Re: database performance and query performance question

From: Hannu Krosing <hannu(at)tm(dot)ee>
To: "Shea,Dan [CIS]" <Dan(dot)Shea(at)ec(dot)gc(dot)ca>
Cc: "'josh(at)agliodbs(dot)com'" <josh(at)agliodbs(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: database performance and query performance question
Date: 2004-01-22 20:46:46
Message-ID: 1074804406.2592.2.camel@fuji.krosing.net
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Shea,Dan [CIS] kirjutas N, 22.01.2004 kell 22:35:
> Something that I do not understand is why if you use a valid_time =
> '2004-01-22 00:00:00' the query will use the index but if you do a
> valid_time > '2004-01-22 00:00:00' it does not use the index?

It probably can't tell if > is selective enough to justify using index.

Together with "limit 10" it may be.

You could try

explain analyze select * from forecastelement where valid_time between
'2004-01-22'::date and '2004-01-22'::date limit 10;

to see if this is considered good enough.

--------------
Hannu

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