From 48f7d56b99f2d98533c8767d5891a78c8411872d Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Fri, 21 Jun 2024 15:29:28 -0500 Subject: [PATCH v5 3/3] allow changing autovacuum_max_workers without restarting --- doc/src/sgml/config.sgml | 8 +++- src/backend/postmaster/autovacuum.c | 25 ++++++++++--- src/backend/postmaster/postmaster.c | 2 +- src/backend/storage/lmgr/proc.c | 4 +- src/backend/utils/init/postinit.c | 37 +++++++++++++++++-- src/backend/utils/misc/guc_tables.c | 4 +- src/backend/utils/misc/postgresql.conf.sample | 1 - src/include/postmaster/autovacuum.h | 1 + src/include/utils/guc_hooks.h | 2 + 9 files changed, 69 insertions(+), 15 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 087385cb4e..289c2b63c4 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -8554,7 +8554,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Specifies the maximum number of autovacuum processes (other than the autovacuum launcher) that may be running at any one time. The default - is three. This parameter can only be set at server start. + is three. This parameter can only be set in the + postgresql.conf file or on the server command line. + + + This parameter is limited to 50% of + (but no less than 1 or greater + than 64). diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 9a925a10cd..8bf95981a0 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -130,6 +130,7 @@ double autovacuum_vac_cost_delay; int autovacuum_vac_cost_limit; int Log_autovacuum_min_duration = 600000; +int autovacuum_worker_slots = -1; /* the minimum allowed time between two awakenings of the launcher */ #define MIN_AUTOVAC_SLEEPTIME 100.0 /* milliseconds */ @@ -347,6 +348,7 @@ static void autovac_report_activity(autovac_table *tab); static void autovac_report_workitem(AutoVacuumWorkItem *workitem, const char *nspname, const char *relname); static void avl_sigusr2_handler(SIGNAL_ARGS); +static bool av_worker_available(void); @@ -575,7 +577,7 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len) * wakening conditions. */ - launcher_determine_sleep(!dlist_is_empty(&AutoVacuumShmem->av_freeWorkers), + launcher_determine_sleep(av_worker_available(), false, &nap); /* @@ -636,7 +638,7 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len) current_time = GetCurrentTimestamp(); LWLockAcquire(AutovacuumLock, LW_SHARED); - can_launch = !dlist_is_empty(&AutoVacuumShmem->av_freeWorkers); + can_launch = av_worker_available(); if (AutoVacuumShmem->av_startingWorker != NULL) { @@ -1087,7 +1089,7 @@ do_start_worker(void) /* return quickly when there are no free workers */ LWLockAcquire(AutovacuumLock, LW_SHARED); - if (dlist_is_empty(&AutoVacuumShmem->av_freeWorkers)) + if (!av_worker_available()) { LWLockRelease(AutovacuumLock); return InvalidOid; @@ -3265,7 +3267,7 @@ AutoVacuumShmemSize(void) */ size = sizeof(AutoVacuumShmemStruct); size = MAXALIGN(size); - size = add_size(size, mul_size(autovacuum_max_workers, + size = add_size(size, mul_size(autovacuum_worker_slots, sizeof(WorkerInfoData))); return size; } @@ -3302,7 +3304,7 @@ AutoVacuumShmemInit(void) MAXALIGN(sizeof(AutoVacuumShmemStruct))); /* initialize the WorkerInfo free list */ - for (i = 0; i < autovacuum_max_workers; i++) + for (i = 0; i < autovacuum_worker_slots; i++) { dlist_push_head(&AutoVacuumShmem->av_freeWorkers, &worker[i].wi_links); @@ -3341,3 +3343,16 @@ check_autovacuum_work_mem(int *newval, void **extra, GucSource source) return true; } + +static bool +av_worker_available(void) +{ + int reserved = autovacuum_worker_slots - autovacuum_max_workers; + int count = 0; + dlist_iter iter; + + dlist_foreach(iter, &AutoVacuumShmem->av_freeWorkers) + count++; + + return count > reserved; +} diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index bf0241aed0..2588a68fbc 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -4144,7 +4144,7 @@ CreateOptsFile(int argc, char *argv[], char *fullprogname) int MaxLivePostmasterChildren(void) { - return 2 * (MaxConnections + autovacuum_max_workers + 1 + + return 2 * (MaxConnections + autovacuum_worker_slots + 1 + max_wal_senders + max_worker_processes); } diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index ce29da9012..10e0b681cf 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -242,13 +242,13 @@ InitProcGlobal(void) dlist_push_tail(&ProcGlobal->freeProcs, &proc->links); proc->procgloballist = &ProcGlobal->freeProcs; } - else if (i < MaxConnections + autovacuum_max_workers + 1) + else if (i < MaxConnections + autovacuum_worker_slots + 1) { /* PGPROC for AV launcher/worker, add to autovacFreeProcs list */ dlist_push_tail(&ProcGlobal->autovacFreeProcs, &proc->links); proc->procgloballist = &ProcGlobal->autovacFreeProcs; } - else if (i < MaxConnections + autovacuum_max_workers + 1 + max_worker_processes) + else if (i < MaxConnections + autovacuum_worker_slots + 1 + max_worker_processes) { /* PGPROC for bgworker, add to bgworkerFreeProcs list */ dlist_push_tail(&ProcGlobal->bgworkerFreeProcs, &proc->links); diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 8a629982c4..d206dd1533 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -576,20 +576,51 @@ InitializeMaxBackends(void) { Assert(MaxBackends == 0); + autovacuum_worker_slots = Max(1, Min(64, MaxConnections / 2)); + if (autovacuum_max_workers > autovacuum_worker_slots) + { + /* keep in sync with check_autovacuum_max_workers() */ + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid setting for \"autovacuum_max_workers\""), + errdetail("\"autovacuum_max_workers\" (%d) is limited to 50%% of \"max_connections\" (but no less than 1 or greater than 64) (%d)", + autovacuum_max_workers, autovacuum_worker_slots))); + } + /* the extra unit accounts for the autovacuum launcher */ - MaxBackends = MaxConnections + autovacuum_max_workers + 1 + + MaxBackends = MaxConnections + autovacuum_worker_slots + 1 + max_worker_processes + max_wal_senders; if (MaxBackends > MAX_BACKENDS) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("too many backends configured"), - errdetail("\"max_connections\" (%d) plus \"autovacuum_max_workers\" (%d) plus \"max_worker_processes\" (%d) plus \"max_wal_senders\" (%d) must be less than %d.", - MaxConnections, autovacuum_max_workers, + errdetail("\"max_connections\" (%d) plus autovacuum worker slots (%d) plus \"max_worker_processes\" (%d) plus \"max_wal_senders\" (%d) must be less than %d.", + MaxConnections, autovacuum_worker_slots, max_worker_processes, max_wal_senders, MAX_BACKENDS - 1))); } +/* + * GUC check_hook for autovacuum_max_workers + */ +bool +check_autovacuum_max_workers(int *newval, void **extra, GucSource source) +{ + /* + * If autovacuum_worker_slots has not yet been initialized, just return + * true. We'll fail startup in PostmasterMain() if needed. + */ + if (autovacuum_worker_slots == -1 || *newval <= autovacuum_worker_slots) + return true; + + /* keep in sync with matching error message in InitializeMaxBackends() */ + GUC_check_errmsg("invalid setting for \"autovacuum_max_workers\""); + GUC_check_errdetail("\"autovacuum_max_workers\" (%d) is limited to 50%% of \"max_connections\" (but no less than 1 or greater than 64) (%d)", + autovacuum_max_workers, autovacuum_worker_slots); + return false; +} + /* * Early initialization of a backend (either standalone or under postmaster). * This happens even before InitPostgres. diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c index 57df7767ad..f1babff58e 100644 --- a/src/backend/utils/misc/guc_tables.c +++ b/src/backend/utils/misc/guc_tables.c @@ -3393,13 +3393,13 @@ struct config_int ConfigureNamesInt[] = }, { /* see max_connections */ - {"autovacuum_max_workers", PGC_POSTMASTER, AUTOVACUUM, + {"autovacuum_max_workers", PGC_SIGHUP, AUTOVACUUM, gettext_noop("Sets the maximum number of simultaneously running autovacuum worker processes."), NULL }, &autovacuum_max_workers, 3, 1, MAX_BACKENDS, - NULL, NULL, NULL + check_autovacuum_max_workers, NULL, NULL }, { diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e0567de219..fec719fe79 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -659,7 +659,6 @@ #autovacuum = on # Enable autovacuum subprocess? 'on' # requires track_counts to also be on. #autovacuum_max_workers = 3 # max number of autovacuum subprocesses - # (change requires restart) #autovacuum_naptime = 1min # time between autovacuum runs #autovacuum_vacuum_threshold = 50 # min number of row updates before # vacuum diff --git a/src/include/postmaster/autovacuum.h b/src/include/postmaster/autovacuum.h index cae1e8b329..2b2aa1b713 100644 --- a/src/include/postmaster/autovacuum.h +++ b/src/include/postmaster/autovacuum.h @@ -46,6 +46,7 @@ extern PGDLLIMPORT int autovacuum_vac_cost_limit; extern PGDLLIMPORT int AutovacuumLauncherPid; extern PGDLLIMPORT int Log_autovacuum_min_duration; +extern PGDLLIMPORT int autovacuum_worker_slots; /* Status inquiry functions */ extern bool AutoVacuumingActive(void); diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h index 6304f0679b..b3e1f9f2cb 100644 --- a/src/include/utils/guc_hooks.h +++ b/src/include/utils/guc_hooks.h @@ -29,6 +29,8 @@ extern bool check_application_name(char **newval, void **extra, GucSource source); extern void assign_application_name(const char *newval, void *extra); extern const char *show_archive_command(void); +extern bool check_autovacuum_max_workers(int *newval, void **extra, + GucSource source); extern bool check_autovacuum_work_mem(int *newval, void **extra, GucSource source); extern bool check_vacuum_buffer_usage_limit(int *newval, void **extra, -- 2.39.3 (Apple Git-146)