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Remove RestrictInfo.nullable_relids, along with a good deal of infrastructure that calculated it. One use-case for it was in join_clause_is_movable_to, but we can now replace that usage with a check to see if the clause's relids include any outer join that can null the target relation. The other use-case was in join_clause_is_movable_into, but that test can just be dropped entirely now that the clause's relids include outer joins. Furthermore, join_clause_is_movable_into should now be accurate enough that it will accept anything returned by generate_join_implied_equalities, so we can restore the Assert that was diked out in commit 95f4e59c3. Remove the outerjoin_delayed mechanism. We needed this before to prevent quals from getting evaluated below outer joins that should null some of their vars. Now that we consider varnullingrels while placing quals, that's taken care of automatically, so throw the whole thing away. Teach remove_useless_result_rtes to also remove useless FromExprs. Having done that, the delay_upper_joins flag serves no purpose any more and we can remove it, largely reverting 11086f2f2. Use constant TRUE for "dummy" clauses when throwing back outer joins. This improves on a hack I introduced in commit 6a6522529. If we have a left-join clause l.x = r.y, and a WHERE clause l.x = constant, we generate r.y = constant and then don't really have a need for the join clause. But we must throw the join clause back anyway after marking it redundant, so that the join search heuristics won't think this is a clauseless join and avoid it. That was a kluge introduced under time pressure, and after looking at it I thought of a better way: let's just introduce constant-TRUE "join clauses" instead, and get rid of them at the end. This improves the generated plans for such cases by not having to test a redundant join clause. We can also get rid of the ugly hack used to mark such clauses as redundant for selectivity estimation. Patch by me; thanks to Richard Guo for review. Discussion: https://postgr.es/m/830269.1656693747@sss.pgh.pa.us
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.