> Hmmm, I've not seen this. For example, with people who are having trouble > with checkpoint spikes on Linux, I've taken to recommending that they call > sync() (via cron) every 5-10 seconds (thanks, Bruce, for suggestion!). > Believe it or not, this does help smooth out the spikes and give better > overall performance in a many-small-writes situation.
The reason is imho that the checkpoint otherwise also syncs all other writes. These can be writes other backends had to do to replace a buffer. Linux obviously lacks a mechanism to distribute the IO for cached writes over time ala bgwriter (or does not do it when already faced with an IO bottleneck). Andreas ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match