On 2020-Sep-30, Tom Lane wrote:
> Henry Hinze <henry.hinze@gmail.com> writes:
> > I've made an important observation!
> > Since I had the impression this setup was already working with RC1 of PG
> > 13, I re-installed RC1 and did the same test. And it's working fine!
>
> Ugh. So that points the finger at commits 07082b08c/bfb12cd2b,
> which are the only nearby change between rc1 and 13.0. A quick
> comparison of before-and-after checkouts confirms it.
Oh dear.
> After some digging around, I realize that that commit actually
> resulted in a protocol break. libpqwalreceiver is expecting to
> get an additional CommandComplete message after COPY OUT finishes,
> per libpqrcv_endstreaming(), and it's no longer getting one.
>
> (I have not read the protocol document to see if this is per spec;
> but spec or no, that's what libpqwalreceiver is expecting.)
Yeah, definitely.
The minimal fix seems to be to add an EndReplicationCommand() call in
the T_StartReplicationCmd case. Testing this now ...
> The question that this raises is how the heck did that get past
> our test suites? It seems like the error should have been obvious
> to even the most minimal testing.
... yeah, that's indeed an important question. I'm going to guess that
the TAP suites are too forgiving :-(