Re: SIGSEGV from START_REPLICATION 0/XXXXXXX in XLogSendPhysical () at walsender.c:2762

At Thu, 28 May 2020 09:08:19 -0400, Dave Cramer <davecramer@postgres.rocks> wrote in 
> On Thu, 28 May 2020 at 05:11, Kyotaro Horiguchi <horikyota.ntt@gmail.com>
> wrote:
> > Mmm. It is not the proper way to use physical replication and it's
> > totally accidental that that worked (or even it might be a bug). The
> > documentation is saying as the follows, as more-or-less the same for
> > all versions since 9.4.
> >
> > https://www.postgresql.org/docs/13/protocol-replication.html
...
> >
> While the documentation does indeed say that there is quite a bit of
> additional confusion added by:
> 
> and
> START_REPLICATION [ SLOT *slot_name* ] [ PHYSICAL ] *XXX/XXX* [ TIMELINE
> *tli* ]
> 
> If we already have a physical replication slot according to the startup
> message why do we need to specify it in the START REPLICATION message ?

I don't know, but physical replication has worked that way since
before the replication slots was introduced so we haven't needed to do
so.  Physical replication slots are not assumed as more than
memorandum for the oldest required WAL segment (and oldest xmin).

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center