On Fri, Sep 5, 2025 at 11:45 AM Andrei Lepikhov <[email protected]> wrote: > > On 1/9/2025 22:26, Alexander Korotkov wrote: > > On Thu, Jul 31, 2025 at 5:20 PM Andrei Lepikhov <[email protected]> wrote: > >> See this minor correction in the attachment. postgres_fdw tests are > >> stable now. > > > > I have another idea. What if we allow MergeAppend paths only when at > > least one subpath is preordered. This trick also allow us to exclude > > MergeAppend(Sort) dominating Sort(Append). I see the regression tests > > changes now have much less volume and looks more reasonable. What do > > you think? > I believe a slight mistake has been made with the total_has_ordered / > startup_has_ordered parameters, which has caused unnecessary test > changes in inherit.out (See updated patch in the attachment). Although > not the best test in general (it depends on the autovacuum), it > highlighted the case where a startup-optimal strategy is necessary, even > when a fractional-optimal path is available, which may lead to continue > of the discussion [1].> > > Also, do you think get_cheapest_fractional_path_for_pathkeys_ext() and > > get_cheapest_path_for_pathkeys_ext() should consider incremental sort? > > The revised patch teaches them to do so. > Following 55a780e9476 [2] it should be considered, of course.
Great, thank you for catching this. The diff of costs is attached. I see the costs now are better or within the fuzz factor. ------ Regards, Alexander Korotkov Supabase
costs.diff
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