> 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

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