public inbox for [email protected]  

help / color / mirror / Atom feed

From: Neil Conway <[email protected]>
To: Guillaume Lelarge <[email protected]>
Cc: [email protected]
Cc: pgsql-hackers <[email protected]>
Cc: Tom Lane <[email protected]>
Subject: row-level stats and last analyze time
Date: Tue, 24 Apr 2007 17:38:59 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

[ 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

view thread (11+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: row-level stats and last analyze time
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox