Horton

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

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Julien Rouhaud <rjuju123@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2023-04-11T08:20:43Z
Lists: pgsql-hackers 
On Sat, Apr 8, 2023 at 12:00 AM Hayato Kuroda (Fujitsu)
<kuroda.hayato@fujitsu.com> wrote:
>
...
> > 17. main
> >
> > + /*
> > + * Create replication slots if requested.
> > + *
> > + * XXX This must be done after doing pg_resetwal command because the
> > + * command will remove required WALs.
> > + */
> > + if (user_opts.include_slots)
> > + {
> > + start_postmaster(&new_cluster, true);
> > + create_replicaiton_slots();
> > + stop_postmaster(false);
> > + }
> > +
> >
> > I don't think that warrants a "XXX" style comment. It is just a "Note:".
>
> Fixed. Could you please tell me the classification of them if you can?

Hopefully, someone will correct me if this explanation is wrong, but
my understanding of the different prefixes is like this --

"XXX" is used as a marker for future developers to consider maybe
revisiting/improving something that the comment refers to
e.g.
/* XXX - it would be better to code this using blah but for now we did
not.... */
/* XXX - option 'foo' is not currently supported but... */
/* XXX - it might be worth considering adding more checks or an assert
here because... */

OTOH, "Note" is just for highlighting why something is the way it is,
but with no implication that it should be revisited/changed in the
future.
e.g.
/* Note: We deliberately do not test the state here because... */
/* Note: This memory must be zeroed because... */
/* Note: This string has no '\0' terminator so... */

------
Kind Regards,
Peter Smith.
Fujitsu Australia

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.