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

On Fri, Sep 22, 2023 at 10:57 AM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> On Thu, Sep 21, 2023 at 5:45 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > > Thanks for the patch. I have some comments on v42:
> >
> > Probably trying to keep it similar with
> > binary_upgrade_create_empty_extension(). I think it depends what
> > behaviour we expect for NULL input.
>
> confirmed_flush_lsn for a logical slot can be null (for instance,
> before confirmed_flush is updated for a newly created logical slot if
> someone calls pg_stat_replication -> pg_get_replication_slots) and
> when it is so, the binary_upgrade_create_empty_extension errors out.
> Is this behaviour wanted? I think the function returning null on null
> input is a better behaviour here.
>

I think if we do return null on null behavior then the caller needs to
add a special case for null value as this function returns bool. We
can probably return false in that case. Does that help to address your
concern?

--
With Regards,
Amit Kapila.