Re: Can anyone explain this pgbench results?

On Mon, Mar 06, 2006 at 04:29:49PM +0100, Joost Kraaijeveld wrote:
> Below are some results of running pgbench, run on a machine that
> is doing nothing else than running PostgreSQL woth pgbench. The
> strange thing is that the results are *constantly alternating* hight
> (750-850 transactions)and low (50-80 transactions), no matter how
> many test I run. If I wait a long time (> 5 minutes) after running
> the test, I always get a hight score, followed by a low one, followed
> by a high one, low one etc.

The default checkpoint_timeout is 300 seconds (5 minutes).  Is it
coincidence that the "long time" between fast results is about the
same?  What's your setting?  Are your test results more consistent
if you execute CHECKPOINT between them?

--
Michael Fuhr