Re: Status of 8.3 patches

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
Cc: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Neil Conway <neilc(at)samurai(dot)com>, ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>
Subject: Re: Status of 8.3 patches
Date: 2007-08-20 20:44:22
Message-ID: 20070820204422.GW27916@alvh.no-ip.org
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Joshua D. Drake wrote:
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> Heikki Linnakangas wrote:
> > Joshua D. Drake wrote:
> >> Heikki Linnakangas wrote:
> >>> Bruce Momjian wrote:
> >>>> o Automatic adjustment of bgwriter_lru_maxpages
> >>>>
> >>>> We show this as waiting for performance results. I am thinking we
> >>>> should hold this for 8.4.
> >>> Agreed. I spent close to a week trying different benchmarks and
> >>> configurations and simple test cases on a test server and my laptop, and
> >>> couldn't demonstrate bgwriter making a positive impact in any
> >>> configuration I tried. The theory behind the patch is sound, but it
> >>> looks like a lot more testing and analysis is needed.
> >> Wouldn't real world testing be needed to actually gain insight to this
> >> patch?
> >
> > I would expect a fairly static benchmark workload to benefit from having
> > a bgwriter, more so than more unpredictable real world applications.
>
> Hmmm, I find that real world applications are quite predictable over
> time. Certainly you have spikes (good pr, whatever) but in general with
> a little bit of monitoring it is quite possible to evaluate a generally
> expected result.
>
> I guess my point is, if the patch looks good and does not appear to hurt
> anything, why not apply it? At least that way we can start to review the
> progress of the feature itself as it starts to see use.

Yeah, you mean like commit_delay. It really worked great, that
reviewing of a feature, you know. It only took 3 years until someone
realized that it didn't work as advertised.

--
Alvaro Herrera http://www.amazon.com/gp/registry/5ZYLFMCVHXC
"En las profundidades de nuestro inconsciente hay una obsesiva necesidad
de un universo lógico y coherente. Pero el universo real se halla siempre
un paso más allá de la lógica" (Irulan)

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