Re: Increase default effective_cache_size?

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org, Russ Brown <pickscrape(at)gmail(dot)com>
Subject: Re: Increase default effective_cache_size?
Date: 2006-09-24 00:14:45
Message-ID: 4515CDF5.9030808@commandprompt.com
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>> 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.

Joshua D. Drake
>
> regards, tom lane
>
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