On 2014-02-14 13:58:59 +0100, Andres Freund wrote: > On 2014-02-14 12:55:06 +0000, Greg Stark wrote: > > On Fri, Feb 14, 2014 at 12:05 PM, Andres Freund <and...@2ndquadrant.com> > > wrote: > > > There's no reason not > > > to ask for a ping when we're writing. > > > Is there a reason to ask for a ping? The point of keepalives is to > > ensure there's some traffic on idle connections so that if the > > connection is dead it doesn't linger forever and so that any on-demand > > links (or more recently NAT routers or stateful firewalls) don't time > > out and disconnect and have to reconnect (or more recently just fail > > outright). > > This ain't TCP keepalives. The reason is that we want to kill walsenders > if they haven't responded to a ping inside wal_sender_timeout. That's > rather important e.g. for sychronous replication, so we can quickly fall > over to the next standby. In such scenarios you'll usually want a > timeout *far* below anything TCP provides.
walreceiver sends pings everytime it receives a 'w' message, so it's probably not an issue there, but pg_receivexlog/basebackup don't; they use their own configured intervarl. So this might be an explanation of the latter two being disconnected too early. I've seen reports of that... Greetings, Andres Freund -- Andres Freund 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
