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Thread: Bitmap index

  1. #1
    Join Date
    Dec 2001
    Posts
    80

    Unanswered: Bitmap index

    Oracle 8.1.7 is used, and the optimizer is using rule-based instead of cost-based, can bitmap index be used?

    select t2.client_id, t1.APPROVE_USER, to_char(t1.APPROVE_TIME, 'YYYYMMDDHHMMSS') APPROVE_TIME
    from cacc_amendment_history t1,
    (select a.client_id, max(b.amendment_id) as amendment_id
    from clients_amendment a, cacc_amendment_history b
    where a.amendment_id = b.amendment_id
    and b.APPROVE_STATUS = 'APP'
    group by a.client_id) t2
    where t1.amendment_id = t2.amendment_id
    order by t2.client_id;

    I do explain and found that table scan is used on table cacc_amendment_history, if I create a index on cacc_amendment_history(approve_status), index scan is used. However, if I create a bitmap index on cacc_amendment_history(approve_status), table scan is used.

  2. #2
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    Provided Answers: 1
    No, the RBO will never use a bitmap index:

    Perfornance Tuning Guide

  3. #3
    Join Date
    Dec 2001
    Posts
    80
    Andrew,
    Thx.

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