Approved

Please see the attached file.
>From pgsql-bugs-owner(at)postgresql(dot)org Sat Jun 7 05:36:36 2003
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Date: Fri, 06 Jun 2003 19:30:32 -0400
From: Dmitry Tkach <dmitry(at)openratings(dot)com>
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To: pgsql-bugs(at)postgresql(dot)org
Subject: Compund indexes and ORs
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Here is a trouble I am having, that looks like a bug to me:

create table abc (a int, b int, c int);
create index abc_idx on abc (a,b,c);
set enable_seqscan=off;

explain select * from abc where a in (1,2,3);

QUERY
PLAN
------------------------------------------------------------------------
-------
Index Scan using abc_idx, abc_idx on abc (cost=0.00..34.16 rows=10
width=12)
Index Cond: ((a = 1) OR (a = 2))
(2 rows)

Looks great - just what I expect, *but*:

explain select * from abc where a=1 and b in (1,2);

QUERY PLAN
---------------------------------------------------------------------
Index Scan using abc_idx on abc (cost=0.00..17.09 rows=1 width=12)
Index Cond: (a = 1)
Filter: ((b = 1) OR (b = 2))

Now, why doesn't it want to use the index for the second condition???
Any ideas?

Thanks a lot!

Dima