index usage - total no of records - doubt
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Thread: index usage - total no of records - doubt

  1. #1
    Join Date
    Jul 2006
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    96

    index usage - total no of records - doubt

    hi, for Index can be used , if the table has how many records?
    i.e for few records is is not useful right?

  2. #2
    Join Date
    Aug 2002
    Location
    Colorado Springs
    Posts
    5,253
    Not neccessarily. If you have a single record in a tabvle with its highwater mark at 8Mb then an index is going to be faster at finding it.
    David Aldridge,
    "The Oracle Sponge"

    Senior Manager, Business Intelligence Development
    XM Satellite Radio
    Washington, DC

    Oracle ACE

  3. #3
    Join Date
    Nov 2004
    Location
    Mumbai, India
    Posts
    452
    A table rebuild is nessesary in this case. Isn't it dave?
    There are three kinds of lies: Lies, damned lies, and benchmarks...

    Unix is user friendly. It's just very particular about who it's friends are.

    Oracle DBA

  4. #4
    Join Date
    Dec 2006
    Location
    Brazil
    Posts
    36
    If you are using CBO (Cost Based Optimizer) there is no way to know if an index is going to be used or not. Oracle will get statistics on data dictionary and based on this cost will let index to be used or not.

    That's way Oracle is advising that RBO (Rule Based Optimizer) will be obsolete in further releases.

    Just keep your database with statistics updated and you may have a good access plan.
    Regards,

    Carlos Duarte
    Oracle Applications DBA

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