From: David Newall <postgresql@davidnewall.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Craig Ringer <craig@postnewspapers.com.au>
Cc: pgsql-performance@postgresql.org
Cc: robertmhaas@gmail.com
Cc: dcrooke@gmail.com
Subject: Re: pg_dump far too slow
Date: Mon, 22 Mar 2010 02:20:34 +1030
Message-ID: <4BA6404A.5040009@davidnewall.com> (raw)
In-Reply-To: <22117.1269185944@sss.pgh.pa.us>
References: <4B9C97E1.40509@davidnewall.com>
<24696.1268598111@sss.pgh.pa.us>
<4BA61C74.70506@davidnewall.com>
<4BA62596.8050604@postnewspapers.com.au>
<22117.1269185944@sss.pgh.pa.us>
Tom Lane wrote:
> I would bet that the reason for the slow throughput is that gzip
> is fruitlessly searching for compressible sequences. It won't find many.
>
Indeed, I didn't expect much reduction in size, but I also didn't expect
a four-order of magnitude increase in run-time (i.e. output at
10MB/second going down to 500KB/second), particularly as my estimate was
based on gzipping a previously gzipped file. I think it's probably
pathological data, as it were. Might even be of interest to gzip's
maintainers.
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To: pgsql-performance@postgresql.org
Cc: postgresql@davidnewall.com, tgl@sss.pgh.pa.us, craig@postnewspapers.com.au, robertmhaas@gmail.com, dcrooke@gmail.com
Subject: Re: pg_dump far too slow
In-Reply-To: <4BA6404A.5040009@davidnewall.com>
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