Matthew Wakeling wrote:
Does your latency graph really have milliseconds as the y axis? If so, this device is really slow - some requests have a latency of more than a second!
Have you tried that yourself? If you generate one of those with standard hard drives and a BBWC under Linux, I expect you'll discover those latencies to be >5 seconds long. I recently saw >100 *seconds* running a large pgbench test due to latency flushing things to disk, on a system with 72GB of RAM. Takes a long time to flush >3GB of random I/O out to disk when the kernel will happily cache that many writes until checkpoint time.
-- Greg Smith 2ndQuadrant US Baltimore, MD PostgreSQL Training, Services and Support g...@2ndquadrant.com www.2ndQuadrant.us -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
