From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: Migrating to 8.3 - checkpoints and background writer
Date: Mon, 5 Nov 2007 01:39:48 +0100
Message-ID: <20071105003948.GA25351@uio.no> (raw)
In-Reply-To: <Pine.GSO.4.64.0711041912550.29985@westnet.com>
References: <Pine.GSO.4.64.0711041912550.29985@westnet.com>
On Sun, Nov 04, 2007 at 07:33:46PM -0500, Greg Smith wrote:
> On the topic of performance improvements in 8.3, I don't think this list
> has been getting information about the concurrent sequential scans
> improvements. Check out these documents for more about that:
>
> http://j-davis.com/postgresql/83v82_scans.html
That's a nice writeup. I'm a bit puzzled by this part, though: "All tests
are on linux with the anticipatory I/O scheduler. The default I/O scheduler
for Linux is CFQ (Completely Fair Queue), which does not work well for
PostgreSQL in my tests."
All earlier benchmarks I've seen (even specifically for Postgres) have said
that cfq > deadline > anticipatory for database work. How large was the
difference for you?
/* Steinar */
--
Homepage: http://www.sesse.net/
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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com
Subject: Re: Migrating to 8.3 - checkpoints and background writer
In-Reply-To: <20071105003948.GA25351@uio.no>
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