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Query Analyzer - Execution Time

  • December 29, 2004 at 5:46 pm

    #165613

    Some time ago I recall reading a post about how you could clear QA after executing a query. Basically if you run the same query twice, it runs the second time much faster than the first. I would appreciate being reminded of what to execute so that the query takes the same amount of time.

    Thanks you,

    DB

     

  • December 30, 2004 at 1:21 am

    #535372

    The second time it usually runs faster, because the execution plan is cached and reused. To start with the same condition do

    DBCC DROPCLEANBUFFERS

    DBCC FREEPROCCACHE

     

    You might NOT want to do this on a production server.

    --
    Frank Kalis
    Microsoft SQL Server MVP
    Webmaster: http://www.insidesql.org/blogs
    My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

  • December 30, 2004 at 9:23 am

    #535415

    Thank you Frank. Just what I was looking for!

    Happy New Year!

    Deborah

  • December 30, 2004 at 9:33 am

    #535418

    Actually... I have three queries that I am comparing. I have been running them with those two commands in between over an over. I get different times each time (for each select). Not radical - between 22 and 25 secs. Is there anything else I can execute so that I can get the same time each time? I am running on my own sql server - no one else is accessing my machine and I am not running anything else (that is doing anything at the moment anyway) on my machine.

    Thanks - DB

  • January 4, 2005 at 7:55 am

    #535781

    Be sure to run "CHECKPOINT" before dropping the cleanbuffers.  Otherwise it may not have the desired effect.

  • January 4, 2005 at 9:39 am

    #535800

    Thanks. That seems to help.

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