Bitmap indexes and star transformation
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Thread: Bitmap indexes and star transformation

  1. #1
    Join Date
    Feb 2001
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    I was thinking on turning the STAR_TRANSFORMATION_ENABLED parameter to true in our new data warehouse to help us in any performance gains. I was wondering if we need Bitmap indexes to be created on our tables for the star_transformation to work. Please advice

    Db - 8.1.7
    server- unix

    Thanks
    Vj

  2. #2
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    Does the application design state it uses star schema?

  3. #3
    Join Date
    Feb 2001
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    Yes, the design states that it will use the star schema.

  4. #4
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    In init.ore file, Set the following parameters:

    Bitmap_Merge_Area_Size = 8388608
    Create_Bitmap_Area_Size = 8388608
    Star_Transformation_enabled = true
    Query_Rewrite_enabled = true
    Query_Rewrite_integrity = enforced or trusted


  5. #5
    Join Date
    Feb 2001
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    Thanks for the reply Tamilselvan,
    There are no Bitmap indexes in the database right now(all the indexes are B*tree). Do we need to have bitmap indexes for the star transformation to work?
    Thanks
    Vj

  6. #6
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    Even bitmap index is not available, STAR transformation will work with normal B-Tree indexes..

  7. #7
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    Feb 2001
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    Thankyou

  8. #8
    Join Date
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    Originally posted by Nugpot
    Thanks for the reply Tamilselvan,
    There are no Bitmap indexes in the database right now(all the indexes are B*tree). Do we need to have bitmap indexes for the star transformation to work?
    Thanks
    Vj
    ... and when/if you make those bitmap indexes collect histograms for the bitmap-indexed columns.

    Oracle Certified Master
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