Robert Haas <robertmh...@gmail.com> writes: > On Mon, Oct 11, 2010 at 10:14 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Reduction of contention for pg_clog access, for one thing. If you read >> the archives, you'll find that pg_clog access contention has been shown >> to be one cause of "context swap storms".
> I wonder if we could improve this with some sort of process-local > cache - not to get rid of hint bits, just to reduce pg_clog > contention. We might easily end up testing the same XID many times > during the same table scan. There already is a one-entry cache --- see TransactionLogFetch. Not sure if making it bigger would be a win in current usage, although you'd likely have to if you were trying to not set hint bits. > Another idea that's been discussed before is to avoid writing out > pages when only the hit bints have changed. Yeah. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers