From: Jonathan S. Katz <jkatz@postgresql.org>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Dave Cramer <davecramer@postgres.rocks>
Cc: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Cc: Peter Geoghegan <pg@bowt.ie>
Subject: Re: SIGSEGV from START_REPLICATION 0/XXXXXXX in XLogSendPhysical () at walsender.c:2762
Date: Sun, 21 Jun 2020 13:45:36 -0400
Message-ID: <69edce5b-c5a4-6b1a-fe2f-9e53d1e0d19f@postgresql.org> (raw)
In-Reply-To: <20200605155148.GA19795@alvherre.pgsql>
References: <20200605155148.GA19795@alvherre.pgsql>
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
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Cc: jkatz@postgresql.org, alvherre@2ndquadrant.com, davecramer@postgres.rocks, andres@anarazel.de, michael@paquier.xyz, masao.fujii@oss.nttdata.com, masahiko.sawada@2ndquadrant.com, horikyota.ntt@gmail.com, sitnikov.vladimir@gmail.com, pg@bowt.ie
Subject: Re: SIGSEGV from START_REPLICATION 0/XXXXXXX in XLogSendPhysical () at walsender.c:2762
In-Reply-To: <69edce5b-c5a4-6b1a-fe2f-9e53d1e0d19f@postgresql.org>
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