Home Forums SQL Server 2008 T-SQL (SS2K8) NOT IN query very expensive, 100% CPU RE: NOT IN query very expensive, 100% CPU

  • September 13, 2012 at 10:50 am

    #1537344

    GilaMonster (9/13/2012)

    scogeb (9/13/2012)

    Jeff Moden (9/12/2012)

    Have you tried the NOT IN without the DISTINCT?

    Also, what's with all the LTRIM/RTRIM stuff? Data should be properly stored without leading spaces and trailing spaces hardly ever matter except when determining the actual number of bytes a strinng may contain.

    Yep, same deal with NOT IN without the DISTINCT, 100% CPU for way too long.

    Yeah, it will be. SQL ignores DISTINCT when specified in an IN/NOT IN subquery.

    Thanks, Gail. I learned something new today.

    Just to verify, I tried it a couple of different ways. On larger tables, it'll sometimes add a "Sort (Distinct Sort)" to the execution plan if the optimizer thinks it will help but I couldn't get it to add such a sort using DISTINCT on smaller tables.

    --Jeff Moden

    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.

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