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Jeff Davis 9dda30dd3d catcache.c: use C_COLLATION_OID for texteqfast/texthashfast.
The problem report was about setting GUCs in the startup packet for a
physical replication connection. Setting the GUC required an ACL
check, which performed a lookup on pg_parameter_acl.parname. The
catalog cache was hardwired to use DEFAULT_COLLATION_OID for
texteqfast() and texthashfast(), but the database default collation
was uninitialized because it's a physical walsender and never connects
to a database. In versions 18 and later, this resulted in a NULL
pointer dereference, while in version 17 it resulted in an ERROR.

As the comments stated, using DEFAULT_COLLATION_OID was arbitrary
anyway: if the collation actually mattered, it should have used the
column's actual collation. (In the catalog, some text columns are the
default collation and some are "C".)

Fix by using C_COLLATION_OID, which doesn't require any initialization
and is always available. When any deterministic collation will do,
it's best to consistently use the simplest and fastest one, so this is
a good idea anyway.

Another problem was raised in the thread, which this commit doesn't
fix (see second discussion link).

Reported-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/D18AD72A-5004-4EF8-AF80-10732AF677FA@yandex-team.ru
Discussion: https://postgr.es/m/4524ed61a015d3496fc008644dcb999bb31916a7.camel%40j-davis.com
Backpatch-through: 17
2026-04-22 10:23:54 -07:00
config Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code. 2026-02-25 11:57:26 -05:00
contrib Avoid memory leak on error while parsing pg_stat_statements dump file 2026-03-27 12:21:38 +02:00
doc doc: Correct context description for some JIT support GUCs 2026-04-21 08:45:13 +09:00
src catcache.c: use C_COLLATION_OID for texteqfast/texthashfast. 2026-04-22 10:23:54 -07:00
.abi-compliance-history Update .abi-compliance-history for change to enum ProcSignalReason 2026-04-16 23:48:41 +09:00
.cirrus.star ci: Simplify ci-os-only handling 2025-08-14 12:02:42 -04:00
.cirrus.tasks.yml Fix typo 2026-01-07 15:48:54 +01:00
.cirrus.yml ci: Per-repo configuration for manually trigger tasks 2025-08-14 11:33:47 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +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 10:32:07 +02:00
.gitignore Update top-level .gitignore. 2022-12-04 15:23:00 -05:00
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code. 2026-02-25 11:57:26 -05:00
configure.ac Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code. 2026-02-25 11:57:26 -05:00
COPYRIGHT Update copyright for 2026 2026-01-01 13:24:10 -05:00
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_17_STABLE to its new status as a stable branch 2024-07-01 08:05:35 +09:00
meson.build Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code. 2026-02-25 11:57:26 -05:00
meson_options.txt Allow selecting the git revision to be packaged by "make dist". 2024-05-03 11:08:50 -04:00
README.md Adapt REL_17_STABLE to its new status as a stable branch 2024-07-01 08:05:35 +09:00

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/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/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/.