On Thu, May 31, 2012 at 11:50 AM, Robert Haas <robertmh...@gmail.com> wrote: > > This test case is unusual because it hits a whole series of buffers > very hard. However, there are other cases where this happens on a > single buffer that is just very, very hot, like the root block of a > btree index, where the pin/unpin overhead hurts us.
I think that very very hot page is also the problem here, not a whole sequence of hot pages. Most of his buffer content sh lwlocks are on just two buffers, and most of his blocked buffer mapping lwlocks on are on just two partitions. So I am guessing that almost all of his spin-lock contention from Pin and Unpin are also coming from those same two buffers. Why there are two buffers when there is only one index root block involved, I don't know. Cheers, Jeff -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
