On Thu, Jan 5, 2012 at 2:57 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > I would be in favor of that, or perhaps some other formula (eg, maybe > the minimum should be less than 8 for when you've got very little shmem).
I have some results that show that, under the right set of circumstances, 8->32 is a win, and I can quantify by how much it wins. I don't have any data at all to quantify the cost of dropping the minimum from 8->6, or from 8->4, and therefore I'm reluctant to do it. My guess is that it's a bad idea, anyway. Even on a system where shared_buffers is just 8MB, we have 1024 regular buffers and 8 CLOG buffers. If we reduce the number of CLOG buffers from 8 to 4 (i.e. by 50%), we can increase the number of regular buffers from 1024 to 1028 (i.e. by <0.5%). Maybe you can find a case where that comes out to a win, but you might have to look pretty hard. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
