We just installed performance monitoring on our web application, and we're seeing a spiky pattern in response times from our Postgres 8.4 server. The spikes correspond with significant slowdown in our web app. The time seems to taken up largely in "Postgres commit":
We're self-hosting Postgres 8.4.3 on Ubuntu 10.04, with essentially stock settings, on an Amazon EC2 c1.xlarge instance w/ EBS. Yes, I know that Postgres on EBS probably isn't the best setup. We plan to move to a newer Postgres DB on RDS later this year.
In the meantime, is there anything obvious that I should look at that might tame this spiky pattern?