Andres Freund <and...@anarazel.de> writes: > On 2016-03-10 23:38:14 -0500, Tom Lane wrote: >> I'll do it ... just send me the list.
> After exporting make_agg, make_limit, make_sort_from_sortclauses and > making some trivial adjustments due to the pull_var_clause changes > change, Citus' tests pass on 9.6, bar some noise. OK, done. > Pathification made > some plans switch from hash-agg to sort-agg, and the other way round; > but that's obviously ok. I wonder whether that's pathification per se. Of the three core regression test EXPLAINs that changed in the pathification commit, two actually were a case of finding better plans. The other one was a random-looking swap between two plans with near-identical costs. When I looked into it, I found that the reason the planner liked the new plan better was that it was parallel-safe; add_path() saw the costs as fuzzily equal and allowed parallel-safe to be the determining factor in the choice. The old code hadn't done that because the hard-wired cost comparisons in grouping_planner() never took parallel-safety into account. But I'd call that a parallelism change, not a pathification change; it would certainly have appeared to be that if the patches had gone in in the opposite order. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers