c366d2bdba
Commit 1dc5ebc90 allowed PL/pgSQL to perform in-place updates of expanded-object variables that are being updated with assignments like "x := f(x, ...)". However this was allowed only for a hard-wired list of functions f(), since we need to be sure that f() will not modify the variable if it fails. It was always envisioned that we should make that extensible, but at the time we didn't have a good way to do so. Since then we've invented the idea of "support functions" to allow attaching specialized optimization knowledge to functions, and that is a perfect mechanism for doing this. Hence, adjust PL/pgSQL to use a support function request instead of hard-wired logic to decide if in-place update is safe. Preserve the previous optimizations by creating support functions for the three functions that were previously hard-wired. Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru> Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com> Discussion: https://postgr.es/m/CACxu=vJaKFNsYxooSnW1wEgsAO5u_v1XYBacfVJ14wgJV_PYeg@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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.