On Thu, 2010-05-27 at 19:21 +0900, Fujii Masao wrote: > On Thu, May 27, 2010 at 6:30 PM, Simon Riggs <si...@2ndquadrant.com> wrote:
> > Would it be easier to have > > this happen in a second pair of processes WALSynchroniser (on primary) > > and WAL Acknowledger (on standby). WALAcknowledger would send back a > > stream of ack messages with latest xlog positions. WALSynchroniser would > > receive these messages and wake up sleeping backends. If we did that > > then there'd be almost no change at all to existing code, just > > additional code and processes for the sync case. Code would be separate > > and there would be no performance concerns either. > > No, this seems to be bad idea. We should not establish extra connection > between servers. That would be a source of trouble. What kind of trouble? You think using an extra connection would cause problems; why? I've explained it would greatly simplify the code to do it that way and improve performance. Those sound like good things, not problems. > > If you do choose to make #3 important, then I'd say you need to work out > > how to make WALWriter active as well, so it can perform regular fsyncs, > > rather than having WALReceiver wait across that I/O. > > Yeah, this might be an option for optimization though I'm not sure how > it has good effect. As I said, WALreceiver would not need to wait across fsync... -- Simon Riggs www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers