Marinos Yannikos <> writes:
> we are seeing latency spikes in the 2-3 second range (sometimes 8-10s) for
> queries that usually take 3-4ms on our systems and I am running out of things to
> try to get rid of them.
Have you checked whether the spikes correlate with checkpoints? Turn
on log_checkpoints and watch for awhile. If so, fooling with the
checkpoint parameters might give some relief. However, 8.3 already has
the spread-checkpoint code so I'm not sure how much more win can be had
More generally, you should watch vmstat/iostat output and see if you
can correlate the spikes with I/O activity, CPU peaks, etc.
A different line of thought is that maybe the delays have to do with lock
contention --- log_lock_waits might help you identify that.
That's pretty scary.
Yipes. I don't think you have enough RAM for that to be safe.
> commit_delay=100000 (*)
This is probably not a good idea.
> autovacuum=off (*)
regards, tom lane