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Tom Lane 36fb9ef269 Detect whether plpgsql assignment targets are "local" variables.
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
2025-02-11 12:27:15 -05:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Remove flex version checks 2025-01-17 09:30:42 +01:00
contrib Virtual generated columns 2025-02-07 09:46:59 +01:00
doc docs: EUC_TW can be up to four bytes wide, not three 2025-02-10 10:03:37 -05:00
src Detect whether plpgsql assignment targets are "local" variables. 2025-02-11 12:27:15 -05:00
.cirrus.star Remove duplicate words in docs and code comments. 2023-10-09 09:18:47 +05:30
.cirrus.tasks.yml meson: ci: ensure tests are built before running them 2025-02-04 17:56:19 -05:00
.cirrus.yml ci: Make compute resources for CI configurable 2023-08-23 15:15:28 -07:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
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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/.