On Mon, Jul 27, 2020 at 12:52 PM Alvaro Herrera <alvhe...@2ndquadrant.com> wrote: > On 2020-Jul-27, Peter Geoghegan wrote: > > The v4-0001-Remove-hashagg_avoid_disk_plan-GUC.patch changes are > > surprisingly complicated. It would be nice if you could take a look at > > that aspect (or confirm that it's included in your review). > > I think you mean "it replaces surprisingly complicated code with > straightforward code". Right? Because in the previous code, there was > a lot of effort going into deciding whether the path needed to be > generated; the new code just generates the path always.
Yes, that's what I meant. It's a bit tricky. For example, I have removed a redundant "cheapest_total_path != NULL" test in create_partial_grouping_paths() (two, actually). But these two tests were always redundant. I have to wonder if I missed the point. Though it seems likely that that was just an accident. Accretions of code over time made the code work like that; nothing more. -- Peter Geoghegan