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Thread: re: puzzling performance of query

  1. #1
    Join Date
    Jan 2004
    Posts
    58

    Question re: puzzling performance of query

    hi! ,

    I have a query that is taking 14-15 seconds to complete in prod onsite..

    Its taking for ever to run about 45 minutes in a similar environment
    simulated at our site ..

    When I look at the explain plans they look exactly the same
    except for the order of the indexes ...!!!

    Could that be the problem for the poor performance at our site ?

    Any ideas , hints , help would be appreciated ...!!!

    i did the following on our site
    execute dbms_stats.gather_schema_stats('schema_name) ..

    thanks,
    harish
    thanks,
    harish

  2. #2
    Join Date
    Sep 2002
    Location
    England
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    7,334
    no version, no explain plans, no table structures, no data sizes = no help

  3. #3
    Join Date
    Nov 2000
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    Pittsburgh, PA
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    Originally posted by davey23uk
    no version, no explain plans, no table structures, no data sizes = no help
    Agreed. But if you know the order of the indexs is different, then change the order at the site running slower. Because, sometimes the order matters.

  4. #4
    Join Date
    May 2000
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    ATLANTA, GA, USA
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    ========
    Its taking for ever to run about 45 minutes in a similar environment
    simulated at our site ..
    =========

    No 2 environments are same. You can find 100s of differences if you dig into deep.

    Tamil

  5. #5
    Join Date
    Sep 2002
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    England
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    similar != same

    he didnt say they were the same

  6. #6
    Join Date
    Sep 2000
    Location
    Chicago, IL
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    316
    what version are you on ?

    Have you looked to confirm that the stats were generated when you ran a "dbms_stats.gather_schema_stats('schema_name" ??


    The reason I ask is because I ran the gather schema stats (on our 9204 database), and it did not gather any stats (I did not spend too much time investigating) ... I just ran gather table stats (since there were only 5 table).

    Make sure the stats are gathered at the same level (tables, indexes, etc) on both the instances.

    Good luck.

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