Robert Haas <robertmh...@gmail.com> writes: > On Wed, Nov 23, 2011 at 1:30 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> What I think might make more sense is to keep two variables, >> RecentGlobalXmin with its current meaning and RecentDatabaseWideXmin >> which considers only xmins of transactions in the current database. >> Then HOT cleanup could select the appropriate cutoff depending on >> whether it's working on a shared or non-shared relation.
> Unfortunately, that would have the effect of lengthening the time for > which ProcArrayLock is held, and as benchmark results from Pavan's > patch in that area show, that makes a very big difference to total > throughput on write-heavy workloads. [ shrug... ] Simon's patch already adds nearly as many cycles in the hot spot as would be required to do what I suggest. 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