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Re: First steps with 8.3 and autovacuum launcher

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Guillaume Smet <guillaume(dot)smet(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, Gregory Stark <stark(at)enterprisedb(dot)com>, Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: First steps with 8.3 and autovacuum launcher
Date: 2007-10-04 13:04:06
Message-ID: 20071004130406.GE6176@alvh.no-ip.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Guillaume Smet escribió:
> Alvaro,
> 
> On 10/4/07, Alvaro Herrera <alvherre(at)commandprompt(dot)com> wrote:
> > I came up with the following patch.  What this does is cancel any
> > ANALYZE started by autovacuum, at the top of ALTER TABLE.
> 
> It doesn't seem to work for me. I still have my ALTER TABLEs waiting:
> \_ postgres: postgres cityvox [local] ALTER TABLE waiting
> \_ postgres: autovacuum worker process   cityvox
> \_ postgres: autovacuum worker process   cityvox
> \_ postgres: autovacuum worker process   cityvox
> 
> I have a lot of NOTICE:  cancelling auto-analyze lines in my log but
> it doesn't seem to change the overall behaviour (even if it's a bit
> better than before). With cost delay of 20:
> real    44m20.525s
> user    0m35.757s
> sys     0m2.985s
> compared to 51 minutes before applying your patch.

Hmm, it looks like the race condition Heikki mentioned is the culprit.
We need a way to stop future analyzes from starting.  Back to the
drawing board ...

-- 
Alvaro Herrera                               http://www.PlanetPostgreSQL.org/
Criptografía: Poderosa técnica algorítmica de codificación que es
empleada en la creación de manuales de computadores.

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Next:From: Andrew DunstanDate: 2007-10-04 13:22:02
Subject: Re: Not *quite* there on ecpg fixes
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Subject: Re: First steps with 8.3 and autovacuum launcher

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