739f1d6218
It's possible, in admittedly-rather-contrived cases, for an eclass to generate a derived "join" qual that constrains the post-outer-join value(s) of some RHS variable(s) without mentioning the LHS at all. While the mechanisms were set up to work for this, we fell foul of the "get_common_eclass_indexes" filter installed by commit 3373c7155: it could decide that such an eclass wasn't relevant to the join, so that the required qual clause wouldn't get emitted there or anywhere else. To fix, apply get_common_eclass_indexes only at inner joins, where its rule is still valid. At an outer join, fall back to examining all eclasses that mention either input (or the OJ relid, though it should be impossible for an eclass to mention that without mentioning either input). Perhaps we can improve on that later, but the cost/benefit of adding more complexity to skip some irrelevant eclasses is dubious. To allow cheaply distinguishing outer from inner joins, pass the ojrelid to generate_join_implied_equalities as a separate argument. This also allows cleaning up some sloppiness that had crept into the definition of its join_relids argument, and it allows accurate calculation of nominal_join_relids for a child outer join. (The latter oversight seems not to have been a live bug, but it certainly could have caused problems in future.) Also fix what might be a live bug in check_index_predicates: it was being sloppy about what it passed to generate_join_implied_equalities. Per report from Richard Guo. Discussion: https://postgr.es/m/CAMbWs4-DsTBfOvXuw64GdFss2=M5cwtEhY=0DCS7t2gT7P6hSA@mail.gmail.com
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/.