[...] Sorry for the late reply. This patch only supports logical decoding from standby. So it's just an infrastructure for supporting logical replication from standby. We don't support creating a publication from standby, but the publication on master is replicated on standby, so we might be able to create subscription nodes that connect to existing publications on standby, but basically we haven't tested whether the publication/subscription model works with a publication on a physical standby. This patch is focussed on providing a way to continue logical replication *after* the standby is promoted as master.
