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Tom Lane 12bc329177 Don't allow CTEs to determine semantic levels of aggregates.
The fix for bug #19055 (commit b0cc0a71e) allowed CTE references in
sub-selects within aggregate functions to affect the semantic levels
assigned to such aggregates.  It turns out this broke some related
cases, leading to assertion failures or strange planner errors such
as "unexpected outer reference in CTE query".  After experimenting
with some alternative rules for assigning the semantic level in
such cases, we've come to the conclusion that changing the level
is more likely to break things than be helpful.

Therefore, this patch undoes what b0cc0a71e changed, and instead
installs logic to throw an error if there is any reference to a
CTE that's below the semantic level that standard SQL rules would
assign to the aggregate based on its contained Var and Aggref nodes.
(The SQL standard disallows sub-selects within aggregate functions,
so it can't reach the troublesome case and hence has no rule for
what to do.)

Perhaps someone will come along with a legitimate query that this
logic rejects, and if so probably the example will help us craft
a level-adjustment rule that works better than what b0cc0a71e did.
I'm not holding my breath for that though, because the previous
logic had been there for a very long time before bug #19055 without
complaints, and that bug report sure looks to have originated from
fuzzing not from real usage.

Like b0cc0a71e, back-patch to all supported branches, though
sadly that no longer includes v13.

Bug: #19106
Reported-by: Kamil Monicz <kamil@monicz.dev>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/19106-9dd3668a0734cd72@postgresql.org
Backpatch-through: 14
2025-11-18 12:56:55 -05:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Don't put library-supplied -L/-I switches before user-supplied ones. 2025-07-29 15:17:40 -04:00
contrib postgres_fdw: Add more test coverage for EvalPlanQual testing. 2025-11-06 12:15:01 +09:00
doc doc: clarify that pg_upgrade preserves "optimizer" stats. 2025-11-17 18:55:41 -05:00
src Don't allow CTEs to determine semantic levels of aggregates. 2025-11-18 12:56:55 -05:00
.abi-compliance-history Update .abi-compliance-history for change to CreateStatistics(). 2025-11-17 14:14:41 -06:00
.cirrus.star ci: Simplify ci-os-only handling 2025-08-14 12:09:53 -04:00
.cirrus.tasks.yml ci: Improve OpenBSD core dump backtrace handling. 2025-11-06 17:49:22 +13:00
.cirrus.yml ci: Per-repo configuration for manually trigger tasks 2025-08-14 11:33:44 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add script to keep .editorconfig in sync with .gitattributes 2025-02-01 10:09:45 +01:00
.git-blame-ignore-revs Add previous commit to .git-blame-ignore-revs. 2025-10-21 10:02:19 -05:00
.gitattributes Fix git whitespace warning 2025-08-15 10:32:22 +02:00
.gitignore Update top-level .gitignore. 2022-12-04 15:23:00 -05:00
.mailmap Add a Git .mailmap file 2024-11-05 13:56:02 +01:00
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure Stamp 18.1. 2025-11-10 16:52:06 -05:00
configure.ac Stamp 18.1. 2025-11-10 16:52:06 -05:00
COPYRIGHT Align organization wording in copyright statement 2025-05-16 11:20:07 -04:00
GNUmakefile.in Allow selecting the git revision to be packaged by "make dist". 2024-05-03 11:08:50 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Adapt REL_18_STABLE to its new status as a stable branch 2025-06-29 23:00:00 -04:00
meson.build Add check for large files in meson.build 2025-11-12 09:02:29 +09:00
meson_options.txt Add support for basic NUMA awareness 2025-04-07 23:08:17 +02:00
README.md Adapt REL_18_STABLE to its new status as a stable branch 2025-06-29 23:00:00 -04:00

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/18/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/18/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/.