Re: First draft of the PG 15 release notes

2022年5月12日(木) 11:01 Bruce Momjian <bruce(at)momjian(dot)us>:
>
> On Thu, May 12, 2022 at 10:37:56AM +0900, Ian Lawrence Barwick wrote:
> > >> Remove exclusive backup mode (David Steele, Nathan Bossart)
> > >>
> > >> If the database server stops abruptly while in this mode, the server could fail to start.
> > >> The non-exclusive backup mode requires a continuous database connection during the backup.
> >
> > It'd be useful to mention exclusive backup mode has been deprecated since 9.6,
> > lest the impression arise that an important-sounding feature has been torn out
> > suddenly.
>
> Well, the documentation was clear about it being deprecated, so I don't
> see a need to mention it in the release notes.

Looking at the release notes from the point of view of someone who has maybe
not been following the long-running debate on removing exclusive backups:

"Important-sounding backup thing is suddenly gone! What was that
again? Hmm, can't
find anything in the now-current Pg 15 docs [*], do I need to worry
about this!?"

[*] the backup section has removed all mention of the word "exclusive"
https://www.postgresql.org/docs/devel/continuous-archiving.html#BACKUP-LOWLEVEL-BASE-BACKUP

versus:

"Long-deprecated thing is finally gone, ah OK whatever".

I am thinking back here to a point in my working life where the
release notes were reviewed
(by a team including non-Pg specialists) for potential issues when
considering a major
upgrade - from experience the more clarity with this kind of change
the better so
as not to unnecessarily raise alarm bells.

> > Also not sure why we need to mention that non-exclusive backup
> > requires a continuous database connection, AFAIR that was also the case with
> > exclusive backups.
>
> Uh, you could do pg_backup_start, disconnect, then pg_backup_stop, no?
> I thought the non-exclusive mode required a continuous connection
> because it aborts if you disconnect.

Aha, you are right, I was conflating server shutdown with disconnection.

> > The patch also removed 4 and added 2 new functions, a change which anyone
> > maintaining backup utilities would need to be aware of.
> >
> > Patch attached with suggested changes.
>
> Oh, good points, I had not noticed those renames and removals. URL
> updated with new text.

Thanks!

Regards

Ian Barwick

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