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| author | Melanie Plageman <melanieplageman@gmail.com> | 2025-03-18 09:08:10 -0400 |
|---|---|---|
| committer | Melanie Plageman <melanieplageman@gmail.com> | 2025-03-18 09:08:10 -0400 |
| commit | cc6be07ebde2aef7cc0507f997f563ce77c00a00 (patch) | |
| tree | 8af20dffd2955c3d4f37527bba5ffbfbe252ae5a | |
| parent | 796bdda484c838313959f65e2b700f14ac7c0e66 (diff) | |
| download | postgresql-cc6be07ebde2aef7cc0507f997f563ce77c00a00.tar.gz postgresql-cc6be07ebde2aef7cc0507f997f563ce77c00a00.zip | |
Increase default maintenance_io_concurrency to 16
Since its introduction in fc34b0d9de27a, 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 9256822608f and c3e775e608f,
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
| -rw-r--r-- | doc/src/sgml/config.sgml | 8 | ||||
| -rw-r--r-- | src/backend/utils/misc/postgresql.conf.sample | 2 | ||||
| -rw-r--r-- | src/include/storage/bufmgr.h | 2 |
3 files changed, 6 insertions, 6 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7ec18bb7627..6cd190ac1a0 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2617,10 +2617,10 @@ include_dir 'conf.d' for maintenance work that is done on behalf of many client sessions. </para> <para> - The default is 10 on supported systems, otherwise 0. This value can - be overridden for tables in a particular tablespace by setting the - tablespace parameter of the same name (see - <xref linkend="sql-altertablespace"/>). + The default is <literal>16</literal> on supported systems, otherwise + <literal>0</literal>. This value can be overridden for tables in a + particular tablespace by setting the tablespace parameter of the same + name (see <xref linkend="sql-altertablespace"/>). </para> </listitem> </varlistentry> diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 43c2ec2153e..8ac2beb177b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -199,7 +199,7 @@ #backend_flush_after = 0 # measured in pages, 0 disables #effective_io_concurrency = 16 # 1-1000; 0 disables prefetching -#maintenance_io_concurrency = 10 # 1-1000; 0 disables prefetching +#maintenance_io_concurrency = 16 # 1-1000; 0 disables prefetching #io_combine_limit = 128kB # usually 1-32 blocks (depends on OS) #io_method = sync # sync (change requires restart) diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h index 79a89f87fcc..7f5def6bada 100644 --- a/src/include/storage/bufmgr.h +++ b/src/include/storage/bufmgr.h @@ -153,7 +153,7 @@ extern PGDLLIMPORT bool track_io_timing; /* only applicable when prefetching is available */ #ifdef USE_PREFETCH #define DEFAULT_EFFECTIVE_IO_CONCURRENCY 16 -#define DEFAULT_MAINTENANCE_IO_CONCURRENCY 10 +#define DEFAULT_MAINTENANCE_IO_CONCURRENCY 16 #else #define DEFAULT_EFFECTIVE_IO_CONCURRENCY 0 #define DEFAULT_MAINTENANCE_IO_CONCURRENCY 0 |