From: | Oleg Broytmann <phd(at)sun(dot)med(dot)ru> |
---|---|
To: | "Jackson, DeJuan" <djackson(at)cpsgroup(dot)com> |
Cc: | PostgreSQL <pgsql-general(at)postgreSQL(dot)org> |
Subject: | RE: [GENERAL] Optimal indicies |
Date: | 1999-04-21 08:54:19 |
Message-ID: | Pine.SOL2.3.96.SK.990421125028.22429A-100000@sun.med.ru |
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Lists: | pgsql-general |
Hi!
On Tue, 20 Apr 1999, Jackson, DeJuan wrote:
> The reason I chose those tow columns is because they are the only one that
> will be seen in that where clause.
> So position should be indexed on subsec_id, status, and pos_id.
Sounds reasonable.
> My general rule of thumb is to stay away from OR clause in PostgreSQL (which
> is what an IN or NOT IN translate to), and index the columns that are
I heared an advice (from Vadim, who implemented this) that IN is not
very effective. EXIST and correlated subqueries are much better.
> definitely included in most where clauses on that table.
Should these indicies be created as compound index (CREATE INDEX myindex
ON TABLE mytable (field1, field2)) or separated
(
CREATE INDEX myindex1 ON TABLE mytable (field1)
CREATE INDEX myindex2 ON TABLE mytable (field2)
)
?
> -DEJ
Oleg.
----
Oleg Broytmann http://members.xoom.com/phd2/ phd2(at)earthling(dot)net
Programmers don't die, they just GOSUB without RETURN.
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