[ reposting some questions asked in the wrong thread ] What I'd like to understand about this patch is how it relates to Amit L.'s work on making the planner faster for partitioned UPDATE/DELETE cases (https://commitfest.postgresql.org/22/1778/). I think that that might render this moot? Amit's already getting rid of unnecessary partition locking.
In any case, I'd counsel against putting planner outputs into RangeTblEntry. Someday we ought to make parse trees read-only to the planner, as plan trees are to the executor; defining them to carry planner results kneecaps any such effort before it starts. Not to mention the unpleasant consequences for the footprint of this patch. regards, tom lane