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Defragmentation in Sql Server 2005?

  • October 21, 2010 at 7:04 am

    #242014

    Hi

    What is Defragmentation ?

    Subha

  • October 21, 2010 at 7:11 am

    #1240283

    The process of removing fragmentation from an index so that, in theory, scans of the index perform better.

    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

  • October 21, 2010 at 7:27 am

    #1240297

    thank u, Gail......

  • October 21, 2010 at 11:14 am

    #1240475

    Hi Gail,

    What is the use of defragmenation ?

    In which situvation we have to go defragmentation.

    can you please explaine bit clearly..

    tx

    subu

  • October 21, 2010 at 11:24 am

    #1240481

    Indexes are built using extents (allocations of pages ) in the db file. As the index is built, it gets new pages from the file that are not necessarily contiguous, or near each other on disk.

    This means that to read an index, the head must move back and forth to find all the pages, and that slows performance. It can substantially slow performance in some cases.

    Rebuilding an index moves all the pages to a contiguous area by allocating new pages and building a new index. When that is done, the old index is removed.

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