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  1. #1
    Join Date
    Mar 2006
    Posts
    104

    Unanswered: Index usage on federated table access

    DB2 8.2.6 windows 2000 platform

    I have a view defined as a join of a federated table (nickname pointing a table in another database) and a local table. Both table have identical indexes.

    Question.

    Does DB2 use indexes on both the tables when a select is issued on the view?

    Thanks

  2. #2
    Join Date
    Jan 2003
    Posts
    1,605
    Hi,
    There is no garantee that DB2 will use index. You need to check it out with SQL access path.

    If index is created after nickname creation, you should recreate nickname, because at nickname creation all statistics on source table are collected and stored to local database catalog.

    Hope this helps,
    Grofaty

  3. #3
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650
    Given your scenario, I doubt indexes to be used .. Data will be shipped (likely from remote to local db) and then a join performed. Index on the remote table is a remote structure and therefore cannot be used to join with a local table.

    HTH

    Sathyaram
    Visit the new-look IDUG Website , register to gain access to the excellent content.

  4. #4
    Join Date
    Jun 2006
    Posts
    471

    federated

    the access plan should show where the join is performed, local or remote.
    there are some settings for federated db, that will push to the max, the data to the remote server and execute the join at remote server ..
    see info center and federated..
    Best Regards, Guy Przytula
    DB2 UDB LUW certified V6/7/8

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