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

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?

Or does anyone else feel this is a must-fix for v19?

David