb/2463333

    If you're seeing different plans/performance between the two versions, it's far more likely to be due to differences in statistics, data or parameter sniffing.

  • February 11, 2013 at 4:13 am

    #1586454

    Ok, thanks for your help.

  • February 11, 2013 at 5:00 am

    #1586463

    You should be aware that most changes to the optimizer, especially the ones that lead to plan instability, are not actually turned on when you install a service pack. Read here about trace flag 4199 which is how you enable them. Remember, thorough testing is your best friend in these situations.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • February 11, 2013 at 9:06 am

    #1586632

    Hi Grant,

    Thanks for your reply. Doesnt this trace only apply to hotfixes? I was under the impression that Service Packs enable this by default. I believe this is also what the article says (alhtough I may have misinterpreted it).

    Thanks

  • February 11, 2013 at 9:09 am

    #1586633

    Not sure. Reading the KB, it could be interpreted to only apply to CU & hot fixes, but I don't have a definitive answer there.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • February 11, 2013 at 9:39 am

    #1586649

    No problem. Thanks for your help with this.

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