Klaudie Willis <Klaudie.Willis@xxxxxxxxxxxxxx> writes: > I'd like to add, that when I do the same query DIRECTLY on the bigtable_y2020 (instead of the partition parent) it does change to "index scan" again. Yeah. I think the issue here is that add_paths_to_append_rel only considers cheapest-total paths for the member relations. Seeing that it's already considering a slightly ridiculous number of parallelization options, I'm hesitant to throw in cheapest-startup considerations as well, for fear of blowing out planning time. Maybe the right way to improve this is to bypass add_paths_to_append_rel entirely when there's exactly one surviving child rel, and make it just use all the surviving paths for that child. regards, tom lane
