Date: Wed, 9 Aug 2006 16:28:04 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: Christopher Browne <cbbrowne@acm.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: shared_buffer optimization
Message-ID: <20060809212804.GU40481@pervasive.com>
References: <44D86A00.90106@rentalia.com> <87u04nv2q6.fsf@wolfe.cbbrowne.com>
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On Tue, Aug 08, 2006 at 08:20:01AM -0400, Christopher Browne wrote:
> I'm not aware of any actual evidence having emerged that it is of any
> value to set shared buffers higher than 10000.

http://flightaware.com

They saw a large increase in how many concurrent connections they could
handle when they bumped shared_buffers up from ~10% to 50% of memory.
Back then they had 4G of memory. They're up to 12G right now, but
haven't bumped shared_buffers up.

Every single piece of advice I've seen on shared_buffers comes from the
7.x era, when our buffer management was extremely simplistic. IMO all of
that knowledge was made obsolete when 8.0 came out, and our handling of
shared_buffers has improved ever further since then. This is definately
an area that could use a lot more testing.
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461