From: Antonin Houska <ah@cybertec.at>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
cc: Andres Freund <andres@anarazel.de>,
    pgsql-hackers@lists.postgresql.org
Subject: Re: Race conditions in logical decoding
In-reply-to: 
 <CADzfLwWbawF1pE2fHDXR2O3rdY54v43mRJmOK4pDGWgzAmXwkw@mail.gmail.com>
References: <85833.1768840165@localhost> <62335.1768897833@localhost>
 <5k2dfckyp6zv2fiovosvtbya5onvplgviz5n4kdamxupff4vi2@yytzfnwr2ox7>
 <CADzfLwWbawF1pE2fHDXR2O3rdY54v43mRJmOK4pDGWgzAmXwkw@mail.gmail.com>
Comments: In-reply-to Mihail Nikalayeu <mihailnikalayeu@gmail.com>
   message dated "Thu, 22 Jan 2026 01:24:43 +0100."
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Date: Thu, 22 Jan 2026 11:32:58 +0100
Message-ID: <124728.1769077978@localhost>
Archived-At: 
 <https://www.postgresql.org/message-id/124728.1769077978%40localhost>
Precedence: bulk

Mihail Nikalayeu <mihailnikalayeu@gmail.com> wrote:

> Hello, Andres.
>=20
> On Tue, Jan 20, 2026 at 6:50=E2=80=AFPM Andres Freund <andres@anarazel.de=
> wrote:
> > I don't think that's enough - during non-timetravel visibility semantic=
s, you
> > can only look at the clog if the transaction isn't marked as in-progres=
s in
> > the procarray.  ISTM that we need to do that here too?
>=20
> Do you mean replace
> > if (unlikely(!TransactionIdDidCommit(builder->committed.xip[i])))
> to
> > if (unlikely(TransactionIdIsInProgress(builder->committed.xip[i]) || !T=
ransactionIdDidCommit(builder->committed.xip[i])))

This way the synchronous replication gets stuck, as it did when I tried to =
use
XactLockTableWait(): subscriber cannot confirm replication of certain LSN
because publisher is not able to even finalize the commit (due to the waiti=
ng
for the subscriber's confirmation), and therefore publisher it's not able to
decode the data and send it to the subscriber.

--=20
Antonin Houska
Web: https://www.cybertec-postgresql.com