Re: Remove Deprecated Exclusive Backup Mode

On Wed, 2018-12-12 at 13:31 +0900, Robert Haas wrote:
> On Wed, Dec 12, 2018 at 1:23 PM David Steele <david@pgmasters.net> wrote:
> > I didn't get the impression that Peter was against, he just thought that
> > it needed to stand on its own, rather than be justified by the
> > recovery.conf changes, which I agree with.
> > 
> > Simon rather clearly said that he thinks we should wait until the next
> > release, which I don't see as being entirely against.
> 
> Well, nobody is saying that we should NEVER remove this.  The
> discussion is about what to do in v12.
> 
> Most of the features I've been involved in removing have been
> deprecated for 5+ years.  The first release where this one was
> deprecated was only 2 years ago.  So it feels dramatically faster to
> me than what I think we have typically done.
> 
> Actually, I hadn't realized until this discussion that the exclusive
> backup interface was actually deprecated -- I thought we were just
> recommending the new non-exclusive backup interface should be used.
> If we're in a rush to remove this (and apparently many of us are), I
> think we should make that warning a lot more prominent, maybe copy it
> into a few more places, and back-patch the changes.

+1

I too only learned about this recently, while the problem with exclusive
backups has been known at least since 2008 (c979a1fe), and nobody felt
this to be a terrible problem back then.

I believe that the danger is greatly overrated.  It is not like you end
up with a corrupted database after a crash, and you get a pretty helpful
error message.  Many people are happy enough to live with that.

I'm on board with deprecating and removing it eventually, but I see no
problem in waiting for the customary 5 years.
And yes, a prominent warning in the next major release notes would be
a good thing.

Yours,
Laurenz Albe