On Mon, Oct 04, 2004 at 02:42:43PM -0400, Greg Stark wrote: > Mark Wong <[EMAIL PROTECTED]> writes: > > > Links to results are here: > > 7.5devel - http://www.osdl.org/projects/dbt2dev/results/dev4-010/128/ > > 8.0beta3 - http://www.osdl.org/projects/dbt2dev/results/dev4-010/180/ > > Are those cyclic spikes an artifact of the load of the tests? Or are they > artifacts of the postgres checkpoint process? > > If they're an artifact of the test is it possible to randomize the number > iterations and time each connection does before issuing the slower queries? Or > somehow avoid generating these spikes? > > If they're an artifact of the checkpoint process I wonder if there are > parameters that can be tweaked to smooth it out more. Some of those > transactions/second drops are quite dramatic. It seems like you're averaging > 200 txn/s normally but having it drop down to less than half that > periodically. >
In the past, they have been artifacts of the checkpoint process. They do smooth out as I increase the checkpoint segments and the timeout. Although I know that doesn't exactly exclude other explanations. There are 5000 emulated clients connected through 100 database connections for both of those tests, attempting 1 of 5 different transactions. I hope that's random enough. :) When I run a less intense workload, everything smooths out a bit more too but it doesn't stress the system nearly as much. Mark ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])