From: Alvaro Herrera <alvherre@commandprompt.com>
To: Michael Fuhr <mike@fuhr.org>
Cc: Carlos Benkendorf <carlosbenkendorf@yahoo.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: How much expensive are row level statistics?
Date: Mon, 12 Dec 2005 10:23:42 -0300
Message-ID: <20051212132342.GE19555@surnet.cl> (raw)
In-Reply-To: <20051211194442.GA97174@winnie.fuhr.org>
References: <20051211115336.91041.qmail@web35506.mail.mud.yahoo.com>
<20051211194442.GA97174@winnie.fuhr.org>
Michael Fuhr wrote:
> On Sun, Dec 11, 2005 at 11:53:36AM +0000, Carlos Benkendorf wrote:
> > I would like to use autovacuum but is not too much expensive
> > collecting row level statistics?
>
> The cost depends on your usage patterns. I did tests with one of
> my applications and saw no significant performance difference for
> simple selects, but a series of insert/update/delete operations ran
> about 30% slower when block- and row-level statistics were enabled
> versus when the statistics collector was disabled.
This series of i/u/d operations ran with no sleep in between, right?
I wouldn't expect a normal OLTP operation to be like this. (If it is
you have a serious shortage of hardware ...)
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
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To: pgsql-performance@postgresql.org
Cc: alvherre@commandprompt.com, mike@fuhr.org, carlosbenkendorf@yahoo.com.br
Subject: Re: How much expensive are row level statistics?
In-Reply-To: <20051212132342.GE19555@surnet.cl>
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