Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, vignesh C <vignesh21@gmail.com>
Date: 2023-08-10T05:26:49Z
Lists: pgsql-hackers 
On Mon, Aug 7, 2023 at 3:46 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Mon, Aug 7, 2023 at 1:06 PM Julien Rouhaud <rjuju123@gmail.com> wrote:
> >
> > On Mon, Aug 07, 2023 at 12:42:33PM +0530, Amit Kapila wrote:
> > > On Mon, Aug 7, 2023 at 11:29 AM Julien Rouhaud <rjuju123@gmail.com> wrote:
> > > >
> > > > Unless I'm missing something I don't see what prevents something to connect
> > > > using the replication protocol and issue any query or even create new
> > > > replication slots?
> > > >
> > >
> > > I think the point is that if we have any slots where we have not
> > > consumed the pending WAL (other than the expected like
> > > SHUTDOWN_CHECKPOINT) or if there are invalid slots then the upgrade
> > > won't proceed and we will request user to remove such slots or ensure
> > > that WAL is consumed by slots. So, I think in the case you mentioned,
> > > the upgrade won't succeed.
> >
> > What if new slots are added while the old instance is started in the middle of
> > pg_upgrade, *after* the various checks are done?
> >
>
> They won't be copied but I think that won't be any different than
> other objects like tables. Anyway, I have another idea which is to not
> allow creating slots during binary upgrade unless one specifically
> requests it by having an API like binary_upgrade_allow_slot_create()
> similar to existing APIs binary_upgrade_*.
>

Sawada-San, Julien, and others, do you have any thoughts on the above point?

-- 
With Regards,
Amit Kapila.

Commits

  1. Fix issues in binary_upgrade_logical_slot_has_caught_up().

  2. Fix a random failure in 003_logical_slots.pl.

  3. Fix a test in 003_logical_slots.

  4. Fix uninitialized slot array access during the upgrade.

  5. Fix the test 003_logical_slots.

  6. Commit b195e6d482 forgot to update meson.build.

  7. Use shorter file names in the upgrade logical slots test.

  8. Migrate logical slots to the new node during an upgrade.

  9. Flush logical slots to disk during a shutdown checkpoint if required.

  10. Prevent possibility of panics during shutdown checkpoint.