From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Gregory Stark <gsstark@mit.edu>
Cc: Luke Lonergan <llonergan@greenplum.com>
Cc: Chad Wagner <chad.wagner@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>
Cc: Igor Lobanov <ilobanov@swsoft.com>
Cc: Richard Huxton <dev@archonet.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Querying distinct values from a large table
Date: Wed, 31 Jan 2007 00:55:19 -0500
Message-ID: <16278.1170222919@sss.pgh.pa.us> (raw)
In-Reply-To: <20070130170443.GJ2303@alvh.no-ip.org>
References: <C1E49CB9.199A4%llonergan@greenplum.com>
<87d54wmpvd.fsf@stark.xeocode.com>
<20070130170443.GJ2303@alvh.no-ip.org>
Alvaro Herrera <alvherre@commandprompt.com> writes:
> Gregory Stark wrote:
>> (Incidentally I'm not sure where 2-5x comes from. It's entirely dependant on
>> your data distribution. It's not hard to come up with distributions where it's
>> 1000x as fast and others where there's no speed difference.)
> So the figure is really "1-1000x"? I bet this one is more impressive in
> PHB terms.
Luke has a bad habit of quoting numbers that are obviously derived from
narrow benchmarking scenarios as Universal Truths, rather than providing
the context they were derived in. I wish he'd stop doing that...
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, alvherre@commandprompt.com, gsstark@mit.edu, llonergan@greenplum.com, chad.wagner@gmail.com, simon@2ndquadrant.com, ilobanov@swsoft.com, dev@archonet.com
Subject: Re: Querying distinct values from a large table
In-Reply-To: <16278.1170222919@sss.pgh.pa.us>
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