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Melanie Plageman cc6be07ebd Increase default maintenance_io_concurrency to 16
Since its introduction in fc34b0d9de, the default
maintenance_io_concurrency has been larger than the default
effective_io_concurrency. maintenance_io_concurrency primarily
controlled prefetching done on behalf of the whole system, for
operations like recovery. Therefore it makes sense for it to have a
value equal to or greater than effective_io_concurrency, which controls
I/O concurrency for reading a relation in a bitmap heap scan.

ff79b5b2ab increased effective_io_concurrency to 16, so we'll increase
maintenance_io_concurrency as well. For now, though, we'll keep the
defaults of effective_io_concurrency and maintenance_io_concurrency
equal to one another (16).

On fast, high IOPs systems, significantly higher values of
maintenance_io_concurrency are observably beneficial [1]. However, such
values would flood low IOPs systems and increase overall system I/O
latency.

It is worth mentioning that since 9256822608 and c3e775e608,
maintenance_io_concurrency also controls the I/O concurrency of each
vacuum worker. Since many autovacuum workers may be simultaneously
issuing I/Os, we want to keep maintenance_io_concurrency appropriately
conservative.

[1] https://postgr.es/m/c5d52837-6256-0556-ac8c-d6d3d558820a%40enterprisedb.com

Suggested-by: Jakub Wartak <jakub.wartak@enterprisedb.com>
Discussion: https://postgr.es/m/CAKZiRmxdHQaU%2B2Zpe6d%3Dx%3D0vigJ1sfWwwVYLJAf%3Dud_wQ_VcUw%40mail.gmail.com
2025-03-18 09:08:10 -04:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
contrib Make it possible for loadable modules to add EXPLAIN options. 2025-03-18 08:41:12 -04:00
doc Increase default maintenance_io_concurrency to 16 2025-03-18 09:08:10 -04:00
src Increase default maintenance_io_concurrency to 16 2025-03-18 09:08:10 -04:00
.cirrus.star Remove duplicate words in docs and code comments. 2023-10-09 09:18:47 +05:30
.cirrus.tasks.yml ci: Remove installation of libcurl 2025-03-05 22:12:20 +01:00
.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 203c1b4cc4 to .git-blame-ignore-revs. 2025-03-17 15:58:02 -05:00
.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 Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
configure.ac Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
COPYRIGHT Update copyright for 2025 2025-01-01 11:21:55 -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 Remove AIX support 2024-02-28 15:17:23 +04:00
meson_options.txt Add support for OAUTHBEARER SASL mechanism 2025-02-20 16:25:17 +01:00
meson.build Make test portlock logic work with meson 2025-02-21 11:25:05 -05:00
README.md Revise the style of a paragraph in README.md. 2024-03-21 10:16:41 -05:00

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/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/.