Re: CREATE COLLATION does not sanitize ICU's BCP 47 language tags. Should it?

On Mon, Sep 25, 2017 at 12:52 PM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> That must have been the real reason why you canonicalized
> pg_collation.collname (I doubt it had anything to do with how keyword
> variants used to be created during initdb, as you suggested). As Tom
> pointed out recently, we've actually always canonicalized collation
> name for libc.

On further examination, none of this really matters, because you
simply cannot store ICU locale names like "en_US" within pg_collation;
it's impossible to do that without breaking many things that have
worked for a long time. initdb already canonicalizes the available
libc collations to produce collations whose names have exactly the
same "en_US" format. There will typically be both "en_US" and
"en_US.utf8" entries within pg_collation with Glibc on Linux, for example
(the former is created a convenient alias for the latter when the
database encoding is UTF-8).

--
Peter Geoghegan