Re: pg_collation.collversion for C.UTF-8

On Mon, 2023-06-05 at 19:43 +0200, Daniel Verite wrote:
> But in the meantime, personally I don't quite see why Postgres should
> start forcing C.UTF-8 to sort differently in the database than in the
> OS.

I can see both points of view. It could be surprising to users if
C.UTF-8 does not sort like C/memcmp, or surprising if it changes out
from under them. It could also be surprising that it wouldn't sort like
the current OS's libc interpretation of C.UTF-8.

What about ICU? How should provider=icu locale=C.UTF-8 behave? We
could:

a. Just pass it to the provider and see what happens (older versions of
ICU would interpret it as en-US-u-va-posix; newer versions would give
the root locale).

b. Consistently interpret it as en-US-u-va-posix.

c. Don't pass it to the provider at all and treat it with memcmp
semantics.

Regards,
    Jeff Davis