36fb9ef269
Mark whether the target of a potentially optimizable assignment is "local", in the sense of being declared inside any exception block that could trap an error thrown from the assignment. (This implies that we needn't preserve the variable's value in case of an error. This patch doesn't do anything with the knowledge, but the next one will.) Normally, this requires a post-parsing scan of the function's parse tree, since we don't know while parsing a BEGIN ... construct whether we will find EXCEPTION at its end. However, if there are no BEGIN ... EXCEPTION blocks in the function at all, then all assignments are local, even those to variables representing function arguments. We optimize that common case by initializing the target_is_local flags to "true", and fixing them up with a post-scan only if we found EXCEPTION. Note that variables' default-value expressions are never interesting for expanded-variable optimization, since they couldn't contain a reference to the target variable anyway. But the code is set up to compute their target_param and target_is_local correctly anyway, for consistency and in case someone thinks of a use for that data. I added a bit of plpgsql_dumptree support to help verify that this code sets the flags as expected. I also added a plpgsql_dumptree call in plpgsql_compile_inline. It was at best an oversight that "#option dump" didn't work in a DO block; now it does. 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/.