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 <[EMAIL PROTECTED]>
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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