Re: Indexes Used per Query

Apart from the special case of bitmap indexes which are almost invariable combined through AND and OR, it is possible for Oracle to use other access paths that combine multiple indexes.

The AND-EQUAL path still exists, but with CBO the statistics have to be pretty finely balanced for it to be used unhinted. The INDEX_JOIN path has just been introduced (disabled, though) to allow a hash-join between indexes that bypasses the table completely.

Jonathan Lewis

Seminars on getting the best out of Oracle Last few places available for Sept 10th/11th See http://www.jlcomp.demon.co.uk/seminar.html

-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 14 August 2001 16:02

|Will the optimizer (CBO) ever use more than one index
|in the access path for a table in a query? I have
|never seen this behavior and have always been curious.
|

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Author: Jonathan Lewis
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