From: Neil Conway <neilc@samurai.com>
To: Guillaume Lelarge <guillaume@lelarge.info>
Cc: pgsql-docs@postgresql.org, pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Subject: row-level stats and last analyze time
Date: Tue, 24 Apr 2007 17:38:59 -0400
Message-ID: <1177450739.16415.249.camel@localhost.localdomain> (raw)
In-Reply-To: <462B6CEB.4010109@lelarge.info>
References: <462B6CEB.4010109@lelarge.info>
[ CC'ing -hackers ]
On Sun, 2007-04-22 at 16:10 +0200, Guillaume Lelarge wrote:
> This patch adds a sentence on monitoring.sgml explaining that
> stats_row_level needs to be enabled if user wants to get last
> vacuum/analyze execution time.
This behavior was introduced in r1.120 of postmaster/pgstat.c:
Modify pgstats code to reduce performance penalties from
oversized stats data files: avoid creating stats
hashtable entries for tables that aren't being touched
except by vacuum/analyze [...]
which included other modifications to reduce the pgstat I/O volume in
8.1. I don't think this particular change was wise: the reduction in
pgstat volume is pretty marginal, and it is counter-intuitive for
stats_row_level to effect whether the last ANALYZE / VACUUM is recorded.
(Plus, the optimization is not even enabled with the default
postgresql.conf settings.)
-Neil
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To: pgsql-hackers@postgresql.org
Cc: neilc@samurai.com, guillaume@lelarge.info, tgl@sss.pgh.pa.us
Subject: Re: row-level stats and last analyze time
In-Reply-To: <1177450739.16415.249.camel@localhost.localdomain>
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