Re: Allow a prosupport function to be attached to an aggregate

On 18/08/2026 06:56, David Rowley wrote:
> On Mon, 17 Aug 2026 at 18:13, Andrei Lepikhov <lepihov(at)gmail(dot)com> wrote:
>> Commit 42473b3b31 added SupportRequestSimplifyAggref, which the planner issues
>> for any Aggref whose function names a support function. Nice, but extensions
>> cannot reach it, because there is no way to attach a support function to an
>> aggregate:
>>
>> ALTER FUNCTION pg_catalog.sum(numeric) SUPPORT numeric_support;
>> ERROR: "pg_catalog.sum" is an aggregate function
>
> I failed to realise that there was no way to set that for user-defined
> aggregates. Not good. While I do agree that lack of extensibility is
> not aligned with the spirit of the project, my current thoughts are
> that now is a bit late to add this to v19.
>
> Is delaying this until v20 fine for you?
Yes, I can do it manually in pg_catalog for now - rewriting prosupport and
setting the dependency in the pg_depend. There’s no rush - it’s just about
keeping things tidy.

--
regards, Andrei Lepikhov,
pgEdge