704e393190
In final_cost_hashjoin(), commit 9c7f5229a allowed inner_unique cases to follow a code path previously used only for SEMI/ANTI joins; but it neglected to fix an if-test within that path that assumed SEMI and ANTI were the only possible cases. This resulted in a wrong value for hashjointuples, and an ensuing bad cost estimate, for inner_unique normal joins. Fortunately, for inner_unique normal joins we can assume the number of joined tuples is the same as for a SEMI join; so there's no need for more code, we just have to invert the test to check for ANTI not SEMI. It turns out that in two contrib tests in which commit 9c7f5229a changed the plan expected for a query, the change was actually wrong and induced by this estimation error, not by any real improvement. Hence this patch also reverts those changes. Per report from RK Korlapati. Backpatch to v10 where the error was introduced. David Rowley Discussion: https://postgr.es/m/CA+SNy03bhq0fodsfOkeWDCreNjJVjsdHwUsb7AG=jpe0PtZc_g@mail.gmail.com
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