Re: Remove Deprecated Exclusive Backup Mode - Mailing list pgsql-hackers

Greetings,

* Robert Haas (robertmhaas@gmail.com) wrote:
> On Mon, Feb 25, 2019 at 11:23 AM Stephen Frost <sfrost@snowman.net> wrote:
> > If that argument did matter, we could go back and find the prior
> > discussions about the issues around the exclusive backup mode and about
> > removing it, or next year we could point to this thread about it, or the
> > year after, and say "well, we talked about it a lot, so now let's just
> > do it", but it all ends up looking the same to our users unless we
> > actually write into some kind of user-facing documentation or WARNINGs
> > or similar that something is going away.
>
> That's true.  But nobody's objecting to strengthening the warnings in
> the documentation.  People are objecting to removing the thing itself.

Then how long will we carry it forward?  How much warning do we need to
provide?

> > This isn't a fair argument either because we're having this *after* the
> > new API was implemented for backup- namely non-exclusive mode, which
> > *did* give people something better to use instead.
>
> There are several people who are saying that doesn't meet all their
> needs, giving reasons why it's problematic, and suggesting things that
> could be done to make it less problematic.  It's not OK to say "we can
> remove exclusive backup mode because now we have non-exclusive backup
> mode" unless other people actually agree that all the use cases are
> covered, and it appears that they don't.

I haven't heard anyone say it doesn't meet their needs, just that it's
not as easy to use, which is a fair critcism, but not the same thing.
I'm all for making the non-exclusive mode less problematic if we're able
to.  If that's something that would help us move forward with getting
rid of the exclusive backup mode than that's an area that I'd be willing
to put resources.

> > I disagree quite a bit with this statement- the existing documentation
> > is absolutely horrid and needs to be completely ripped out and rewritten
> > and maintaining the exclusive backup mode in such a rewrite would
> > absolutely be a *lot* of additional work.
> >
> > We actually took a shot at trying to improve the documentation while
> > continuing to cover both the exclusive and the non-exclusive mode and
> > it's hugely painful.
>
> Well, perhaps that's pain you need to incur.  The alternative seems to
> be to rip out something that people don't want ripped out.

... now I feel like I'm being told what to do.

The point is that keeping it actually *is* work, it isn't free, not even
in our tree.  Making our users stumble over the issues with it also
isn't free, that's another cost of keeping it.

> > I used to be one of those people.  I know that it looks fine and it
> > certainly seems appealing but having gone through bad experiences with
> > it, and seen others stumble through those same experiences time and time
> > again, I've learned that it really is an issue, and one that I would
> > very much like to avoid causing future users to stumble over.
>
> Sure, that sounds great.  But the way to do that is to continue
> improving the system until exclusive-mode backups really are not a
> useful thing any more, not to remove it while there are still a lot of
> people relying on it who can offer tangible explanations for their
> choice to do so.
>
> It feels to me like you are portraying the increasing number of people
> objecting to this change as naive or foolish or at least not as
> enlightened as you are, and I really object to that.  I happen to
> think that people like Christophe Pettus and Fujii Masao and Laurenz
> Albe are smart people whose opinions ought to be taken as just as
> valid as your own.

I honestly do doubt that they have had the same experiences that I have
had, but that doesn't mean that they're not smart or that I don't value
their opinion- I agree that they're all smart people and I certainly do
value their opinions.  That doesn't mean that I can't disagree with them
or can't explain why I disagree.

Thanks!

Stephen