On Tue, Jun 4, 2024 at 6:51 PM Tender Wang <tndrw...@gmail.com> wrote: > Yeah, Richard commented the v1 patch about JOIN_UNIQUE_INNER in [1] > > * I think we should not consider materializing the cheapest inner path > if we're doing JOIN_UNIQUE_INNER, because in this case we have to > unique-ify the inner path. > > We don't consider material inner path if jointype is JOIN_UNIQUE_INNER in > match_unsorted_order(). > So here is as same logic as match_unsorted_order(). I added comments to > explain why.
I looked through the v4 patch and found an issue. For the plan diff: + -> Nested Loop + -> Parallel Seq Scan on prt1_p1 t1_1 + -> Materialize + -> Sample Scan on prt1_p1 t2_1 + Sampling: system (t1_1.a) REPEATABLE (t1_1.b) + Filter: (t1_1.a = a) This does not seem correct to me. The inner path is parameterized by the outer rel, in which case it does not make sense to add a Materialize node on top of it. I updated the patch to include a check in consider_parallel_nestloop ensuring that inner_cheapest_total is not parameterized by outerrel before materializing it. I also tweaked the comments, test cases and commit message. Thanks Richard
v5-0001-Consider-materializing-the-cheapest-inner-path-in-parallel-nestloop.patch
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