MIME-Version: 1.0
References: <Zwkk9Z6rzNxArr1p@ip-10-97-1-34.eu-west-3.compute.internal>
 <CAD21AoB31apHCzZ-45rDtB56qQm+TBwJnB48JjBvuqR5xviAEQ@mail.gmail.com>
 <CAD21AoD+opO0SaDSFvz+n+wAxc-kUrpF5Wtxbw80Bqpay+rkgw@mail.gmail.com>
 <CAHut+PsYdTW4+U+fioh9_yO8iT6RnY=PquzfCZu7zRU6Qg6W7g@mail.gmail.com>
 <Zwy4ys76aPcoVE/I@ip-10-97-1-34.eu-west-3.compute.internal>
 <CAD21AoDuO87MFrPJFwtmRi=cFhDGac0zq7sq5pdEhVi7zUvbEg@mail.gmail.com>
 <5qbxud4pvnvmtuoi7weiizm5hmumxaeohx4vztfhrwlfhyz6rj@buh4435mllwo>
 <CAD21AoBM6vAcPGR-ng0nqGG0yemR_ufdg3+v3gkPa6Nc2ntnrA@mail.gmail.com>
 <Z8f6dQPR67ahM2DN@ip-10-97-1-34.eu-west-3.compute.internal>
 <CAA4eK1L0bZbZOr8-VNFXDfqaTwggdf_-HTAsneui+_ozMTvZQg@mail.gmail.com>
 <Z8g9/GeoXv/gIL60@ip-10-97-1-34.eu-west-3.compute.internal>
 <CAD21AoBkdiq6Te7D_LtKDDB2WsZWBKWqWNVguhy9R_xAMf_xDg@mail.gmail.com>
In-Reply-To: 
 <CAD21AoBkdiq6Te7D_LtKDDB2WsZWBKWqWNVguhy9R_xAMf_xDg@mail.gmail.com>
From: Amit Kapila <amit.kapila16@gmail.com>
Date: Fri, 7 Mar 2025 10:26:23 +0530
Message-ID: 
 <CAA4eK1LGV8PME4KfZanF16gE1HDb+nPn06TTxv1OtV0466oJ-w@mail.gmail.com>
Subject: Re: Add contrib/pg_logicalsnapinspect
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>,
 Andres Freund <andres@anarazel.de>,
	Peter Smith <smithpb2250@gmail.com>, Peter Eisentraut <peter@eisentraut.org>,
	shveta malik <shveta.malik@gmail.com>,
	Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
 pgsql-hackers@lists.postgresql.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: 
 <https://www.postgresql.org/message-id/CAA4eK1LGV8PME4KfZanF16gE1HDb%2BnPn06TTxv1OtV0466oJ-w%40mail.gmail.com>
Precedence: bulk

On Fri, Mar 7, 2025 at 3:19=E2=80=AFAM Masahiko Sawada <sawada.mshk@gmail.c=
om> wrote:
>
> On Wed, Mar 5, 2025 at 4:05=E2=80=AFAM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> >
> > Hi,
> >
> > On Wed, Mar 05, 2025 at 02:42:15PM +0530, Amit Kapila wrote:
> > > On Wed, Mar 5, 2025 at 12:47=E2=80=AFPM Bertrand Drouvot
> > > <bertranddrouvot.pg@gmail.com> wrote:
> > > >
> > > > Agree, PFA a patch doing so.
> > > >
> > >
> > > It would be better if you could add a few comments atop the
> > > permutation line to explain the working of the test.
> >
> > yeah makes sense. Done in the attached, and bonus point I realized that=
 the
> > test could be simplified (so, removing useless steps in passing).
> >
>
> Thank you for the patch.
>
> The new simplified test case can be pretty-formatted as:
>
> init
> begin
> savepoint
> truncate
>                 checkpoint-1
>                 get_changes-1
> commit
>                 checkpoint-2
>                 get_changes-2
>                 info_catchange check
>                 info_committed check
>                 meta check
>
> IIUC if another checkpoint happens between get_change-2 and the
> subsequent checks, the first snapshot would be removed during the
> checkpoint, resulting in a test failure. I think we could check the
> snapshot files while one transaction keeps open. The more simplified
> test case would be:
>
> init
> begin
> savepoint
> insert(cat-change)
>                 begin
>                 insert(cat-change)
>                 commit
>                 checkpoint
>                 get_changes
>                 info_catchange check
>                 info_committed check
>                 meta check
> commit
>
> In this test case, we would have at least one serialized snapshot that
> has both cat-changes and committed txns. What do you think?
>

Your proposed change in the test sounds better than what we have now
but I think we should also avoid autovacuum to perform analyze as that
may add additional counts. For test_decoding, we keep
autovacuum_naptime =3D 1d in logical.conf file, we can either use the
same here or simply keep autovacuum off.

--=20
With Regards,
Amit Kapila.