upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-02-16 00:57:52 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions
Base de données relationnelle
61478 commits 38 branches 674 tags 837 MiB
C 84.9%
PLpgSQL 6.1%
Perl 4.7%
Yacc 1.2%
Meson 0.7%
Other 2.2%
Find a file
Peter Geoghegan e6eed40e44 Avoid BufferGetLSNAtomic() calls during nbtree scans. 
Delay calling BufferGetLSNAtomic() until we finish reading a page that
actually contains items that btgettuple will return to the executor.
This reduces the number of calls during plain index scans (we'll only
call BufferGetLSNAtomic() when _bt_readpage returns true), and totally
eliminates calls during index-only scans, bitmap index scans, and plain
index scans of an unlogged relation.

Currently, when checksums (or wal_log_hints) are enabled, acquiring a
page's LSN in BufferGetLSNAtomic() involves locking the buffer header
(which involves the use of spinlocks).  Testing has shown that enabling
page-level checksums causes large regressions with certain workloads,
especially on larger multi-socket systems.

The regression isn't tied to any Postgres 18 commit.  However, Postgres
18 commit 04bec894 made initdb use checksums by default, so it seems
prudent to address the problem now.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/941f0190-e3c6-4622-9ac7-c04e936e5fdb@vondra.me
Discussion: https://postgr.es/m/CAH2-Wzk-Dg5XWs_jDuiHt4_7ryrSY+n=vxmHY51EVqPDFsKXmg@mail.gmail.com
2025-06-06 10:19:44 -04:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config oauth: Move the builtin flow into a separate module 2025-05-01 09:14:30 -07:00
contrib pg_prewarm: Allow autoprewarm to use more than 1GB to dump blocks. 2025-06-06 08:18:27 -04:00
doc Doc: improve description of which role runs a trigger. 2025-06-05 15:24:15 -04:00
src Avoid BufferGetLSNAtomic() calls during nbtree scans. 2025-06-06 10:19:44 -04:00
.cirrus.star Remove duplicate words in docs and code comments. 2023-10-09 09:18:47 +05:30
.cirrus.tasks.yml ci: Check for missing dependencies in meson builds 2025-04-09 22:01:58 +02:00
.cirrus.yml ci: Test NetBSD and OpenBSD 2025-02-12 09:40:07 -05:00
.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 commit 4672b6223 to .git-blame-ignore-revs. 2025-06-01 14:58:42 -04:00
.gitattributes Add script to keep .editorconfig in sync with .gitattributes 2025-02-01 10:09:45 +01:00
.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 Make our usage of memset_s() conform strictly to the C11 standard. 2025-05-18 12:45:55 -04:00
configure.ac Make our usage of memset_s() conform strictly to the C11 standard. 2025-05-18 12:45:55 -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 Remove AIX support 2024-02-28 15:17:23 +04:00
meson.build Make our usage of memset_s() conform strictly to the C11 standard. 2025-05-18 12:45:55 -04:00
meson_options.txt Add support for basic NUMA awareness 2025-04-07 23:08:17 +02:00
README.md Revise the style of a paragraph in README.md. 2024-03-21 10:16:41 -05:00

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/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/.