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