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

Hi,

On 6/5/20 11:51 AM, Alvaro Herrera wrote:
> On 2020-Jun-05, Dave Cramer wrote:
> 
>> On Thu, 4 Jun 2020 at 19:46, Alvaro Herrera <alvherre@2ndquadrant.com>
>> wrote:
> 
>>> Ouch ... so they made IDENT in the replication grammar be a trigger to
>>> enter the regular grammar.  Crazy.  No way to put those worms back in
>>> the tin now, I guess.
>>
>> Is that documented ?
> 
> I don't think it is.
> 
>>> It is still my opinion that we should prohibit a logical replication
>>> connection from being used to do physical replication.  Horiguchi-san,
>>> Sawada-san and Masao-san are all of the same opinion.  Dave Cramer (of
>>> the JDBC team) is not opposed to the change -- he says they're just
>>> using it because they didn't realize they should be doing differently.
>>
>> I think my exact words were
>>
>> "I don't see this is a valid reason to keep doing something. If it is
>> broken then fix it.
>> Clients can deal with the change."
>>
>> in response to:
>>
>>> Well, I don't really think that we can just break a behavior that
>>> exists since 9.4 as you could break applications relying on the
>>> existing behavior, and that's also the point of Vladimir upthread.
>>
>> Which is different than not being opposed to the change. I don't see this
>> as broken, and it's quite possible that some of our users are using
>> it.
> 
> Apologies for misinterpreting.
> 
>> It certainly needs to be documented
> 
> I'd rather not.

The PG13 RMT had a discussion about this thread, and while the initial
crash has been fixed, we decided to re-open the Open Item around whether
we should allow physical replication to be initiated in a logical
replication session.

We anticipate a resolution for PG13, whether it is explicitly
disallowing physical replication from occurring on a logical replication
slot, maintaining the status quo, or something else such that there is
consensus on the approach.

Thanks,

Jonathan