Marinos Yannikos <mjy@xxxxxxxxxxx> 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 there. 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. > fsync=off That's pretty scary. > work_mem=500MB 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 (*) Nor this. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
