Alvaro Herrera wrote:
BTW the only reason you don't see buffers having a larger "usage" is that the counters are capped at that value.
Right, the usage count is limited to 5 for no reason besides "that seems like a good number". We keep hoping to come across a data set and application with a repeatable benchmark where most of the data ends up at 5, but there's still a lot of buffer cache churn, to allow testing whether a further increase could be valuable. So far nobody has actually found such a set. If I shrunk shared_buffers on Ben's data I think I could create that situation. As is usually the case, I doubt he has another server with 128GB of RAM hanging around just to run that experiment on though, which has always been the reason why I can't simulate this more easily--systems it's prone to happening on aren't cheap.
-- Greg Smith 2ndQuadrant US Baltimore, MD PostgreSQL Training, Services and Support greg@xxxxxxxxxxxxxxx www.2ndQuadrant.us -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
