Re: Xeon vs Opteron - second revision - tests and questions

Marcin Giedz <marcin(dot)giedz(at)eulerhermes(dot)pl> writes:
> However I still can see 'spikey' performance but not as much as before
> changes. What can I do more to eliminate or smooth these spikes?

The spikes are certainly caused by checkpoints. You can fool with the
checkpoint timing via checkpoint_segments and checkpoint_timeout.
Usually people put them as far apart as they can stand (the constraint
on this is mainly how long you'd like to wait for recovery after a
system crash, and how much disk space you can spare for WAL logs).
Increasing the bg_writer parameters can be expected to dampen the spikes
but not eliminate them completely.

regards, tom lane