On Fri, Jan 13, 2012 at 12:27 PM, Fujii Masao <masao.fu...@gmail.com> wrote:
>> In my patch, the reason I avoided doing WRITE mode (which we had >> previously referred to as RECV) was that no fsync of the WAL contents >> takes place. In that case we are applying changes using un-fsynced WAL >> data and in case of crash this would cause a problem. > > My patch has not changed the execution order of WAL flush and replay. > WAL records are always replayed after they are flushed by walreceiver. > So, such a problem doesn't happen. > But which means that transaction might need to wait for WAL flush caused > by previous transaction even if WRITE mode is chosen. Which limits the > performance gain by WRITE mode, and should be improved later, I think. If the WALreceiver still flushes that is OK. The latency would be smoother and lower if the WALwriter were active. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
