Date: Fri, 7 Aug 2020 19:18:29 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Cc: ashutosh.bapat@2ndquadrant.com, Noah Misch <noah@leadboat.com>
Subject: Re: walsender waiting_for_ping spuriously set
Message-ID: <20200807231829.GA3040@alvherre.pgsql>
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On 2020-Aug-07, Alvaro Herrera wrote:

> I'm thinking in keeping the sentences that were added in that commit,
> maybe like so:
> 
> >  		 * We only send regular messages to the client for full decoded
> >  		 * transactions, but a synchronous replication and walsender shutdown
> >  		 * possibly are waiting for a later location. So, before sleeping, we
> > +		 * send a ping containing the flush location. A reply from standby is
> > +		 * not needed and would be wasteful most of the time,
> > +		 * but if the receiver is otherwise idle and walreceiver status messages
> > +		 * are enabled, this keepalive will trigger a reply.  Processing the
> > +		 * reply will update these MyWalSnd locations.

After rereading this a few more times, I think it's OK as Noah had it,
so I'll just use his wording.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services