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Bookmark lookup

  • March 10, 2008 at 7:27 am

    #120693

    I have created index (clustered and non clustered) for each most used columns on a table. I don't see any non indexed column in the query, but still I see bookmark look up in the execution plan. I am trying to avoid bookmark look up . Can anybody please suggest how I can avoid bookmark look up.

    Thanks in advance

  • March 10, 2008 at 7:34 am

    #787354

    Can you submit the query and table structure (with indeces)?

    Also note that the execution plans may vary based on the load. If your indexes are statistics are up to date, SQL Server will pick the most efficient ways almost all the time.

    Cheers,
    Prithiviraj Kulasingham

    http://preethiviraj.blogspot.com/

  • March 10, 2008 at 7:35 am

    #787357

    Additionally, if your query is not supported by a single non clustered index, there is a high possibility of book mark lookup.

    Cheers,
    Prithiviraj Kulasingham

    http://preethiviraj.blogspot.com/

  • March 10, 2008 at 8:39 am

    #787400

    You want to avoid bookmark lookups if you can, but you cannot avoid them. They are a part of every system, since you can't index for everything, and you don't want to.

    You want to avoid them in your most costly (in single cost or aggregate because they are run often) queries and shift them to less used queries.

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