Re: Replacement for AND_EQUAL
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: "Oracle-L" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 12 Jan 2006 08:16:07 -0000
The least worst alternative is the INDEX_COMBINE,
which depends on _b_tree_bitmap_plans being set to
true (the default from 9i).
This allows the optimizer to consider acquiring rowids
from multiple B-trees, turning each rowid set into a
bitmap, then doing bitmap operations between sets
before converting back to rowids and visiting the table.
In principle it is much more powerful than AND_EQUAL
as it can use multi-column indexes, and doesn't require
an equality condition on the full index. (AND_EQUAL
required an equality condition on single-column (non-unique)
indexes)
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
Cost Based Oracle: Fundamentals
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Public Appearances - schedule updated 10th Jan 2006
----- Original Message -----
From: "Anand Rao" <panandrao@xxxxxxxxx>
To: "Oracle-L" <oracle-l@xxxxxxxxxxxxx>
Sent: Thursday, January 12, 2006 6:37 AM
Subject: Replacement for AND_EQUAL
Hi folks,
AND_EQUAL hint is deprecated in Oracle 10g.
does anyone know if there is another suitable replacement for it?
or
should i replace it with INDEX_JOIN or INDEX_COMBINE hints?
sure will test the queries with both these hints, but i have 100s of them to
replace before i go live with 10g.
thanks
anand
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