On Wed, Jun 19, 2024 at 12:49 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Richard Guo <guofengli...@gmail.com> writes: > > It seems to me that the new operator is somewhat artificial, since it is > > designed to support a mergejoin but lacks a valid commutator. So before > > we proceed to discuss the fix, I'd like to know whether this is a valid > > issue that needs fixing.
> I do not think we should add a great deal of complexity or extra > planner cycles to deal with this; but if it can be fixed at low > cost, we should. I think we can simply verify the validity of commutators for clauses in the form "inner op outer" when selecting mergejoin/hash clauses. If a clause lacks a commutator, we should consider it unusable for the given pair of outer and inner rels. Please see the attached patch. Thanks Richard
v2-0001-Check-the-validity-of-commutators-for-merge-hash-clauses.patch
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