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: | 1999-04-18 09:25:47 |
Message-ID: | Pine.SOL2.3.96.SK.990418132247.7864A-100000@sun.med.ru |
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Thread: | |
Lists: | pgsql-general |
Hi!
On Fri, 16 Apr 1999, Jackson, DeJuan wrote:
> try:
> EXPLAIN SELECT pos_id, rating
> FROM pos_rating pr
> WHERE date_i = current_date AND city_id = 2 AND
> EXISTS (SELECT DISTINCT pos_id FROM positions p WHERE subsec_id = 1 AND
> status = 'A' AND pr.pos_id=p.pos_id)
> ORDER BY rating;
This probably will help, thanks.
> Index date_i and city_id only.
Why? How do I find (for any given query) what indices I do need?
Postgres (being just a program) definetely have a set of rules where to use
and where not to use indicies. Any way for us to know/understand these
rules? Any general rules?
> -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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