From: Alvar Freude <alvar@a-blast.org>
To: Eric <emayo@pozicom.net>
To: pgsql-sql@postgresql.org
Subject: Re: 2 Selects 1 is faster, why?
Date: Wed, 26 Jun 2002 17:34:47 +0200
Message-ID: <1371510000.1025105687@gnarzelwicht.delirium-arts.de> (raw)
In-Reply-To: <afag3c$kce$1@news.hub.org>
References: <afag3c$kce$1@news.hub.org>
Hi,
-- Eric <emayo@pozicom.net> wrote:
> If I perform the following 2 selects, the first one is EXTREMELY slow
> where the 2nd one is very fast.
[...]
> Why would 2 be so much faster? I have ran the EXPLAIN on this and index
> scans are being used.
I guess, the first query has to search for all ol.orderid the equivalent
o.orderid; the second variant only has to search for '1234' in each
?.orderid, which is much faster.
Explizit joins should speed up this!
> NOTE: The actual queries return more information than this, but the
> fundamental change shown above seems to give me the instant response I am
> looking for. (1) takes about 60 seconds to run and (2) takes 3-5 seconds
> to run.
3-5 seconds seems very long to me, if indexes are used and the result is
not a set of thousands of rows; are you sure?
Ciao
Alvar
--
// Unterschreiben! http://www.odem.org/informationsfreiheit/
// Internet am Telefon: http://www.teletrust.info/
// Das freieste Medium? http://www.odem.org/insert_coin/
// Blaster: http://www.assoziations-blaster.de/
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: alvar@a-blast.org, emayo@pozicom.net
Subject: Re: 2 Selects 1 is faster, why?
In-Reply-To: <1371510000.1025105687@gnarzelwicht.delirium-arts.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox