From: Joshua D. Drake <jd@commandprompt.com>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: strange performance regression between 7.4 and 8.1
Date: Thu, 01 Mar 2007 12:50:24 -0800
Message-ID: <45E73C90.2080206@commandprompt.com> (raw)
In-Reply-To: <a728f9f90703011244r577d56d7y422ab4bd71bb760e@mail.gmail.com>
References: <a728f9f90703011244r577d56d7y422ab4bd71bb760e@mail.gmail.com>
Alex Deucher wrote:
> Hello,
>
> I have noticed a strange performance regression and I'm at a loss as
> to what's happening. We have a fairly large database (~16 GB). The
> original postgres 7.4 was running on a sun v880 with 4 CPUs and 8 GB
> of ram running Solaris on local scsi discs. The new server is a sun
> Opteron box with 4 cores, 8 GB of ram running postgres 8.1.4 on Linux
> (AMD64) on a 4 Gbps FC SAN volume. When we created the new database
> it was created from scratch rather than copying over the old one,
> however the table structure is almost identical (UTF8 on the new one
> vs. C on the old). The problem is queries are ~10x slower on the new
> hardware. I read several places that the SAN might be to blame, but
> testing with bonnie and dd indicates that the SAN is actually almost
> twice as fast as the scsi discs in the old sun server. I've tried
> adjusting just about every option in the postgres config file, but
> performance remains the same. Any ideas?
Vacuum? Analayze? default_statistics_target? How many shared_buffers?
effective_cache_size? work_mem?
Sincerely,
Joshua D. Drake
>
> Thanks,
>
> Alex
>
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To: pgsql-performance@postgresql.org
Cc: jd@commandprompt.com, alexdeucher@gmail.com
Subject: Re: strange performance regression between 7.4 and 8.1
In-Reply-To: <45E73C90.2080206@commandprompt.com>
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