90e0f9fd8c
The original coding (from c33869cc3) failed with "more than one row returned by a subquery used as an expression" if there were unrelated triggers of the same tgname on parent partitioned tables. (That's possible because statement-level triggers don't get inherited.) Fix by applying LIMIT 1 after sorting the candidates by inheritance level. Also, wrap the subquery in a CASE so that we don't have to execute it at all when the trigger is visibly non-inherited. Aside from saving some cycles, this avoids the need for a confusing and undocumented NULLIF(). While here, tweak the format of the emitted query to look a bit nicer for "psql -E", and add some explanation of this subquery, because it badly needs it. Report and patch by Justin Pryzby (with some editing by me). Back-patch to v13 where the faulty code came in. Discussion: https://postgr.es/m/20211217154356.GJ17618@telsasoft.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/.