Re: Partial aggregates pushdown

Hi.

Tomas Vondra писал 2021-10-15 17:56:
> As for the proposed approach, it's probably good enough for the first
> version to restrict this to aggregates where the aggregate result is
> sufficient, i.e. we don't need any new export/import procedures.
>
> But it's very unlikely we'd want to restrict it the way the patch does
> it, i.e. based on aggregate name. That's both fragile (people can
> create new aggregates with such name) and against the PostgreSQL
> extensibility (people may implement custom aggregates, but won't be
> able to benefit from this just because of name).
>
> So for v0 maybe, but I think there neeeds to be a way to relax this in
> some way, for example we could add a new flag to pg_aggregate to mark
> aggregates supporting this.
>

Updated patch to mark aggregates as pushdown-safe in pg_aggregates.

So far have no solution for aggregates with internal aggtranstype.
--
Best regards,
Alexander Pyhalov,
Postgres Professional