On Mon, Jan 23, 2012 at 11:01 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Mon, Jan 23, 2012 at 12:12 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>>> The expensive part of what >>>> we do while holding BufFreelistLock is, I think, iterating through >>>> buffers taking and releasing a spinlock on each one (!). > >>> Yeah ... spinlocks that, by definition, will be uncontested. > >> What makes you think that they are uncontested? > > Ah, never mind. I was thinking that we'd only be touching buffers that > were *on* the freelist, but of course this is incorrect. The real > problem there is that BufFreelistLock is also used to protect the > clock sweep pointer. I think basically we gotta find a way to allow > multiple backends to run clock sweeps concurrently. Or else fix > things so that the freelist never (well, hardly ever) runs dry.
I'd come to the same conclusion myself. :-) -- 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
