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

Dear Peter,

Thank you for giving explanation.

> 
> 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... */

I confirmed that current "XXX" comments must be removed by improving
or some decision. Therefore I kept current annotation.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED