Re: Draft back-branch release notes are up

Hi,

On Mon, Nov 09, 2026 at 11:34:12AM +0530, Amit Kapila wrote:
> On Mon, Nov 9, 2026 at 11:11 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >
> > Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> writes:
> > > On Sun, Nov 8, 2026 at 9:37 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > >> Hmph. I read that and I was like "so what?". Why would users need
> > >> to know that? How likely is it that anyone would issue such a
> > >> combined command in the first place?
> >
> > > I agree that it is less likely for users to use such a combination and
> > > even if they use I don't think it is a big deal. We can leave
> > > mentioning anything about such a combination.
> >
> > To be clear, that was an honest request for information. I don't
> > understand why this point is worth space in the release notes.
> > But if you think it is, educate me. We still have a little time
> > to adjust the notes ...
> >
>
> This was an unintended behavior (resetting slot's two_phase property
> when user tries to mark two_phase for a subscription where two_phase
> was already set) which was previously working and has the risk of the
> same bugs as noted in the commit message. I don't know if in practice
> any one would be using such a combination, so it is not clear to me if
> there is a need to mention it in release notes. We can wait and see if
> Bertrand has any thoughts on the same.

Even if this combination is uncommon, what worried me, is that a user relying on
the previous behavior would *silently* use the replacement slot without two phase
decoding. My thought was that mentioning this in the release notes would at least
make the behavior change less likely to go unnoticed.

Maybe we could shorten the sentence, something like:

"
Users issuing ALTER SUBSCRIPTION ... SET (slot_name = ..., two_phase = true) must
ensure that the replacement slot already has two_phase enabled, as the apply worker
no longer enables it automatically.
"

That said, if you and others don't think it is worth mentioning, I'm fine with
leaving it out (as the doc already describes that the replacement slot's
properties must match the subscription options).

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com