From: Tom Lane <tgl@sss.pgh.pa.us>
To: Patric de Waha <lists@p-dw.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Two questions.. shared_buffers and long reader issue
Date: Wed, 11 Jul 2007 12:57:42 -0400
Message-ID: <27288.1184173062@sss.pgh.pa.us> (raw)
In-Reply-To: <4694F8C5.2040005@p-dw.com>
References: <4694F8C5.2040005@p-dw.com>
Patric de Waha <lists@p-dw.com> writes:
> Postgres is running on a dedicated server P4 DualCore, 4 Gig Ram.
When you don't even mention your disk hardware, that's a bad sign.
In a database server the disk is usually more important than the CPU.
> Why do long readers influence the rest of the transactions in such a
> heavy way?
> Any configuration changes which can help here?
> Is it a disc-IO bottleneck thing?
Very possibly. Have you spent any time watching "vmstat 1" output
to get a sense of whether your I/O is saturated?
> WAL files are located on another disc than the dbase itself.
That's good, but it only relates to update performance not SELECT
performance.
> effective_cache_size = 5000
That's way too small for a 4G machine. You could probably stand to
boost maintenance_work_mem too. However, neither of these have any
immediate relationship to your problem.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, lists@p-dw.com
Subject: Re: Two questions.. shared_buffers and long reader issue
In-Reply-To: <27288.1184173062@sss.pgh.pa.us>
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