Re: Eager aggregation, take 3

On Thu, Jun 26, 2025 at 11:01 AM Richard Guo <guofenglinux@gmail.com> wrote:
> Here is the patch based on the proposed ideas.  It includes the proof
> of correctness in the README and implements the strategy of pushing
> partial aggregation only to the lowest applicable join level where it
> is deemed useful.  This is done by introducing a "Relids apply_at"
> field to track that level and ensuring that partial aggregation is
> applied only at the recorded "apply_at" level.
>
> Additionally, this patch changes how grouped relations are stored.
> Since each grouped relation represents a partially aggregated version
> of a non-grouped relation, we now associate each grouped relation with
> the RelOptInfo of the corresponding non-grouped relation.  This
> eliminates the need for a dedicated list of all grouped relations and
> avoids list searches when retrieving a grouped relation.
>
> It also addresses other previously raised concerns, such as the
> potential memory blowout risks with large partial-aggregation values,
> and includes improvements to comments and the commit message.
>
> Another change is that this feature is now enabled by default.

This patch no longer applies; here's a rebased version.  Nothing
essential has changed.

Thanks
Richard