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Thread: reorgchk

  1. #1
    Join Date
    Nov 2003
    Posts
    68

    Unanswered: reorgchk

    hi !
    reorgchk update statistics on table all

    what is use of this .
    i t will improve the perpormanc or not ?
    daiil i have to do this ? or not?

    pl tell me to improve perpormance.

  2. #2
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    Reorgchk will tell you whether you need to reorg the tables\indexes. If needed, reorgs can definitely improve performance.

    After a reorg, you should update statistics with runstats. Statistics can also be updated during the reorgchk. Accurate statistics helps DB2 choose the right access path to retrieve the data.

  3. #3
    Join Date
    Jul 2003
    Location
    Austin, TX, USA
    Posts
    278

    Reorgchk

    Hi,

    Just to add to what Marcus said it is also advisable to do a runstats for all the tables at regular intervals as that helps db2 to choose the best optmized path while executing access plans.

    Secondly if you need to do a reorg as suggested by the reorgchk then please remember to commit afer you have reorged a few tables as reorg is a log intensive process and also takes time.

    regards

    nitin.

  4. #4
    Join Date
    Apr 2003
    Location
    P.R.China
    Posts
    6

    Smile remember use proper index

    add one thing: when there is more than one index for the table, you should use the most used one to reorganize your table (to gain best performance)

  5. #5
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    The index you use to reorg a table determines the clustering of the table. If the most used index is a single column unique index, then that is often not a good candidate for clustering, even if it is the most used index.

    Clustering has been discussed at length in other threads in this forum, with some examples and rules of thumb about choosing the clustering.

    Clustering can also be designated by defining one of the indexes as the clustering index, in which case no index need be specified during the table reorg. If a clustering index has been defined, and an index is specified for the table reorg, then it must be the same as the clustering index.

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