From 8f98d20223aaf9a3c7965bbf6e64a0ff02ea1931 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Wed, 19 Mar 2025 10:15:20 -0400 Subject: [PATCH v2.12 13/28] Enable IO concurrency on all systems Previously effective_io_concurrency and maintenance_io_concurrency could not be set above 0 on machines without fadvise support. AIO enables IO concurrency without such support. Currently only subsystems using the read stream API will take advantage of this. Other users of maintenance_io_concurrency (like recovery prefetching) which leverage OS advice directly will not benefit from this change. In those cases, maintenance_io_concurrency will have no effect on I/O behavior. Author: Melanie Plageman Discussion: https://postgr.es/m/CAAKRu_atGgZePo=_g6T3cNtfMf0QxpvoUh5OUqa_cnPdhLd=gw@mail.gmail.com --- src/include/storage/bufmgr.h | 6 ---- src/include/utils/guc_hooks.h | 4 --- src/backend/access/common/reloptions.c | 8 ----- src/backend/commands/variable.c | 30 ------------------- src/backend/utils/misc/guc_tables.c | 4 +-- src/backend/utils/misc/postgresql.conf.sample | 6 ++-- src/bin/initdb/initdb.c | 5 ---- doc/src/sgml/config.sgml | 15 +++++----- doc/src/sgml/ref/alter_tablespace.sgml | 2 +- doc/src/sgml/ref/create_tablespace.sgml | 2 +- 10 files changed, 14 insertions(+), 68 deletions(-) diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h index 7abb3bdfd9d..784df8b00cb 100644 --- a/src/include/storage/bufmgr.h +++ b/src/include/storage/bufmgr.h @@ -156,14 +156,8 @@ extern PGDLLIMPORT int bgwriter_lru_maxpages; extern PGDLLIMPORT double bgwriter_lru_multiplier; 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 16 -#else -#define DEFAULT_EFFECTIVE_IO_CONCURRENCY 0 -#define DEFAULT_MAINTENANCE_IO_CONCURRENCY 0 -#endif extern PGDLLIMPORT int effective_io_concurrency; extern PGDLLIMPORT int maintenance_io_concurrency; diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h index 0f1e74f96c9..799fa7ace68 100644 --- a/src/include/utils/guc_hooks.h +++ b/src/include/utils/guc_hooks.h @@ -61,8 +61,6 @@ extern bool check_default_text_search_config(char **newval, void **extra, GucSou extern void assign_default_text_search_config(const char *newval, void *extra); extern bool check_default_with_oids(bool *newval, void **extra, GucSource source); -extern bool check_effective_io_concurrency(int *newval, void **extra, - GucSource source); extern bool check_huge_page_size(int *newval, void **extra, GucSource source); extern void assign_io_method(int newval, void *extra); extern bool check_io_max_concurrency(int *newval, void **extra, GucSource source); @@ -83,8 +81,6 @@ extern bool check_log_stats(bool *newval, void **extra, GucSource source); extern bool check_log_timezone(char **newval, void **extra, GucSource source); extern void assign_log_timezone(const char *newval, void *extra); extern const char *show_log_timezone(void); -extern bool check_maintenance_io_concurrency(int *newval, void **extra, - GucSource source); extern void assign_maintenance_io_concurrency(int newval, void *extra); extern void assign_io_max_combine_limit(int newval, void *extra); extern void assign_io_combine_limit(int newval, void *extra); diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c index 645b5c00467..46c1dce222d 100644 --- a/src/backend/access/common/reloptions.c +++ b/src/backend/access/common/reloptions.c @@ -361,11 +361,7 @@ static relopt_int intRelOpts[] = RELOPT_KIND_TABLESPACE, ShareUpdateExclusiveLock }, -#ifdef USE_PREFETCH -1, 0, MAX_IO_CONCURRENCY -#else - 0, 0, 0 -#endif }, { { @@ -374,11 +370,7 @@ static relopt_int intRelOpts[] = RELOPT_KIND_TABLESPACE, ShareUpdateExclusiveLock }, -#ifdef USE_PREFETCH -1, 0, MAX_IO_CONCURRENCY -#else - 0, 0, 0 -#endif }, { { diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index f550a3c0c63..d3567aa7f27 100644 --- a/src/backend/commands/variable.c +++ b/src/backend/commands/variable.c @@ -1145,7 +1145,6 @@ check_cluster_name(char **newval, void **extra, GucSource source) void assign_maintenance_io_concurrency(int newval, void *extra) { -#ifdef USE_PREFETCH /* * Reconfigure recovery prefetching, because a setting it depends on * changed. @@ -1153,7 +1152,6 @@ assign_maintenance_io_concurrency(int newval, void *extra) maintenance_io_concurrency = newval; if (AmStartupProcess()) XLogPrefetchReconfigure(); -#endif } /* @@ -1249,34 +1247,6 @@ check_default_with_oids(bool *newval, void **extra, GucSource source) return true; } -bool -check_effective_io_concurrency(int *newval, void **extra, GucSource source) -{ -#ifndef USE_PREFETCH - if (*newval != 0) - { - GUC_check_errdetail("\"%s\" must be set to 0 on platforms that lack support for issuing read-ahead advice.", - "effective_io_concurrency"); - return false; - } -#endif /* USE_PREFETCH */ - return true; -} - -bool -check_maintenance_io_concurrency(int *newval, void **extra, GucSource source) -{ -#ifndef USE_PREFETCH - if (*newval != 0) - { - GUC_check_errdetail("\"%s\" must be set to 0 on platforms that lack support for issuing read-ahead advice.", - "maintenance_io_concurrency"); - return false; - } -#endif /* USE_PREFETCH */ - return true; -} - bool check_ssl(bool *newval, void **extra, GucSource source) { diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c index 989825d3a9c..5d729102f46 100644 --- a/src/backend/utils/misc/guc_tables.c +++ b/src/backend/utils/misc/guc_tables.c @@ -3245,7 +3245,7 @@ struct config_int ConfigureNamesInt[] = &effective_io_concurrency, DEFAULT_EFFECTIVE_IO_CONCURRENCY, 0, MAX_IO_CONCURRENCY, - check_effective_io_concurrency, NULL, NULL + NULL, NULL, NULL }, { @@ -3259,7 +3259,7 @@ struct config_int ConfigureNamesInt[] = &maintenance_io_concurrency, DEFAULT_MAINTENANCE_IO_CONCURRENCY, 0, MAX_IO_CONCURRENCY, - check_maintenance_io_concurrency, assign_maintenance_io_concurrency, + NULL, assign_maintenance_io_concurrency, NULL }, diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2246ccb85a7..771fe4cbe35 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -198,11 +198,11 @@ # - I/O - #backend_flush_after = 0 # measured in pages, 0 disables -#effective_io_concurrency = 16 # 1-1000; 0 disables prefetching -#maintenance_io_concurrency = 16 # 1-1000; 0 disables prefetching +#effective_io_concurrency = 16 # 1-1000; 0 disables issuing multiple simultaneous IO requests +#maintenance_io_concurrency = 16 # 1-1000; same as effective_io_concurrency #io_max_combine_limit = 128kB # usually 1-128 blocks (depends on OS) # (change requires restart) -#io_combine_limit = 128kB # usually 1-128 blocks (depends on OS) +#io_combine_limit = 128kB # usually 1-32 blocks (depends on OS) #io_method = worker # worker, io_uring, sync # (change requires restart) diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c index 21a0fe3ecd9..b9d75799ee0 100644 --- a/src/bin/initdb/initdb.c +++ b/src/bin/initdb/initdb.c @@ -1401,11 +1401,6 @@ setup_config(void) repltok, true); #endif -#ifndef USE_PREFETCH - conflines = replace_guc_value(conflines, "effective_io_concurrency", - "0", true); -#endif - #ifdef WIN32 conflines = replace_guc_value(conflines, "update_process_title", "off", true); diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 13773c05ff4..e447ade5c2b 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2585,8 +2585,7 @@ include_dir 'conf.d' session attempts to initiate in parallel. The allowed range is 1 to 1000, or 0 to disable issuance of asynchronous I/O requests. - The default is 16 on supported systems, otherwise - 0. + The default is 16. @@ -2597,8 +2596,8 @@ include_dir 'conf.d' - On systems without prefetch advice support, attempting to configure - any value other than 0 will error out. + On systems with prefetch advice support, + effective_io_concurrency also controls the prefetch distance. @@ -2621,10 +2620,10 @@ include_dir 'conf.d' for maintenance work that is done on behalf of many client sessions. - The default is 16 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 ). + The default is 16. This value can be overridden + for tables in a particular tablespace by setting the tablespace + parameter of the same name (see ). diff --git a/doc/src/sgml/ref/alter_tablespace.sgml b/doc/src/sgml/ref/alter_tablespace.sgml index 6ec863400d1..d0e08089ddb 100644 --- a/doc/src/sgml/ref/alter_tablespace.sgml +++ b/doc/src/sgml/ref/alter_tablespace.sgml @@ -88,7 +88,7 @@ ALTER TABLESPACE name RESET ( , , diff --git a/doc/src/sgml/ref/create_tablespace.sgml b/doc/src/sgml/ref/create_tablespace.sgml index 9d5ab025261..b77e774c53f 100644 --- a/doc/src/sgml/ref/create_tablespace.sgml +++ b/doc/src/sgml/ref/create_tablespace.sgml @@ -110,7 +110,7 @@ CREATE TABLESPACE tablespace_name and maintenance_io_concurrency. Setting these values for a particular tablespace will override the planner's usual estimate of the cost of reading pages from tables in - that tablespace, and the executor's prefetching behavior, as established + that tablespace, and how many concurrent I/Os are issued, as established by the configuration parameters of the same name (see , , -- 2.48.1.76.g4e746b1a31.dirty