upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-03-07 15:50:44 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions
Base de données relationnelle
59635 commits 38 branches 679 tags 867 MiB
C 84.7%
PLpgSQL 6.1%
Perl 4.8%
Yacc 1.2%
Meson 0.7%
Other 2.4%
Find a file
Michael Paquier dcdc95cb4d Ignore temporary relations in RelidByRelfilenumber() 
Temporary relations may share the same RelFileNumber with a permanent
relation, or other temporary relations associated with other sessions.

Being able to uniquely identify a temporary relation would require
RelidByRelfilenumber() to know about the proc number of the temporary
relation it wants to identify, something it is not designed for since
its introduction in f01d1ae3a1.

There are currently three callers of RelidByRelfilenumber():
- autoprewarm.
- Logical decoding, reorder buffer.
- pg_filenode_relation(), that attempts to find a relation OID based on
a tablespace OID and a RelFileNumber.

This makes the situation problematic particularly for the first two
cases, leading to the possibility of random ERRORs due to
inconsistencies that temporary relations can create in the cache
maintained by RelidByRelfilenumber().  The third case should be less of
an issue, as I suspect that there are few direct callers of
pg_filenode_relation().

The window where the ERRORs are happen is very narrow, requiring an OID
wraparound to create a lookup conflict in RelidByRelfilenumber() with a
temporary table reusing the same OID as another relation already cached.
The problem is easier to reach in workloads with a high OID consumption
rate, especially with a higher number of temporary relations created.

We could get pg_filenode_relation() and RelidByRelfilenumber() to work
with temporary relations if provided the means to identify them with an
optional proc number given in input, but the years have also shown that
we do not have a use case for it, yet.  Note that this could not be
backpatched if pg_filenode_relation() needs changes.  It is simpler to
ignore temporary relations.

Reported-by: Shenhao Wang <wangsh.fnst@fujitsu.com>
Author: Vignesh C <vignesh21@gmail.com>
Reviewed-By: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Takamichi Osumi <osumi.takamichi@fujitsu.com>
Reviewed-By: Michael Paquier <michael@paquier.xyz>
Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com>
Reported-By: Shenhao Wang <wangsh.fnst@fujitsu.com>
Discussion: https://postgr.es/m/bbaaf9f9-ebb2-645f-54bb-34d6efc7ac42@fujitsu.com
Backpatch-through: 13
2025-08-22 09:06:36 +09:00
config Don't put library-supplied -L/-I switches before user-supplied ones. 2025-07-29 15:17:41 -04:00
contrib Add CHECK_FOR_INTERRUPTS in contrib/pg_buffercache functions. 2025-08-19 12:11:37 -07:00
doc Ignore temporary relations in RelidByRelfilenumber() 2025-08-22 09:06:36 +09:00
src Ignore temporary relations in RelidByRelfilenumber() 2025-08-22 09:06:36 +09:00
.cirrus.star ci: Simplify ci-os-only handling 2025-08-14 12:02:42 -04:00
.cirrus.tasks.yml ci: Simplify ci-os-only handling 2025-08-14 12:02:42 -04:00
.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 commit 7229ebe011 to .git-blame-ignore-revs. 2024-09-14 20:17:30 +02:00
.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 Stamp 17.6. 2025-08-11 17:04:51 -04:00
configure.ac Stamp 17.6. 2025-08-11 17:04:51 -04:00
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_17_STABLE to its new status as a stable branch 2024-07-01 08:05:35 +09:00
meson.build Stamp 17.6. 2025-08-11 17:04:51 -04:00
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

README.md

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/.