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Cost Threshold for Parallelism

  • July 14, 2014 at 4:44 am

    #309072

    Hi

    I have a query that use parallelism and takes 6 secs to run. I wanted to see how this would perform without parallelism and so set the threshold to 10, however my query still uses parallelism. Have I missed another setting somewhere?

    Thanks

  • July 14, 2014 at 4:57 am

    #1729095

    Cost != duration.

    Check the execution plan for the query, see what the cost is, set cost threshold above that. Or just use the maxdop hint on that query.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • July 14, 2014 at 5:10 am

    #1729102

    Ah yes thats sorted it, I was reading this article where it says "Estimatedcost in seconds.." which is what confused me.

    http://msdn.microsoft.com/en-us/library/ms190949.aspx

    Hopefully catch your session at SQLBits later this week.

    Thanks

  • July 14, 2014 at 5:24 am

    #1729105

    That estimated cost isn't in real "seconds." It's just a number used for the internal calculations.

    "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

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