Re: Increase default effective_cache_size?

From: Gevik Babakhani <pgdev(at)xs4all(dot)nl>
To: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org, Russ Brown <pickscrape(at)gmail(dot)com>
Subject: Re: Increase default effective_cache_size?
Date: 2006-09-24 00:37:29
Message-ID: 1159058249.5087.10.camel@voyager.truesoftware.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general pgsql-hackers

On Sat, 2006-09-23 at 17:14 -0700, Joshua D. Drake wrote:
> >> Thank you: the problem was the effective_cache_size (which I hadn't
> >> changed from the default of 1000). This machine doesn't have loads of
> >> RAM, but I knocked it up to 65536 and now the query uses the index,
> >> without having to change the statistics.
> >
> > Considering recent discussion about how 8.2 is probably noticeably more
> > sensitive to effective_cache_size than prior releases, I wonder whether
> > it's not time to adopt a larger default value for that setting. The
> > current default of 1000 pages (8Mb) seems really pretty silly for modern
> > machines; we could certainly set it to 10 times that without problems,
> > and maybe much more. Thoughts?
>
> I think that 128 megs is probably a reasonable starting point. I know
> plenty of people that run postgresql on 512 megs of ram. If you take
> into account shared buffers and work mem, that seems like a reasonable
> starting point.
>

I agree, Adopting a higher effective_cache_size seems to be a good thing
to do.

(hmmm.... I must be dreaming again.... But I cannot stop wondering how
it would be to have a smart "agent" that configures these values by
analyzing the machine power and statistical values gathered from
database usage......)

In response to

Browse pgsql-general by date

  From Date Subject
Next Message Stephen Frost 2006-09-24 00:59:58 Re: Increase default effective_cache_size?
Previous Message Joshua D. Drake 2006-09-24 00:14:45 Re: Increase default effective_cache_size?

Browse pgsql-hackers by date

  From Date Subject
Next Message Stephen Frost 2006-09-24 00:59:58 Re: Increase default effective_cache_size?
Previous Message Mark Kirkwood 2006-09-24 00:16:30 Re: ReadBuffer(P_NEW) versus valid buffers