Hi,
I had some trouble today with a misbehaving logical replication client
which had confirmed a flush of an LSN far into the future. Debugging it
was a bit of a pain for a number of reasons, but I think the most
important one was that confirmed_flush isn't exposed in
pg_stat_replication_slots. Attached patch exposes it, as
confirmed_flush_lsn (to make it look like restart_lsn; not sure whether
we should just keep the internal name or not).
Adding this one to the next commit fest, but any feedback welcome in the
meanwhile.
.m