David Rowley <david.rowley@2ndquadrant.com> writes:
> On 10 August 2015 at 07:50, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I've started to work on path-ification of the upper planner (finally),
> I was digging around the grouping_planner() last week with the intentions
> of making some changes there to allow GROUP BY before join, but in the end
> decided to stay well clear of this area until this pathification is done.
> So far I've managed to keep my changes away from the upper planner and I've
> added "GroupingPath" types, which from what I can predict of what you'll be
> making changes to, I think you'll also need to have grouping_planner()
> return a few variations of "GroupingPath" to allow the paths list to be
> passed up to subquery_planner() and on up to functions
> like recurse_set_operations() so that they have the option of choosing
> GroupAggregate / MergeAppend to implement UNION.
> If I'm right on this, then maybe there's a few things you can copy and
> paste from the patch I posted here:
> http://www.postgresql.org/message-id/CAKJS1f-sEcm=gTfS-DqjsOcsZ-vLhrP_hSRNtJjq-S7Egn8Rqw@mail.gmail.com
> specifically around create_grouping_path()?
Yeah, I saw your patch, but have not yet had time to think about what
parts of it I could borrow.
regards, tom lane
