Re: Removal of deprecated views pg_user, pg_group, pg_shadow

Robert,

* Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
> On Mon, Feb 13, 2017 at 2:42 PM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
> > Well, we can remove them from PG10 and pgAdmin3 (and others) be adjusted
> > to use the new ones, conditionally on server version. Surely pgAdmin3
> > is going to receive further updates, given that it's still widely used?
>
> According to the pgAdmin web site, no. (Yeah, that does seem odd.)

I really do not think the PG core project should be held hostage by an
external and apparently not-really-maintained project. What if we
introduce some other difference in PG10 that breaks pgAdmin3? Are we
going to roll that change back? Are we sure that none exists already?

And, as I understand it, pgAdmin3 hasn't got support for features
introduced as far back as 9.5 either, surely it's not going to have
support added to it for the publication/subscription things or
declarative partitioning, should we rip those out to accomedate
pgAdmin3?

> >> IMHO, these views aren't costing us much. It'd be nice to get rid of
> >> them eventually but a view definition doesn't really need much
> >> maintenance.
> >
> > Maybe not, but the fact that they convey misleading information is bad.
>
> Has anyone actually been confused by them?

This isn't something we can prove. Nor can we prove that no one has
ever been confused. What we can show is that they're clearly misleading
and inconsistent. Even if no one is ever confused by them, having them
is bad.

> I'm a bit skeptical about the idea that these are misleading people,
> because the information is no more or less misleading now than it was
> in PostgreSQL 8.1 when the views were introduced. And evidently it
> was not so misleading at that time as to make us thing that a hard
> compatibility break was warranted.

No, that's not how I recall the discussion going down when I introduced
them in 8.1. It was more along the lines of "Here's a patch, oh, and I
added these views too." The archives might prove me wrong, as memory
does fade after years, but I certainly don't recall any lengthy
discussion about if we should add these views or not. In short, my
recollection is that we added them because it was easy to do at the time
and we didn't have the foresight to realize just how hard they would
become to get rid of and how much time they would suck up from people
arguing about them.

This is part of the bigger picture that we need to consider whenever we
think about backwards-compat mis-features.

> On the other hand, I suppose that the last version of pgAdmin 3 isn't
> likely to work with future major versions of PostgreSQL anyway unless
> somebody updates it, and if somebody decides to update it for the
> other changes in v10 then updating it for the removal of these views
> won't be much extra work. So maybe it doesn't matter.

Indeed.

Thanks!

Stephen