From: Tom Lane <tgl@sss.pgh.pa.us>
To: tsuraan <tsuraan@gmail.com>
Cc: Greg Smith <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Scaling concerns
Date: Sun, 17 Dec 2006 23:59:12 -0500
Message-ID: <21940.1166417952@sss.pgh.pa.us> (raw)
In-Reply-To: <84fb38e30612172036s74183c5ey930eb4f608578f81@mail.gmail.com>
References: <84fb38e30612160926l609ec55cs352b2495289bae0c@mail.gmail.com>
<20061217032527.GL29195@andi-lap.la.revver.com>
<84fb38e30612171359r6288de69y2553be256019ba4b@mail.gmail.com>
<Pine.GSO.4.64.0612171856150.17147@westnet.com>
<84fb38e30612172036s74183c5ey930eb4f608578f81@mail.gmail.com>
tsuraan <tsuraan@gmail.com> writes:
> Is the WAL at the same location as the xlog (transaction log?)?
Same thing.
> The checkpoint_segments doc says increasing that value is really only
> useful if the xlog is separate from the data,
Dunno where you read that, but it's utter bilge. If you've got a
write-intensive workload, you want to crank checkpoint_segments as high
as you can stand. With the default settings on a modern machine it's
not hard at all to push it into checkpointing every dozen or seconds,
which will completely kill performance. (Disk space for pg_xlog/ and
potential delay during crash restart are the only negatives here. If
you are willing to push the average inter-checkpoint interval past five
minutes then you need to increase checkpoint_timeout too.)
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, tsuraan@gmail.com, gsmith@gregsmith.com
Subject: Re: Scaling concerns
In-Reply-To: <21940.1166417952@sss.pgh.pa.us>
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