054ff3b33a
a316a3bc fixed the code in build_simpl_rel() that propagates RelOptInfo.userid from parent to child rels so that it works correctly for the child rels of a UNION ALL subquery rel, though no tests were added in that commit. So do so here. As noted in the discussion, coming up with a test case in the core regression suite for this fix has turned out to be tricky, so the test case is added to the postgres_fdw's suite instead. postgresGetForeignRelSize()'s use of user mapping for the user specified in RelOptInfo.userid makes it relatively easier to craft a test case around. Discussion: https://postgr.es/m/CA%2BHiwqH91GaFNXcXbLAM9L%3DzBwUmSyv699Mtv3i1_xtk9Xec_A%40mail.gmail.com Backpatch-through: 16
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/.