Re: Effective Cache Size

From: "Shridhar Daithankar" <shridhar_daithankar(at)persistent(dot)co(dot)in>
To: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Effective Cache Size
Date: 2003-09-17 11:03:09
Message-ID: 3F688CC5.12621.4EBFDCC@localhost
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On 17 Sep 2003 at 11:48, Nick Barr wrote:

> Hi,
>
> I have been following a thread on this list "Inconsistent performance"
> and had a few questions especially the bits about effective_cache_size.
> I have read some of the docs, and some other threads on this setting,
> and it seems to used by the planner to either choose a sequential or
> index scan. So it will not necessarily increase performance I suppose
> but instead choose the most optimal plan. Is this correct?

That is correct.

> Danger maths ahead. Beware!!!!
>
> <maths>
> 141816K buff
> + 1781764K cached
> -----------------
> 1923580K total
>
> effective_cache_size = 1923580 / 8 = 240447.5
> </maths>

That would be bit too aggressive. I would say set it around 200K to leave room
for odd stuff.

Rest seems fine with your configuration. Of course a latest version of
postgresql is always good though..

Bye
Shridhar

--
Power is danger. -- The Centurion, "Balance of Terror", stardate 1709.2

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