On Mon, Nov 6, 2017 at 11:20 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > On Mon, Nov 6, 2017 at 3:51 AM, Robert Haas <robertmh...@gmail.com> wrote: >> This looks like it's on the right track to me. I hope Tom will look >> into it, but if he doesn't I may try to get it committed myself. >> >> - if (rel->reloptkind == RELOPT_BASEREL) >> - generate_gather_paths(root, rel); >> + if (rel->reloptkind == RELOPT_BASEREL && >> + root->simple_rel_array_size > 2 && >> + !root->append_rel_list) >> >> This test doesn't look correct to me. Actually, it doesn't look >> anywhere close to correct to me. So, one of us is very confused... >> not sure whether it's you or me. >> > It is quite possible that I haven't got it right, but it shouldn't be > completely bogus as it stands the regression tests and some manual > verification. Can you explain what is your concern about this test?
Well, I suppose that test will fire for a baserel when the total number of baserels is at least 3 and there's no inheritance involved. But if there are 2 baserels, we're still not the topmost scan/join target. Also, even if inheritance is used, we might still be the topmost scan/join target. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers