Re: [HACKERS] move collation import to backend

Jeff Janes <jeff.janes@gmail.com> writes:
> With this commit, I'm getting 'make check' fail at initdb with the error:

> 2017-01-18 07:47:50.565 PST [43691] FATAL:  collation "aa_ER@saaho" for
> encoding "UTF8" already exists

Yeah, so are large chunks of the buildfarm.  Having now read the patch,
I see that the problem is that it simply ignored the de-duplication
logic that existed in initdb's implementation.  That was put there
on the basis of bitter experience, as I recall.

The new code seems to think it's sufficient to do an "if not exists"
insertion when generating abbreviated names, but that's wrong, and
even if it avoided outright failures, it would be nondeterministic
(I doubt "locale -a" is guaranteed to emit locale names in any
particular order).

I think this needs to be reverted pending redesign of the de-duplication
coding.
        regards, tom lane