Re: Quad processor options

From: Andrew McMillan <andrew(at)catalyst(dot)net(dot)nz>
To: Paul Tuckfield <paul(at)tuckfield(dot)com>
Cc: Bjoern Metzdorf <bm(at)turtle-entertainment(dot)de>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Quad processor options
Date: 2004-05-12 08:58:13
Message-ID: 1084352292.4785.37.camel@lamb.mcmillan.net.nz
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On Tue, 2004-05-11 at 15:46 -0700, Paul Tuckfield wrote:

> - the "cache" column shows that linux is using 2.3G for cache. (way too
> much) you generally want to give memory to postgres to keep it "close" to
> the user, not leave it unused to be claimed by linux cache (need to leave
> *some* for linux tho)
>
> My recommendations:
> - I'll bet you have a low value for shared buffers, like 10000. On
> your 3G system you should ramp up the value to at least 1G (125000 8k buffers)
> unless something else runs on the system. It's best to not do things too
> drastically, so if Im right and you sit at 10000 now, try going to
> 30000 then 60000 then 125000 or above.

Huh?

Doesn't this run counter to almost every piece of PostgreSQL performance
tuning advice given?

I run my own boxes with buffers set to around 10000-20000 and an
effective_cache_size = 375000 (8k pages - around 3G).

That's working well with PostgreSQL 7.4.2 under Debian "woody" (using
Oliver Elphick's backported packages from
http://people.debian.org/~elphick/debian/).

Regards,
Andrew.
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