Re: logical copy_replication_slot issues

On Mon, 10 Feb 2020 at 23:01, Arseny Sher <a(dot)sher(at)postgrespro(dot)ru> wrote:
>
>
> Masahiko Sawada <masahiko(dot)sawada(at)2ndquadrant(dot)com> writes:
>
> > I've attached the draft patch fixing this issue but I'll continue
> > investigating it more deeply.
>
> There also should be a check that source slot itself has consistent
> snapshot (valid confirmed_flush) -- otherwise it might be possible to
> create not initialized slot which is probably not an error, but weird
> and somewhat meaningless. Paranoically, this ought to be checked in both
> src slot lookups.
>
> With this patch it seems like the only thing
> create_logical_replication_slot does is ReplicationSlotCreate, which
> questions the usefulness of this function. On the second look,
> CreateInitDecodingContext checks plugin sanity (ensures it exists), so
> probably it's fine.
>

Thank you for reviewing this patch.

I've attached the updated version patch that incorporated your
comments. I believe we're going in the right direction for fixing this
bug. I'll register this item to the next commit fest so as not to
forget.

Regards,

--
Masahiko Sawada http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services