Date: Sun, 4 Nov 2007 19:33:46 -0500 (EST)
From: Greg Smith <gsmith@gregsmith.com>
To: pgsql-performance@postgresql.org
Subject: Migrating to 8.3 - checkpoints and background writer
Message-ID: <Pine.GSO.4.64.0711041912550.29985@westnet.com>
MIME-Version: 1.0
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For those of you considering a move to the upcoming 8.3 release, now in 
beta, I've written some documentation on the changes made in checkpoint 
and background writer configuration in the new version:

http://www.westnet.com/~gsmith/content/postgresql/chkp-bgw-83.htm

Since the first half of that covers the current behavior in 8.1 and 8.2, 
those sections may be helpful if you'd like to know more about checkpoint 
slowdowns and ways to resolve them even if you have no plans to evaluate 
8.3 yet.  I'd certainly encourage anyone who can run the 8.3 beta to 
consider adding some tests in this area while there's still time to 
correct any issues encountered before the official release.

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
http://j-davis.com/postgresql/syncscan/syncscan.pdf
http://j-davis.com/postgresql/syncscan/syncscan.odp

I particularly liked that first one because it gives a nice sample of how 
to generate large amounts of data easily and then run benchmarks against 
it, which is a handy thing to know for many types of performance 
comparisons.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD