Execution plan

  • Hi All,

    I have 2 sql sevr 2005 instances with same build no,same edition.

    I restored the database from one insatnce to another instance. But when i execute the same query in the second instance , it poduces are different plan and my query performance is slow now on one instance.

    Just wanted to understand how sql server or on what factors/basis sql servr produces are different plans if my stats are same ?

    Thanks in Advance.

  • Oracle_91 (9/10/2012)


    Hi All,

    I have 2 sql sevr 2005 instances with same build no,same edition.

    I restored the database from one insatnce to another instance. But when i execute the same query in the second instance , it poduces are different plan and my query performance is slow now on one instance.

    Just wanted to understand how sql server or on what factors/basis sql servr produces are different plans if my stats are same ?

    Thanks in Advance.

    Are there any differences in how the instances are configured? Are the instances on the same server or different servers? If different servers, how are these servers configured?

  • Both are two different server with configuration. But on the second servers there are 2 instances.

    One more thing, the second is not at all running on the second box.

  • Did you rebuild statistics?

    I do believe that even though the servers may be configured the same/same hardware, when you restore a database the stats get "out of whack".

    I may be wrong, and if I am someone will most likely point it out here. :w00t:

    ______________________________________________________________________

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  • Jason Selburg (9/12/2012)


    Did you rebuild statistics?

    I do believe that even though the servers may be configured the same/same hardware, when you restore a database the stats get "out of whack".

    I may be wrong, and if I am someone will most likely point it out here. :w00t:

    A restore will not affect the statistics. A restore gives us an exact page-for-page database as existed when the database was backed up.

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • Oracle_91 (9/10/2012)


    Hi All,

    I have 2 sql sevr 2005 instances with same build no,same edition.

    I restored the database from one insatnce to another instance. But when i execute the same query in the second instance , it poduces are different plan and my query performance is slow now on one instance.

    Just wanted to understand how sql server or on what factors/basis sql servr produces are different plans if my stats are same ?

    Thanks in Advance.

    If the optimizer chooses a parallel plan that could account for a difference. Can you please post both execution plans attached to this thread as .sqlplan files?

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • there could be some hardware allocation differnce like memory or cpu OR sme diiferent setting like maxdop etc

    -------Bhuvnesh----------
    I work only to learn Sql Server...though my company pays me for getting their stuff done;-)

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