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How much free space in a page of SQL Server 2005?

  • March 2, 2010 at 12:07 pm

    #137453

    I got a number from a training class that a page has 8092 bytes free space.

    Then, I looked up MS web site it said a page has 8060 bytes (8KB).

    96 bytes of it is system header, so shouldn't the free space be 8060-96 = 7964bytes?

    And where 8092 free space comes from?

    I'm really confused, so any inputs would be greatly appreciated. Thanks.

  • March 2, 2010 at 1:03 pm

    #1127368

    The total size of a page is 8192 bytes. 8kB = 8*1024 bytes = 8192 bytes. So the number given in the course was slightly off.

    8060 is the max size of a row. Hence the maximum amount of data that can fit onto a page once the page header, row header and slot index are in place.

    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

  • March 2, 2010 at 1:20 pm

    #1127382

    Okay, I see. Thanks a lot for the explanation Gail.

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