Here is a first attempt at a proper patch set based on the discussion thus
far. I've split it up into several small patches for ease of review, which
is probably a bit excessive. If this ever makes it to commit, they could
likely be combined.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From 612e3ccc66f689a2a16e9dbf027541b71454bad3 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Sat, 13 Apr 2024 15:00:08 -0500
Subject: [PATCH v1 1/4] Rename autovacuum_max_workers to
autovacuum_max_worker_slots.
---
doc/src/sgml/config.sgml | 8 ++++----
doc/src/sgml/maintenance.sgml | 4 ++--
doc/src/sgml/runtime.sgml | 12 ++++++------
src/backend/access/transam/xlog.c | 2 +-
src/backend/postmaster/autovacuum.c | 8 ++++----
src/backend/postmaster/postmaster.c | 2 +-
src/backend/storage/lmgr/proc.c | 6 +++---
src/backend/utils/init/postinit.c | 12 ++++++------
src/backend/utils/misc/guc_tables.c | 6 +++---
src/backend/utils/misc/postgresql.conf.sample | 2 +-
src/include/postmaster/autovacuum.h | 2 +-
src/include/utils/guc_hooks.h | 4 ++--
.../modules/xid_wraparound/t/001_emergency_vacuum.pl | 2 +-
src/test/modules/xid_wraparound/t/003_wraparounds.pl | 2 +-
14 files changed, 36 insertions(+), 36 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d8e1282e12..b4d67a93b6 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1914,7 +1914,7 @@ include_dir 'conf.d'
</para>
<para>
Note that when autovacuum runs, up to
- <xref linkend="guc-autovacuum-max-workers"/> times this memory
+ <xref linkend="guc-autovacuum-max-worker-slots"/> times this memory
may be allocated, so be careful not to set the default value
too high. It may be useful to control for this by separately
setting <xref linkend="guc-autovacuum-work-mem"/>.
@@ -8534,10 +8534,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
</listitem>
</varlistentry>
- <varlistentry id="guc-autovacuum-max-workers" xreflabel="autovacuum_max_workers">
- <term><varname>autovacuum_max_workers</varname> (<type>integer</type>)
+ <varlistentry id="guc-autovacuum-max-worker-slots" xreflabel="autovacuum_max_worker_slots">
+ <term><varname>autovacuum_max_worker_slots</varname> (<type>integer</type>)
<indexterm>
- <primary><varname>autovacuum_max_workers</varname> configuration parameter</primary>
+ <primary><varname>autovacuum_max_worker_slots</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 2bfa05b8bc..7b4b3f0087 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -864,9 +864,9 @@ HINT: Execute a database-wide VACUUM in that database.
seconds. (Therefore, if the installation has <replaceable>N</replaceable> databases,
a new worker will be launched every
<varname>autovacuum_naptime</varname>/<replaceable>N</replaceable> seconds.)
- A maximum of <xref linkend="guc-autovacuum-max-workers"/> worker processes
+ A maximum of <xref linkend="guc-autovacuum-max-worker-slots"/> worker processes
are allowed to run at the same time. If there are more than
- <varname>autovacuum_max_workers</varname> databases to be processed,
+ <varname>autovacuum_max_worker_slots</varname> databases to be processed,
the next database will be processed as soon as the first worker finishes.
Each worker process will check each table within its database and
execute <command>VACUUM</command> and/or <command>ANALYZE</command> as needed.
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 6047b8171d..26a02034c8 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -781,13 +781,13 @@ psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such
<row>
<entry><varname>SEMMNI</varname></entry>
<entry>Maximum number of semaphore identifiers (i.e., sets)</entry>
- <entry>at least <literal>ceil((max_connections + autovacuum_max_workers + max_wal_senders + max_worker_processes + 5) / 16)</literal> plus room for other applications</entry>
+ <entry>at least <literal>ceil((max_connections + autovacuum_max_worker_slots + max_wal_senders + max_worker_processes + 5) / 16)</literal> plus room for other applications</entry>
</row>
<row>
<entry><varname>SEMMNS</varname></entry>
<entry>Maximum number of semaphores system-wide</entry>
- <entry><literal>ceil((max_connections + autovacuum_max_workers + max_wal_senders + max_worker_processes + 5) / 16) * 17</literal> plus room for other applications</entry>
+ <entry><literal>ceil((max_connections + autovacuum_max_worker_slots + max_wal_senders + max_worker_processes + 5) / 16) * 17</literal> plus room for other applications</entry>
</row>
<row>
@@ -838,7 +838,7 @@ psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such
When using System V semaphores,
<productname>PostgreSQL</productname> uses one semaphore per allowed connection
(<xref linkend="guc-max-connections"/>), allowed autovacuum worker process
- (<xref linkend="guc-autovacuum-max-workers"/>) and allowed background
+ (<xref linkend="guc-autovacuum-max-worker-slots"/>) and allowed background
process (<xref linkend="guc-max-worker-processes"/>), in sets of 16.
Each such set will
also contain a 17th semaphore which contains a <quote>magic
@@ -846,13 +846,13 @@ psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such
other applications. The maximum number of semaphores in the system
is set by <varname>SEMMNS</varname>, which consequently must be at least
as high as <varname>max_connections</varname> plus
- <varname>autovacuum_max_workers</varname> plus <varname>max_wal_senders</varname>,
+ <varname>autovacuum_max_worker_slots</varname> plus <varname>max_wal_senders</varname>,
plus <varname>max_worker_processes</varname>, plus one extra for each 16
allowed connections plus workers (see the formula in <xref
linkend="sysvipc-parameters"/>). The parameter <varname>SEMMNI</varname>
determines the limit on the number of semaphore sets that can
exist on the system at one time. Hence this parameter must be at
- least <literal>ceil((max_connections + autovacuum_max_workers + max_wal_senders + max_worker_processes + 5) / 16)</literal>.
+ least <literal>ceil((max_connections + autovacuum_max_worker_slots + max_wal_senders + max_worker_processes + 5) / 16)</literal>.
Lowering the number
of allowed connections is a temporary workaround for failures,
which are usually confusingly worded <quote>No space
@@ -883,7 +883,7 @@ psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such
When using POSIX semaphores, the number of semaphores needed is the
same as for System V, that is one semaphore per allowed connection
(<xref linkend="guc-max-connections"/>), allowed autovacuum worker process
- (<xref linkend="guc-autovacuum-max-workers"/>) and allowed background
+ (<xref linkend="guc-autovacuum-max-worker-slots"/>) and allowed background
process (<xref linkend="guc-max-worker-processes"/>).
On the platforms where this option is preferred, there is no specific
kernel limit on the number of POSIX semaphores.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 34a2c71812..9f9ce5da7d 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5362,7 +5362,7 @@ CheckRequiredParameterValues(void)
*/
if (ArchiveRecoveryRequested && EnableHotStandby)
{
- /* We ignore autovacuum_max_workers when we make this test. */
+ /* We ignore autovacuum_max_worker_slots when we make this test. */
RecoveryRequiresIntParameter("max_connections",
MaxConnections,
ControlFile->MaxConnections);
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index c367ede6f8..af3d1e218e 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -114,7 +114,7 @@
* GUC parameters
*/
bool autovacuum_start_daemon = false;
-int autovacuum_max_workers;
+int autovacuum_max_worker_slots;
int autovacuum_work_mem = -1;
int autovacuum_naptime;
int autovacuum_vac_thresh;
@@ -209,7 +209,7 @@ typedef struct autovac_table
/*-------------
* This struct holds information about a single worker's whereabouts. We keep
* an array of these in shared memory, sized according to
- * autovacuum_max_workers.
+ * autovacuum_max_worker_slots.
*
* wi_links entry into free list or running list
* wi_dboid OID of the database this worker is supposed to work on
@@ -3262,7 +3262,7 @@ AutoVacuumShmemSize(void)
*/
size = sizeof(AutoVacuumShmemStruct);
size = MAXALIGN(size);
- size = add_size(size, mul_size(autovacuum_max_workers,
+ size = add_size(size, mul_size(autovacuum_max_worker_slots,
sizeof(WorkerInfoData)));
return size;
}
@@ -3299,7 +3299,7 @@ AutoVacuumShmemInit(void)
MAXALIGN(sizeof(AutoVacuumShmemStruct)));
/* initialize the WorkerInfo free list */
- for (i = 0; i < autovacuum_max_workers; i++)
+ for (i = 0; i < autovacuum_max_worker_slots; i++)
{
dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
&worker[i].wi_links);
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 7f3170a8f0..0faec534c0 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_max_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 162b1f919d..84339655e9 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -142,7 +142,7 @@ ProcGlobalSemas(void)
* So, now we grab enough semaphores to support the desired max number
* of backends immediately at initialization --- if the sysadmin has set
* MaxConnections, max_worker_processes, max_wal_senders, or
- * autovacuum_max_workers higher than his kernel will support, he'll
+ * autovacuum_max_worker_slots higher than his kernel will support, he'll
* find out sooner rather than later.
*
* Another reason for creating semaphores here is that the semaphore
@@ -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_max_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_max_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 0805398e24..c05653262f 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -577,7 +577,7 @@ InitializeMaxBackends(void)
Assert(MaxBackends == 0);
/* the extra unit accounts for the autovacuum launcher */
- MaxBackends = MaxConnections + autovacuum_max_workers + 1 +
+ MaxBackends = MaxConnections + autovacuum_max_worker_slots + 1 +
max_worker_processes + max_wal_senders;
/* internal error because the values were all checked previously */
@@ -591,17 +591,17 @@ InitializeMaxBackends(void)
bool
check_max_connections(int *newval, void **extra, GucSource source)
{
- if (*newval + autovacuum_max_workers + 1 +
+ if (*newval + autovacuum_max_worker_slots + 1 +
max_worker_processes + max_wal_senders > MAX_BACKENDS)
return false;
return true;
}
/*
- * GUC check_hook for autovacuum_max_workers
+ * GUC check_hook for autovacuum_max_worker_slots
*/
bool
-check_autovacuum_max_workers(int *newval, void **extra, GucSource source)
+check_autovacuum_max_worker_slots(int *newval, void **extra, GucSource source)
{
if (MaxConnections + *newval + 1 +
max_worker_processes + max_wal_senders > MAX_BACKENDS)
@@ -615,7 +615,7 @@ check_autovacuum_max_workers(int *newval, void **extra, GucSource source)
bool
check_max_worker_processes(int *newval, void **extra, GucSource source)
{
- if (MaxConnections + autovacuum_max_workers + 1 +
+ if (MaxConnections + autovacuum_max_worker_slots + 1 +
*newval + max_wal_senders > MAX_BACKENDS)
return false;
return true;
@@ -627,7 +627,7 @@ check_max_worker_processes(int *newval, void **extra, GucSource source)
bool
check_max_wal_senders(int *newval, void **extra, GucSource source)
{
- if (MaxConnections + autovacuum_max_workers + 1 +
+ if (MaxConnections + autovacuum_max_worker_slots + 1 +
max_worker_processes + *newval > MAX_BACKENDS)
return false;
return true;
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index c68fdc008b..92dea7061a 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -3402,13 +3402,13 @@ struct config_int ConfigureNamesInt[] =
},
{
/* see max_connections */
- {"autovacuum_max_workers", PGC_POSTMASTER, AUTOVACUUM,
+ {"autovacuum_max_worker_slots", PGC_POSTMASTER, AUTOVACUUM,
gettext_noop("Sets the maximum number of simultaneously running autovacuum worker processes."),
NULL
},
- &autovacuum_max_workers,
+ &autovacuum_max_worker_slots,
3, 1, MAX_BACKENDS,
- check_autovacuum_max_workers, NULL, NULL
+ check_autovacuum_max_worker_slots, NULL, NULL
},
{
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 2166ea4a87..c37767cecf 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -658,7 +658,7 @@
#autovacuum = on # Enable autovacuum subprocess? 'on'
# requires track_counts to also be on.
-#autovacuum_max_workers = 3 # max number of autovacuum subprocesses
+#autovacuum_max_worker_slots = 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
diff --git a/src/include/postmaster/autovacuum.h b/src/include/postmaster/autovacuum.h
index cae1e8b329..754d04485d 100644
--- a/src/include/postmaster/autovacuum.h
+++ b/src/include/postmaster/autovacuum.h
@@ -28,7 +28,7 @@ typedef enum
/* GUC variables */
extern PGDLLIMPORT bool autovacuum_start_daemon;
-extern PGDLLIMPORT int autovacuum_max_workers;
+extern PGDLLIMPORT int autovacuum_max_worker_slots;
extern PGDLLIMPORT int autovacuum_work_mem;
extern PGDLLIMPORT int autovacuum_naptime;
extern PGDLLIMPORT int autovacuum_vac_thresh;
diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h
index d64dc5fcdb..22d4c50bc6 100644
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -29,8 +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_max_worker_slots(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,
diff --git a/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl b/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
index 37550b67a4..f9cdd50c19 100644
--- a/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
+++ b/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
@@ -21,7 +21,7 @@ $node->append_conf(
autovacuum = off # run autovacuum only when to anti wraparound
autovacuum_naptime = 1s
# so it's easier to verify the order of operations
-autovacuum_max_workers = 1
+autovacuum_max_worker_slots = 1
log_autovacuum_min_duration = 0
]);
$node->start;
diff --git a/src/test/modules/xid_wraparound/t/003_wraparounds.pl b/src/test/modules/xid_wraparound/t/003_wraparounds.pl
index 88063b4b52..99f76229d5 100644
--- a/src/test/modules/xid_wraparound/t/003_wraparounds.pl
+++ b/src/test/modules/xid_wraparound/t/003_wraparounds.pl
@@ -24,7 +24,7 @@ $node->append_conf(
autovacuum = off # run autovacuum only when to anti wraparound
autovacuum_naptime = 1s
# so it's easier to verify the order of operations
-autovacuum_max_workers = 1
+autovacuum_max_worker_slots = 1
log_autovacuum_min_duration = 0
]);
$node->start;
--
2.25.1
>From 2da218f260afdd68820ec2708fe7279ec2339d8a Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Sat, 13 Apr 2024 21:48:53 -0500
Subject: [PATCH v1 2/4] Convert autovacuum's free workers list to a dclist.
---
src/backend/postmaster/autovacuum.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index af3d1e218e..e925eff1e4 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -289,7 +289,7 @@ typedef struct
{
sig_atomic_t av_signal[AutoVacNumSignals];
pid_t av_launcherpid;
- dlist_head av_freeWorkers;
+ dclist_head av_freeWorkers;
dlist_head av_runningWorkers;
WorkerInfo av_startingWorker;
AutoVacuumWorkItem av_workItems[NUM_WORKITEMS];
@@ -575,7 +575,7 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len)
* wakening conditions.
*/
- launcher_determine_sleep(!dlist_is_empty(&AutoVacuumShmem->av_freeWorkers),
+ launcher_determine_sleep(!dclist_is_empty(&AutoVacuumShmem->av_freeWorkers),
false, &nap);
/*
@@ -636,7 +636,7 @@ 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 = !dclist_is_empty(&AutoVacuumShmem->av_freeWorkers);
if (AutoVacuumShmem->av_startingWorker != NULL)
{
@@ -679,8 +679,8 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len)
worker->wi_sharedrel = false;
worker->wi_proc = NULL;
worker->wi_launchtime = 0;
- dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
- &worker->wi_links);
+ dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
+ &worker->wi_links);
AutoVacuumShmem->av_startingWorker = NULL;
ereport(WARNING,
errmsg("autovacuum worker took too long to start; canceled"));
@@ -1087,7 +1087,7 @@ do_start_worker(void)
/* return quickly when there are no free workers */
LWLockAcquire(AutovacuumLock, LW_SHARED);
- if (dlist_is_empty(&AutoVacuumShmem->av_freeWorkers))
+ if (dclist_is_empty(&AutoVacuumShmem->av_freeWorkers))
{
LWLockRelease(AutovacuumLock);
return InvalidOid;
@@ -1240,7 +1240,7 @@ do_start_worker(void)
* Get a worker entry from the freelist. We checked above, so there
* really should be a free slot.
*/
- wptr = dlist_pop_head_node(&AutoVacuumShmem->av_freeWorkers);
+ wptr = dclist_pop_head_node(&AutoVacuumShmem->av_freeWorkers);
worker = dlist_container(WorkerInfoData, wi_links, wptr);
worker->wi_dboid = avdb->adw_datid;
@@ -1609,8 +1609,8 @@ FreeWorkerInfo(int code, Datum arg)
MyWorkerInfo->wi_proc = NULL;
MyWorkerInfo->wi_launchtime = 0;
pg_atomic_clear_flag(&MyWorkerInfo->wi_dobalance);
- dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
- &MyWorkerInfo->wi_links);
+ dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
+ &MyWorkerInfo->wi_links);
/* not mine anymore */
MyWorkerInfo = NULL;
@@ -3289,7 +3289,7 @@ AutoVacuumShmemInit(void)
Assert(!found);
AutoVacuumShmem->av_launcherpid = 0;
- dlist_init(&AutoVacuumShmem->av_freeWorkers);
+ dclist_init(&AutoVacuumShmem->av_freeWorkers);
dlist_init(&AutoVacuumShmem->av_runningWorkers);
AutoVacuumShmem->av_startingWorker = NULL;
memset(AutoVacuumShmem->av_workItems, 0,
@@ -3301,8 +3301,8 @@ AutoVacuumShmemInit(void)
/* initialize the WorkerInfo free list */
for (i = 0; i < autovacuum_max_worker_slots; i++)
{
- dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
- &worker[i].wi_links);
+ dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
+ &worker[i].wi_links);
pg_atomic_init_flag(&worker[i].wi_dobalance);
}
--
2.25.1
>From b54ccd2f461fd325037f13806be16bea58dad321 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Sun, 14 Apr 2024 09:04:01 -0500
Subject: [PATCH v1 3/4] Move free autovacuum worker checks to a helper
function.
---
src/backend/postmaster/autovacuum.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index e925eff1e4..f80365faff 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -347,6 +347,7 @@ 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);
@@ -575,8 +576,7 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len)
* wakening conditions.
*/
- launcher_determine_sleep(!dclist_is_empty(&AutoVacuumShmem->av_freeWorkers),
- false, &nap);
+ launcher_determine_sleep(av_worker_available(), false, &nap);
/*
* Wait until naptime expires or we get some type of signal (all the
@@ -636,7 +636,7 @@ AutoVacLauncherMain(char *startup_data, size_t startup_data_len)
current_time = GetCurrentTimestamp();
LWLockAcquire(AutovacuumLock, LW_SHARED);
- can_launch = !dclist_is_empty(&AutoVacuumShmem->av_freeWorkers);
+ can_launch = av_worker_available();
if (AutoVacuumShmem->av_startingWorker != NULL)
{
@@ -1087,7 +1087,7 @@ do_start_worker(void)
/* return quickly when there are no free workers */
LWLockAcquire(AutovacuumLock, LW_SHARED);
- if (dclist_is_empty(&AutoVacuumShmem->av_freeWorkers))
+ if (!av_worker_available())
{
LWLockRelease(AutovacuumLock);
return InvalidOid;
@@ -3338,3 +3338,14 @@ check_autovacuum_work_mem(int *newval, void **extra, GucSource source)
return true;
}
+
+/*
+ * Returns whether there is a free autovacuum worker slot available.
+ */
+static bool
+av_worker_available(void)
+{
+ const dclist_head *freelist = &AutoVacuumShmem->av_freeWorkers;
+
+ return dclist_count(freelist) > 0;
+}
--
2.25.1
>From 259615d1b03ce2f27ddd17d9210147e39cd7a4cf Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Sat, 13 Apr 2024 21:42:33 -0500
Subject: [PATCH v1 4/4] Reintroduce autovacuum_max_workers as a PGC_SIGHUP
parameter.
---
doc/src/sgml/config.sgml | 25 ++++++++++++++++++-
doc/src/sgml/maintenance.sgml | 4 +--
src/backend/postmaster/autovacuum.c | 4 ++-
src/backend/utils/misc/guc_tables.c | 15 ++++++++---
src/backend/utils/misc/postgresql.conf.sample | 3 ++-
src/include/postmaster/autovacuum.h | 1 +
.../xid_wraparound/t/001_emergency_vacuum.pl | 2 +-
.../xid_wraparound/t/003_wraparounds.pl | 2 +-
8 files changed, 46 insertions(+), 10 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b4d67a93b6..569b090593 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1914,7 +1914,7 @@ include_dir 'conf.d'
</para>
<para>
Note that when autovacuum runs, up to
- <xref linkend="guc-autovacuum-max-worker-slots"/> times this memory
+ <xref linkend="guc-autovacuum-max-workers"/> times this memory
may be allocated, so be careful not to set the default value
too high. It may be useful to control for this by separately
setting <xref linkend="guc-autovacuum-work-mem"/>.
@@ -8540,12 +8540,35 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
<primary><varname>autovacuum_max_worker_slots</varname> configuration parameter</primary>
</indexterm>
</term>
+ <listitem>
+ <para>
+ Specifies the number of backend slots to reserve for autovacuum worker
+ processes. The default is 32. This parameter can only be set at server
+ start.
+ </para>
+ <para>
+ Note that the value of <xref linkend="guc-autovacuum-max-workers"/> is
+ silently capped to this value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry id="guc-autovacuum-max-workers" xreflabel="autovacuum_max_workers">
+ <term><varname>autovacuum_max_workers</varname> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>autovacuum_max_workers</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
<listitem>
<para>
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.
</para>
+ <para>
+ Note that this value is silently capped to the value of
+ <xref linkend="guc-autovacuum-max-worker-slots"/>.
+ </para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 7b4b3f0087..2bfa05b8bc 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -864,9 +864,9 @@ HINT: Execute a database-wide VACUUM in that database.
seconds. (Therefore, if the installation has <replaceable>N</replaceable> databases,
a new worker will be launched every
<varname>autovacuum_naptime</varname>/<replaceable>N</replaceable> seconds.)
- A maximum of <xref linkend="guc-autovacuum-max-worker-slots"/> worker processes
+ A maximum of <xref linkend="guc-autovacuum-max-workers"/> worker processes
are allowed to run at the same time. If there are more than
- <varname>autovacuum_max_worker_slots</varname> databases to be processed,
+ <varname>autovacuum_max_workers</varname> databases to be processed,
the next database will be processed as soon as the first worker finishes.
Each worker process will check each table within its database and
execute <command>VACUUM</command> and/or <command>ANALYZE</command> as needed.
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index f80365faff..ed7e2b462f 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -115,6 +115,7 @@
*/
bool autovacuum_start_daemon = false;
int autovacuum_max_worker_slots;
+int autovacuum_max_workers;
int autovacuum_work_mem = -1;
int autovacuum_naptime;
int autovacuum_vac_thresh;
@@ -3346,6 +3347,7 @@ static bool
av_worker_available(void)
{
const dclist_head *freelist = &AutoVacuumShmem->av_freeWorkers;
+ int reserved_slots = autovacuum_max_worker_slots - autovacuum_max_workers;
- return dclist_count(freelist) > 0;
+ return dclist_count(freelist) > Max(0, reserved_slots);
}
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 92dea7061a..92d4d10fe9 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -3403,13 +3403,22 @@ struct config_int ConfigureNamesInt[] =
{
/* see max_connections */
{"autovacuum_max_worker_slots", PGC_POSTMASTER, AUTOVACUUM,
- gettext_noop("Sets the maximum number of simultaneously running autovacuum worker processes."),
- NULL
+ gettext_noop("Sets the number of backend slots to allocate for autovacuum workers."),
+ gettext_noop("autovacuum_max_workers is silently capped to this value.")
},
&autovacuum_max_worker_slots,
- 3, 1, MAX_BACKENDS,
+ 32, 1, MAX_BACKENDS,
check_autovacuum_max_worker_slots, NULL, NULL
},
+ {
+ {"autovacuum_max_workers", PGC_SIGHUP, AUTOVACUUM,
+ gettext_noop("Sets the maximum number of simultaneously running autovacuum worker processes."),
+ gettext_noop("This value is silently capped to autovacuum_max_worker_slots.")
+ },
+ &autovacuum_max_workers,
+ 3, 1, MAX_BACKENDS,
+ NULL, NULL, NULL
+ },
{
{"max_parallel_maintenance_workers", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index c37767cecf..c46d245153 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -658,8 +658,9 @@
#autovacuum = on # Enable autovacuum subprocess? 'on'
# requires track_counts to also be on.
-#autovacuum_max_worker_slots = 3 # max number of autovacuum subprocesses
+autovacuum_max_worker_slots = 32 # autovacuum worker slots to allocate
# (change requires restart)
+#autovacuum_max_workers = 3 # max number of autovacuum subprocesses
#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 754d04485d..598782fd34 100644
--- a/src/include/postmaster/autovacuum.h
+++ b/src/include/postmaster/autovacuum.h
@@ -29,6 +29,7 @@ typedef enum
/* GUC variables */
extern PGDLLIMPORT bool autovacuum_start_daemon;
extern PGDLLIMPORT int autovacuum_max_worker_slots;
+extern PGDLLIMPORT int autovacuum_max_workers;
extern PGDLLIMPORT int autovacuum_work_mem;
extern PGDLLIMPORT int autovacuum_naptime;
extern PGDLLIMPORT int autovacuum_vac_thresh;
diff --git a/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl b/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
index f9cdd50c19..37550b67a4 100644
--- a/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
+++ b/src/test/modules/xid_wraparound/t/001_emergency_vacuum.pl
@@ -21,7 +21,7 @@ $node->append_conf(
autovacuum = off # run autovacuum only when to anti wraparound
autovacuum_naptime = 1s
# so it's easier to verify the order of operations
-autovacuum_max_worker_slots = 1
+autovacuum_max_workers = 1
log_autovacuum_min_duration = 0
]);
$node->start;
diff --git a/src/test/modules/xid_wraparound/t/003_wraparounds.pl b/src/test/modules/xid_wraparound/t/003_wraparounds.pl
index 99f76229d5..88063b4b52 100644
--- a/src/test/modules/xid_wraparound/t/003_wraparounds.pl
+++ b/src/test/modules/xid_wraparound/t/003_wraparounds.pl
@@ -24,7 +24,7 @@ $node->append_conf(
autovacuum = off # run autovacuum only when to anti wraparound
autovacuum_naptime = 1s
# so it's easier to verify the order of operations
-autovacuum_max_worker_slots = 1
+autovacuum_max_workers = 1
log_autovacuum_min_duration = 0
]);
$node->start;
--
2.25.1
