28b0478755
Clauses in the lists retained by postgres_fdw during planning were sometimes bare boolean clauses, sometimes RestrictInfos, and sometimes a mixture of the two in the same list. The comment about that situation didn't come close to telling the full truth, either. Aside from being confusing, this had a couple of bad practical consequences: * waste of planning cycles due to inability to cache per-clause selectivity and cost estimates; * sometimes, RestrictInfos would sneak into the fdw_private list of a finished Plan node, causing failures if, for example, we tried to ship the Plan tree to a parallel worker. (It may well be that it's a bug in the parallel-query logic that we would ever try to ship such a plan to a parallel worker, but in any case this deserves to be cleaned up.) To fix, rearrange so that clause lists in PgFdwRelationInfo are always lists of RestrictInfos, and then strip the RestrictInfos at the last minute when making a Plan node. In passing do a bit of refactoring and comment cleanup in postgresGetForeignPlan and foreign_join_ok. Although the messiness here dates back at least to 9.6, there's no evidence that it causes anything worse than wasted planning cycles in 9.6, so no back-patch for now. Per fuzz testing by Andreas Seltenreich. Tom Lane and Ashutosh Bapat Discussion: https://postgr.es/m/87tw5x4vcu.fsf@credativ.de
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: http://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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.