On 2018-03-31 22:13:42 +0800, Craig Ringer wrote:
> We'll still need a mechanism to transport them to downstreams (like WAL
> messages) and to send responses upstream. For responses I think we will
> finally want to add a backchannel to the logical replication protocol as
> I've wanted for a long while: downstream can send a COPY message on COPY
> BOTH proto back to upstream, which passes it to a callback on the output
> plugin for the output plugin to act on.
Not necessarily? You can just send out the prepare, wait for all
clients to ack it, and then commit/rollback prepared.
Greetings,
Andres Freund