Re: Remove Deprecated Exclusive Backup Mode

Greetings,

* Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
> On Wed, Jul 1, 2020 at 11:48 AM Magnus Hagander <magnus(at)hagander(dot)net> wrote:
> > We don't even need to make it an exclusive mode -- we can allow *nonexclusive* backups but remove the requirement to run start and stop backup in the same connection, which I believe is the problem that people have with the exclusive mode.
>
> Well, one of the big advantages of the non-exclusive mode is that the
> backup automatically is terminated if the connection is closed, which
> removes the possibility of leaving a backup in progress for a long
> time inadvertently. I think that back-tracking on that would probably
> be a step in the wrong direction.

What's the actual downside from having a forgotten backup being left
around for an extended period of time..?

> I agree with what I understand to be Bruce's position -- non-exclusive
> backup mode is better than exclusive mode backup mode, but exclusive
> backup mode is not broken and doesn't need to be removed. I think it's
> very sensible to continue to support exclusive backup mode but to
> encourage users to use non-exclusive backup mode instead. I find
> Stephen's position that exclusive backup mode cannot be used safely to
> be unsupported by any compelling evidence, and reviewing the thread, I
> find that there are a LOT of people who seem to agree.

I didn't realize there was a question regarding what happens if the DB
server ends up crashing during an exclusive backup. That hardly seems
to be safe if you care about having your database start up after a
crash, which seems like an important thing that we generally consider of
value considering the amount of effort we put into it.

I agree that there seems to be a number of people who want to ignore
that the system breaks down in that situation in order to keep exclusive
backup around, but, unlike the discussion being had between Magnus and
I, that doesn't actually move us forward at all in terms of providing a
good solution or being able to write the documentation in a sane way for
people who aren't PG hackers to be able to follow.

Thanks,

Stephen