Re: [PoC] pg_upgrade: allow to upgrade publisher node

On Thu, Sep 21, 2023 at 1:10 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> On Wed, Sep 20, 2023 at 11:28:33AM +0000, Hayato Kuroda (Fujitsu) wrote:
> > Good catch, I could not notice because it worked well in my RHEL. Here is the
> > updated version.
>
> I am getting slowly up to date with this patch.. But before going in
> depth with more review, there is something that I got to ask: why is
> there no option to control if the slots are copied across the upgrade?
> At least, I would have imagined that an option to disable the copy of
> the slots would be adapted, say a --no-slot-copy or similar to get
> back to the old behavior if need be.
>

We have discussed this point. Normally, we don't have such options in
upgrade, so we were hesitent to add a new one for this but there is a
discussion to add an --exclude-logical-slots option. We are planning
to add that as a separate patch after getting some more consensus on
it. Right now, the idea is to get the main patch ready.

> + * This is because before that the logical slots are not saved at shutdown, so
> + * there is no guarantee that the latest confirmed_flush_lsn is saved to disk
>
> Is this comment in get_old_cluster_logical_slot_infos() still true
> after e0b2eed047d?
>

Yes, we didn't backpatched it, so slots from pre-17 won't be flushed
at shutdown time even if required.

--
With Regards,
Amit Kapila.