From: Tobias Brox <tobias@nordicbet.com>
To: kjelle@bingon.no
Cc: pgsql-performance@postgresql.org
Subject: Re: Too slow querying a table of 15 million records
Date: Tue, 28 Jun 2005 14:03:33 +0800
Message-ID: <20050628060333.GH7652@tobias.exoweb.net> (raw)
In-Reply-To: <19310.193.213.27.25.1119378838.squirrel@webmail.s7.itpays.net>
References: <19310.193.213.27.25.1119378838.squirrel@webmail.s7.itpays.net>
[kjelle@bingon.no - Tue at 08:33:58PM +0200]
> I use FreeBSD 4.11 with PostGreSQL 7.3.8.
(...)
> database=> explain select date_trunc('hour', time),count(*) as total from
> test where p1=53 and time > now() - interval '24 hours' group by
> date_trunc order by date_trunc ;
I haven't looked through all your email yet, but this phenomena have been up
at the list a couple of times. Try replacing "now() - interval '24 hours'"
with a fixed time stamp, and see if it helps.
pg7 will plan the query without knowledge of what "now() - interval '24
hours'" will compute to. This should be fixed in pg8.
--
Tobias Brox, +86-13521622905
Nordicbet, IT dept
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To: pgsql-performance@postgresql.org
Cc: tobias@nordicbet.com, kjelle@bingon.no
Subject: Re: Too slow querying a table of 15 million records
In-Reply-To: <20050628060333.GH7652@tobias.exoweb.net>
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