Re: Exit walsender before confirming remote flush in logical replication

On Mon, Feb 2, 2026 at 4:56 PM Michael Paquier
<michael(at)paquier(dot)xyz> wrote:
 > Couldn't that be potentially dangerous, particularly if
 > wal_sender_shutdown_mode is set to immediate, meaning that it applies
 > to all the WAL senders?  The WAL receiver side could be on a backend
 > with an older backend version than the WAL sender where this new GUC
 > exists.

So far, I can't provide a scenario where the old-version receiving side is
having problems due to the behavior of immediate wal_sender_shutdown_mode.
Maybe someone else can.

Even if walsender immediate shutdown mode is set on the sender, it flushes
a done message to the receiver, as it is being done now. In the case 
when this
is not possible, it terminates in a similar way as it is currently doing
in WalSndShutdown(), the old receiver also seems to be able to handle this
case.

Regards,
Andrey Silitskiy