Fragmentation does not reduce for some tables

  • I am defragmenting the database as a maintenance work. But i found that some of the databases avg_fragmentation_in_percent does not reduce.But in some article i have seen that fragmentation on small indexes is often not controllable and The pages of small indexes are stored on mixed extents.

    So what is the limit for page count for which i can neglect the value of avg_fragmentation_in_percent?

    In some databases having page count 100 has shown reduce in fragmentation but some db having page count 68 does not reduce fragmentation. So how can i decide for which condition i should consider checking fragmentation?

  • 68 pages is too small to worry about. The usual threshold that's mentioned is 1000 pages. Not a hard and fast number, just a guide

    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
  • Aside what Gail has said check the index id for the object. If its a heap then it will naturally contain some fragmentation.

    The page allocation marker is 8 pages, any allocations over that will use uniform extents. This is detailed on msdn, sorry but I don't have link at present.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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