So, our drop in performance is now clearly due to pathological OS behavior during checkpoints. Still trying to pin down what's going on, but it's not system load; it's clearly related to the IO system. Anyone else see this? I'm getting it both on 3.2 and 3.4. We're using LSI Megaraid. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance