From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ryan Wexler <ryan@iridiumsuite.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: performance on new linux box
Date: Wed, 07 Jul 2010 20:39:16 -0400
Message-ID: <11690.1278549556@sss.pgh.pa.us> (raw)
In-Reply-To: <AANLkTinVrej5r_uF3As3mF8BW4CYgLGiw2-v2HORsqjM@mail.gmail.com>
References: <AANLkTinVrej5r_uF3As3mF8BW4CYgLGiw2-v2HORsqjM@mail.gmail.com>
Ryan Wexler <ryan@iridiumsuite.com> writes:
> Postgresql was previously running on a single cpu linux machine with 2 gigs
> of memory and a single sata drive (v8.3). Basically a desktop with linux on
> it. I experienced slow performance.
> So, I finally moved it to a real server. A dually zeon centos machine with
> 6 gigs of memory and raid 10, postgres 8.4. But, I am now experiencing even
> worse performance issues.
I'm wondering if you moved to a kernel+filesystem version that actually
enforces fsync, from one that didn't. If so, the apparently faster
performance on the old box was being obtained at the cost of (lack of)
crash safety. That probably goes double for your windows-box comparison
point.
You could try test_fsync from the Postgres sources to confirm that
theory, or do some pgbench benchmarking to have more quantifiable
numbers.
See past discussions about write barriers in this list's archives for
more detail.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, ryan@iridiumsuite.com
Subject: Re: performance on new linux box
In-Reply-To: <11690.1278549556@sss.pgh.pa.us>
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