On Fri, May 24, 2013 at 10:36 AM, Jim Nasby <j...@nasby.net> wrote: > Doesn't that hit the old issue of not knowing if a read came from FS cache > or disk? I realize that the current cost_delay mechanism suffers from that > too, but since the API is lower level that restriction is much more > apparent.
Sure, but I think it's still useful despite that limitation. > Instead of KB/s, could we look at how much time one process is spending > waiting on IO vs the rest of the cluster? Is it reasonable for us to measure > IO wait time for every request, at least on the most popular OSes? I doubt that's going to be very meaningful. The backend that dirties the buffer is fairly likely to be different from the backend that writes it out. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers