Re: [18] Policy on IMMUTABLE functions and Unicode updates

On 7/23/24 15:26, Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> Also, Noah has pointed out that C.UTF-8 introduces some
>> forward-compatibility hazards of its own, at least with respect to
>> ctype semantics. I don't have a clear view of what ought to be done
>> about that, but if we just replace a dependency on an unstable set of
>> libc definitions with a dependency on an equally unstable set of
>> PostgreSQL definitions, we're not really winning.
>
> No, I think we *are* winning, because the updates are not "equally
> unstable": with pg_c_utf8, we control when changes happen. We can
> align them with major releases and release-note the differences.
> With libc-based collations, we have zero control and not much
> notification.

+1

>> Do we need to version the new ctype provider?
>
> It would be a version for the underlying Unicode definitions,
> not the provider as such, but perhaps yes. I don't know to what
> extent doing so would satisfy Noah's concern; but if it would do
> so I'd be happy with that answer.

I came to the same conclusion. I think someone mentioned somewhere on
this thread that other databases support multiple Unicode versions. I
think we need to figure out how to do that too.

--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com