Date: Fri, 7 Oct 2005 12:48:16 +0200
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: count(*) using index scan in "query often,
	update rarely" environment
Message-ID: <20051007104816.GA8371@uio.no>
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On Fri, Oct 07, 2005 at 11:24:05AM +0200, Cestmir Hybl wrote:
> Isn't it possible (and reasonable) for these environments to keep track of
> whether there is a transaction in progress with update to given table and
> if not, use an index scan (count(*) where) or cached value (count(*)) to
> perform this kind of query?

Even if there is no running update, there might still be dead rows in the
table. In any case, of course, a new update could always be occurring while
your counting query was still running.

/* Steinar */
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Homepage: http://www.sesse.net/