Radoslav Nedyalkov <rnedyalkov@gmail.com> writes:
> If the target is upgraded to pg13 then the initial copy goes fine.
> Unfortunately it is a 40T db in a sunset, so we'd rather won't upgrade.
Yeah, after looking at the code, pre-v13 versions simply don't know
how to do initial sync from anything except a plain table. The changes
involved in that were significant enough that nobody is going to be
on board with back-patching them.
The wording of this error message is pretty confusing though.
I think it might be reasonable to change the back branches so
that they report something like "can't sync from a non-table"
rather than claiming the object doesn't exist at all.
regards, tom lane