From: Jim C. Nasby <jim@nasby.net>
To: Brian Wipf <brian@clickspace.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: pgsql-performance@postgresql.org, Guido Neitzer <lists@event-s.net>
Subject: Re: shared_buffers > 284263 on OS X
Date: Mon, 27 Nov 2006 03:22:56 -0600
Message-ID: <20061127092256.GE67378@nasby.net> (raw)
In-Reply-To: <6ADBFE12-7A0D-4809-87CD-1F68755A8AD5@clickspace.com>
References: <B242A585-E94C-4ECA-8FA9-DCE72E1D8838@shoptoit.ca>
<82E59D2F-0946-4405-8F11-4CF5184A9399@fastcrypt.com>
<412.1163874633@sss.pgh.pa.us>
<817D9C4C-05F0-45FB-9D63-B63CFE2C009E@clickspace.com>
<20061126232523.GD39519@nasby.net>
<6ADBFE12-7A0D-4809-87CD-1F68755A8AD5@clickspace.com>
On Mon, Nov 27, 2006 at 07:23:47AM +0000, Brian Wipf wrote:
> On 26-Nov-06, at 11:25 PM, Jim C. Nasby wrote:
> >On Sat, Nov 18, 2006 at 08:13:26PM -0700, Brian Wipf wrote:
> >>It certainly is unfortunate if Guido's right and this is an upper
> >>limit for OS X. The performance benefit of having high shared_buffers
> >>on our mostly read database is remarkable.
> >
> >Got any data about that you can share? People have been wondering
> >about
> >cases where drastically increasing shared_buffers makes a difference.
>
> Unfortunately, there are more differences than just the
> shared_buffers setting in production right now; it's a completely
> different set up, so the numbers I have to compare against aren't
> particularly useful.
>
> When I get the chance, I will try to post data that shows the benefit
> of having a higher value of shared_buffers for our usage pattern
> (with all other settings being constant -- well, except maybe
> effective_cache_size). Basically, in our current configuration, we
> can cache all of the data we care about 99% of the time in about 3GB
> of shared_buffers. Having shared_buffers set to 512MB as it was
> originally, we were needlessly going to disk all of the time.
Disk or to the kernel cache?
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
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To: pgsql-performance@postgresql.org
Cc: jim@nasby.net, brian@clickspace.com, tgl@sss.pgh.pa.us, pg@fastcrypt.com, lists@event-s.net
Subject: Re: shared_buffers > 284263 on OS X
In-Reply-To: <20061127092256.GE67378@nasby.net>
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