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bgworker.h File Reference
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Data Structures

struct  BackgroundWorker
 

Macros

#define BGWORKER_SHMEM_ACCESS   0x0001
 
#define BGWORKER_BACKEND_DATABASE_CONNECTION   0x0002
 
#define BGWORKER_CLASS_PARALLEL   0x0010
 
#define BGW_DEFAULT_RESTART_INTERVAL   60
 
#define BGW_NEVER_RESTART   -1
 
#define BGW_MAXLEN   96
 
#define BGW_EXTRALEN   128
 
#define BGWORKER_BYPASS_ALLOWCONN   0x0001
 
#define BGWORKER_BYPASS_ROLELOGINCHECK   0x0002
 

Typedefs

typedef void(* bgworker_main_type) (Datum main_arg)
 
typedef struct BackgroundWorker BackgroundWorker
 
typedef enum BgwHandleStatus BgwHandleStatus
 
typedef struct BackgroundWorkerHandle BackgroundWorkerHandle
 

Enumerations

enum  BgWorkerStartTime { BgWorkerStart_PostmasterStart , BgWorkerStart_ConsistentState , BgWorkerStart_RecoveryFinished }
 
enum  BgwHandleStatus { BGWH_STARTED , BGWH_NOT_YET_STARTED , BGWH_STOPPED , BGWH_POSTMASTER_DIED }
 

Functions

void RegisterBackgroundWorker (BackgroundWorker *worker)
 
bool RegisterDynamicBackgroundWorker (BackgroundWorker *worker, BackgroundWorkerHandle **handle)
 
BgwHandleStatus GetBackgroundWorkerPid (BackgroundWorkerHandle *handle, pid_t *pidp)
 
BgwHandleStatus WaitForBackgroundWorkerStartup (BackgroundWorkerHandle *handle, pid_t *pidp)
 
BgwHandleStatus WaitForBackgroundWorkerShutdown (BackgroundWorkerHandle *)
 
const char * GetBackgroundWorkerTypeByPid (pid_t pid)
 
void TerminateBackgroundWorker (BackgroundWorkerHandle *handle)
 
void BackgroundWorkerInitializeConnection (const char *dbname, const char *username, uint32 flags)
 
void BackgroundWorkerInitializeConnectionByOid (Oid dboid, Oid useroid, uint32 flags)
 
void BackgroundWorkerBlockSignals (void)
 
void BackgroundWorkerUnblockSignals (void)
 

Variables

PGDLLIMPORT BackgroundWorkerMyBgworkerEntry
 

Macro Definition Documentation

◆ BGW_DEFAULT_RESTART_INTERVAL

#define BGW_DEFAULT_RESTART_INTERVAL   60

Definition at line 84 of file bgworker.h.

◆ BGW_EXTRALEN

#define BGW_EXTRALEN   128

Definition at line 87 of file bgworker.h.

◆ BGW_MAXLEN

#define BGW_MAXLEN   96

Definition at line 86 of file bgworker.h.

◆ BGW_NEVER_RESTART

#define BGW_NEVER_RESTART   -1

Definition at line 85 of file bgworker.h.

◆ BGWORKER_BACKEND_DATABASE_CONNECTION

#define BGWORKER_BACKEND_DATABASE_CONNECTION   0x0002

Definition at line 60 of file bgworker.h.

◆ BGWORKER_BYPASS_ALLOWCONN

#define BGWORKER_BYPASS_ALLOWCONN   0x0001

Definition at line 156 of file bgworker.h.

◆ BGWORKER_BYPASS_ROLELOGINCHECK

#define BGWORKER_BYPASS_ROLELOGINCHECK   0x0002

Definition at line 157 of file bgworker.h.

◆ BGWORKER_CLASS_PARALLEL

#define BGWORKER_CLASS_PARALLEL   0x0010

Definition at line 68 of file bgworker.h.

◆ BGWORKER_SHMEM_ACCESS

#define BGWORKER_SHMEM_ACCESS   0x0001

Definition at line 53 of file bgworker.h.

Typedef Documentation

◆ BackgroundWorker

◆ BackgroundWorkerHandle

Definition at line 72 of file bgworker.h.

◆ BgwHandleStatus

◆ bgworker_main_type

typedef void(* bgworker_main_type) (Datum main_arg)

Definition at line 72 of file bgworker.h.

Enumeration Type Documentation

◆ BgwHandleStatus

Enumerator
BGWH_STARTED 
BGWH_NOT_YET_STARTED 
BGWH_STOPPED 
BGWH_POSTMASTER_DIED 

Definition at line 103 of file bgworker.h.

104 {
105  BGWH_STARTED, /* worker is running */
106  BGWH_NOT_YET_STARTED, /* worker hasn't been started yet */
107  BGWH_STOPPED, /* worker has exited */
108  BGWH_POSTMASTER_DIED, /* postmaster died; worker status unclear */
BgwHandleStatus
Definition: bgworker.h:104
@ BGWH_POSTMASTER_DIED
Definition: bgworker.h:108
@ BGWH_STARTED
Definition: bgworker.h:105
@ BGWH_NOT_YET_STARTED
Definition: bgworker.h:106
@ BGWH_STOPPED
Definition: bgworker.h:107

◆ BgWorkerStartTime

Enumerator
BgWorkerStart_PostmasterStart 
BgWorkerStart_ConsistentState 
BgWorkerStart_RecoveryFinished 

Definition at line 77 of file bgworker.h.

78 {
BgWorkerStartTime
Definition: bgworker.h:78
@ BgWorkerStart_RecoveryFinished
Definition: bgworker.h:81
@ BgWorkerStart_ConsistentState
Definition: bgworker.h:80
@ BgWorkerStart_PostmasterStart
Definition: bgworker.h:79

Function Documentation

◆ BackgroundWorkerBlockSignals()

void BackgroundWorkerBlockSignals ( void  )

Definition at line 5595 of file postmaster.c.

5596 {
5597  sigprocmask(SIG_SETMASK, &BlockSig, NULL);
5598 }
sigset_t BlockSig
Definition: pqsignal.c:23

References BlockSig.

◆ BackgroundWorkerInitializeConnection()

void BackgroundWorkerInitializeConnection ( const char *  dbname,
const char *  username,
uint32  flags 
)

Definition at line 5527 of file postmaster.c.

5528 {
5530  bits32 init_flags = 0; /* never honor session_preload_libraries */
5531 
5532  /* ignore datallowconn? */
5533  if (flags & BGWORKER_BYPASS_ALLOWCONN)
5534  init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
5535  /* ignore rolcanlogin? */
5536  if (flags & BGWORKER_BYPASS_ROLELOGINCHECK)
5537  init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
5538 
5539  /* XXX is this the right errcode? */
5541  ereport(FATAL,
5542  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
5543  errmsg("database connection requirement not indicated during registration")));
5544 
5545  InitPostgres(dbname, InvalidOid, /* database to connect to */
5546  username, InvalidOid, /* role to connect as */
5547  init_flags,
5548  NULL); /* no out_dbname */
5549 
5550  /* it had better not gotten out of "init" mode yet */
5551  if (!IsInitProcessingMode())
5552  ereport(ERROR,
5553  (errmsg("invalid processing mode in background worker")));
5555 }
#define BGWORKER_BYPASS_ROLELOGINCHECK
Definition: bgworker.h:157
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:60
#define BGWORKER_BYPASS_ALLOWCONN
Definition: bgworker.h:156
uint32 bits32
Definition: c.h:504
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define FATAL
Definition: elog.h:41
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
@ NormalProcessing
Definition: miscadmin.h:412
#define IsInitProcessingMode()
Definition: miscadmin.h:418
#define SetProcessingMode(mode)
Definition: miscadmin.h:423
#define INIT_PG_OVERRIDE_ROLE_LOGIN
Definition: miscadmin.h:472
#define INIT_PG_OVERRIDE_ALLOW_CONNS
Definition: miscadmin.h:471
const char * username
Definition: pgbench.c:296
#define InvalidOid
Definition: postgres_ext.h:36
void InitPostgres(const char *in_dbname, Oid dboid, const char *username, Oid useroid, bits32 flags, char *out_dbname)
Definition: postinit.c:720
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:194
char * dbname
Definition: streamutil.c:51

References BackgroundWorker::bgw_flags, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_BYPASS_ALLOWCONN, BGWORKER_BYPASS_ROLELOGINCHECK, dbname, ereport, errcode(), errmsg(), ERROR, FATAL, INIT_PG_OVERRIDE_ALLOW_CONNS, INIT_PG_OVERRIDE_ROLE_LOGIN, InitPostgres(), InvalidOid, IsInitProcessingMode, MyBgworkerEntry, NormalProcessing, SetProcessingMode, and username.

Referenced by ApplyLauncherMain(), and worker_spi_main().

◆ BackgroundWorkerInitializeConnectionByOid()

void BackgroundWorkerInitializeConnectionByOid ( Oid  dboid,
Oid  useroid,
uint32  flags 
)

Definition at line 5561 of file postmaster.c.

5562 {
5564  bits32 init_flags = 0; /* never honor session_preload_libraries */
5565 
5566  /* ignore datallowconn? */
5567  if (flags & BGWORKER_BYPASS_ALLOWCONN)
5568  init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
5569  /* ignore rolcanlogin? */
5570  if (flags & BGWORKER_BYPASS_ROLELOGINCHECK)
5571  init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
5572 
5573  /* XXX is this the right errcode? */
5575  ereport(FATAL,
5576  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
5577  errmsg("database connection requirement not indicated during registration")));
5578 
5579  InitPostgres(NULL, dboid, /* database to connect to */
5580  NULL, useroid, /* role to connect as */
5581  init_flags,
5582  NULL); /* no out_dbname */
5583 
5584  /* it had better not gotten out of "init" mode yet */
5585  if (!IsInitProcessingMode())
5586  ereport(ERROR,
5587  (errmsg("invalid processing mode in background worker")));
5589 }

References BackgroundWorker::bgw_flags, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_BYPASS_ALLOWCONN, BGWORKER_BYPASS_ROLELOGINCHECK, ereport, errcode(), errmsg(), ERROR, FATAL, INIT_PG_OVERRIDE_ALLOW_CONNS, INIT_PG_OVERRIDE_ROLE_LOGIN, InitPostgres(), IsInitProcessingMode, MyBgworkerEntry, NormalProcessing, and SetProcessingMode.

Referenced by autoprewarm_database_main(), InitializeLogRepWorker(), ParallelWorkerMain(), and worker_spi_main().

◆ BackgroundWorkerUnblockSignals()

void BackgroundWorkerUnblockSignals ( void  )

Definition at line 5601 of file postmaster.c.

5602 {
5603  sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
5604 }
sigset_t UnBlockSig
Definition: pqsignal.c:22

References UnBlockSig.

Referenced by ApplyLauncherMain(), autoprewarm_database_main(), autoprewarm_main(), BackgroundWorkerMain(), ParallelApplyWorkerMain(), ParallelWorkerMain(), SetupApplyOrSyncWorker(), test_shm_mq_main(), and worker_spi_main().

◆ GetBackgroundWorkerPid()

BgwHandleStatus GetBackgroundWorkerPid ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1073 of file bgworker.c.

1074 {
1075  BackgroundWorkerSlot *slot;
1076  pid_t pid;
1077 
1078  Assert(handle->slot < max_worker_processes);
1079  slot = &BackgroundWorkerData->slot[handle->slot];
1080 
1081  /*
1082  * We could probably arrange to synchronize access to data using memory
1083  * barriers only, but for now, let's just keep it simple and grab the
1084  * lock. It seems unlikely that there will be enough traffic here to
1085  * result in meaningful contention.
1086  */
1087  LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1088 
1089  /*
1090  * The generation number can't be concurrently changed while we hold the
1091  * lock. The pid, which is updated by the postmaster, can change at any
1092  * time, but we assume such changes are atomic. So the value we read
1093  * won't be garbage, but it might be out of date by the time the caller
1094  * examines it (but that's unavoidable anyway).
1095  *
1096  * The in_use flag could be in the process of changing from true to false,
1097  * but if it is already false then it can't change further.
1098  */
1099  if (handle->generation != slot->generation || !slot->in_use)
1100  pid = 0;
1101  else
1102  pid = slot->pid;
1103 
1104  /* All done. */
1105  LWLockRelease(BackgroundWorkerLock);
1106 
1107  if (pid == 0)
1108  return BGWH_STOPPED;
1109  else if (pid == InvalidPid)
1110  return BGWH_NOT_YET_STARTED;
1111  *pidp = pid;
1112  return BGWH_STARTED;
1113 }
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
int max_worker_processes
Definition: globals.c:140
Assert(fmt[strlen(fmt) - 1] !='\n')
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1195
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1808
@ LW_SHARED
Definition: lwlock.h:117
#define InvalidPid
Definition: miscadmin.h:32
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102

References Assert(), BackgroundWorkerData, BGWH_NOT_YET_STARTED, BGWH_STARTED, BGWH_STOPPED, BackgroundWorkerSlot::generation, BackgroundWorkerHandle::generation, BackgroundWorkerSlot::in_use, InvalidPid, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_worker_processes, BackgroundWorkerSlot::pid, BackgroundWorkerArray::slot, and BackgroundWorkerHandle::slot.

Referenced by check_worker_status(), shm_mq_counterparty_gone(), shm_mq_wait_internal(), WaitForBackgroundWorkerShutdown(), WaitForBackgroundWorkerStartup(), WaitForParallelWorkersToAttach(), WaitForParallelWorkersToFinish(), and WaitForReplicationWorkerAttach().

◆ GetBackgroundWorkerTypeByPid()

const char* GetBackgroundWorkerTypeByPid ( pid_t  pid)

Definition at line 1287 of file bgworker.c.

1288 {
1289  int slotno;
1290  bool found = false;
1291  static char result[BGW_MAXLEN];
1292 
1293  LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1294 
1295  for (slotno = 0; slotno < BackgroundWorkerData->total_slots; slotno++)
1296  {
1298 
1299  if (slot->pid > 0 && slot->pid == pid)
1300  {
1301  strcpy(result, slot->worker.bgw_type);
1302  found = true;
1303  break;
1304  }
1305  }
1306 
1307  LWLockRelease(BackgroundWorkerLock);
1308 
1309  if (!found)
1310  return NULL;
1311 
1312  return result;
1313 }
#define BGW_MAXLEN
Definition: bgworker.h:86
BackgroundWorker worker
Definition: bgworker.c:83
char bgw_type[BGW_MAXLEN]
Definition: bgworker.h:92

References BackgroundWorkerData, BGW_MAXLEN, BackgroundWorker::bgw_type, LW_SHARED, LWLockAcquire(), LWLockRelease(), BackgroundWorkerSlot::pid, BackgroundWorkerArray::slot, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by pg_stat_get_activity().

◆ RegisterBackgroundWorker()

void RegisterBackgroundWorker ( BackgroundWorker worker)

Definition at line 853 of file bgworker.c.

854 {
855  RegisteredBgWorker *rw;
856  static int numworkers = 0;
857 
858  /*
859  * Static background workers can only be registered in the postmaster
860  * process.
861  */
863  {
864  /*
865  * In EXEC_BACKEND or single-user mode, we process
866  * shared_preload_libraries in backend processes too. We cannot
867  * register static background workers at that stage, but many
868  * libraries' _PG_init() functions don't distinguish whether they're
869  * being loaded in the postmaster or in a backend, they just check
870  * process_shared_preload_libraries_in_progress. It's a bit sloppy,
871  * but for historical reasons we tolerate it. In EXEC_BACKEND mode,
872  * the background workers should already have been registered when the
873  * library was loaded in postmaster.
874  */
876  return;
877  ereport(LOG,
878  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
879  errmsg("background worker \"%s\": must be registered in shared_preload_libraries",
880  worker->bgw_name)));
881  return;
882  }
883 
884  /*
885  * Cannot register static background workers after calling
886  * BackgroundWorkerShmemInit().
887  */
888  if (BackgroundWorkerData != NULL)
889  elog(ERROR, "cannot register background worker \"%s\" after shmem init",
890  worker->bgw_name);
891 
892  ereport(DEBUG1,
893  (errmsg_internal("registering background worker \"%s\"", worker->bgw_name)));
894 
895  if (!SanityCheckBackgroundWorker(worker, LOG))
896  return;
897 
898  if (worker->bgw_notify_pid != 0)
899  {
900  ereport(LOG,
901  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
902  errmsg("background worker \"%s\": only dynamic background workers can request notification",
903  worker->bgw_name)));
904  return;
905  }
906 
907  /*
908  * Enforce maximum number of workers. Note this is overly restrictive: we
909  * could allow more non-shmem-connected workers, because these don't count
910  * towards the MAX_BACKENDS limit elsewhere. For now, it doesn't seem
911  * important to relax this restriction.
912  */
913  if (++numworkers > max_worker_processes)
914  {
915  ereport(LOG,
916  (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
917  errmsg("too many background workers"),
918  errdetail_plural("Up to %d background worker can be registered with the current settings.",
919  "Up to %d background workers can be registered with the current settings.",
922  errhint("Consider increasing the configuration parameter max_worker_processes.")));
923  return;
924  }
925 
926  /*
927  * Copy the registration data into the registered workers list.
928  */
930  sizeof(RegisteredBgWorker),
932  if (rw == NULL)
933  {
934  ereport(LOG,
935  (errcode(ERRCODE_OUT_OF_MEMORY),
936  errmsg("out of memory")));
937  return;
938  }
939 
940  rw->rw_worker = *worker;
941  rw->rw_backend = NULL;
942  rw->rw_pid = 0;
943  rw->rw_child_slot = 0;
944  rw->rw_crashed_at = 0;
945  rw->rw_terminate = false;
946 
948 }
static bool SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
Definition: bgworker.c:640
slist_head BackgroundWorkerList
Definition: bgworker.c:43
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1156
int errdetail_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1294
int errhint(const char *fmt,...)
Definition: elog.c:1316
#define LOG
Definition: elog.h:31
#define DEBUG1
Definition: elog.h:30
#define MCXT_ALLOC_NO_OOM
Definition: fe_memutils.h:17
bool IsUnderPostmaster
Definition: globals.c:115
bool IsPostmasterEnvironment
Definition: globals.c:114
static void slist_push_head(slist_head *head, slist_node *node)
Definition: ilist.h:1006
void * MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
Definition: mcxt.c:1137
MemoryContext PostmasterContext
Definition: mcxt.c:143
bool process_shared_preload_libraries_in_progress
Definition: miscinit.c:1771
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:91
pid_t bgw_notify_pid
Definition: bgworker.h:100
struct bkend * rw_backend
BackgroundWorker rw_worker

References BackgroundWorkerData, BackgroundWorkerList, BackgroundWorker::bgw_name, BackgroundWorker::bgw_notify_pid, DEBUG1, elog(), ereport, errcode(), errdetail_plural(), errhint(), errmsg(), errmsg_internal(), ERROR, IsPostmasterEnvironment, IsUnderPostmaster, LOG, max_worker_processes, MCXT_ALLOC_NO_OOM, MemoryContextAllocExtended(), PostmasterContext, process_shared_preload_libraries_in_progress, RegisteredBgWorker::rw_backend, RegisteredBgWorker::rw_child_slot, RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SanityCheckBackgroundWorker(), and slist_push_head().

Referenced by _PG_init(), ApplyLauncherRegister(), and apw_start_leader_worker().

◆ RegisterDynamicBackgroundWorker()

bool RegisterDynamicBackgroundWorker ( BackgroundWorker worker,
BackgroundWorkerHandle **  handle 
)

Definition at line 961 of file bgworker.c.

963 {
964  int slotno;
965  bool success = false;
966  bool parallel;
967  uint64 generation = 0;
968 
969  /*
970  * We can't register dynamic background workers from the postmaster. If
971  * this is a standalone backend, we're the only process and can't start
972  * any more. In a multi-process environment, it might be theoretically
973  * possible, but we don't currently support it due to locking
974  * considerations; see comments on the BackgroundWorkerSlot data
975  * structure.
976  */
977  if (!IsUnderPostmaster)
978  return false;
979 
980  if (!SanityCheckBackgroundWorker(worker, ERROR))
981  return false;
982 
983  parallel = (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0;
984 
985  LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
986 
987  /*
988  * If this is a parallel worker, check whether there are already too many
989  * parallel workers; if so, don't register another one. Our view of
990  * parallel_terminate_count may be slightly stale, but that doesn't really
991  * matter: we would have gotten the same result if we'd arrived here
992  * slightly earlier anyway. There's no help for it, either, since the
993  * postmaster must not take locks; a memory barrier wouldn't guarantee
994  * anything useful.
995  */
999  {
1003  LWLockRelease(BackgroundWorkerLock);
1004  return false;
1005  }
1006 
1007  /*
1008  * Look for an unused slot. If we find one, grab it.
1009  */
1010  for (slotno = 0; slotno < BackgroundWorkerData->total_slots; ++slotno)
1011  {
1013 
1014  if (!slot->in_use)
1015  {
1016  memcpy(&slot->worker, worker, sizeof(BackgroundWorker));
1017  slot->pid = InvalidPid; /* indicates not started yet */
1018  slot->generation++;
1019  slot->terminate = false;
1020  generation = slot->generation;
1021  if (parallel)
1023 
1024  /*
1025  * Make sure postmaster doesn't see the slot as in use before it
1026  * sees the new contents.
1027  */
1028  pg_write_barrier();
1029 
1030  slot->in_use = true;
1031  success = true;
1032  break;
1033  }
1034  }
1035 
1036  LWLockRelease(BackgroundWorkerLock);
1037 
1038  /* If we found a slot, tell the postmaster to notice the change. */
1039  if (success)
1041 
1042  /*
1043  * If we found a slot and the user has provided a handle, initialize it.
1044  */
1045  if (success && handle)
1046  {
1047  *handle = palloc(sizeof(BackgroundWorkerHandle));
1048  (*handle)->slot = slotno;
1049  (*handle)->generation = generation;
1050  }
1051 
1052  return success;
1053 }
#define pg_write_barrier()
Definition: atomics.h:154
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:68
#define MAX_PARALLEL_WORKER_LIMIT
int max_parallel_workers
Definition: globals.c:141
static bool success
Definition: initdb.c:184
@ LW_EXCLUSIVE
Definition: lwlock.h:116
void * palloc(Size size)
Definition: mcxt.c:1226
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:181
@ PMSIGNAL_BACKGROUND_WORKER_CHANGE
Definition: pmsignal.h:40
uint32 parallel_terminate_count
Definition: bgworker.c:101
uint32 parallel_register_count
Definition: bgworker.c:100

References Assert(), BackgroundWorkerData, BackgroundWorker::bgw_flags, BGWORKER_CLASS_PARALLEL, ERROR, BackgroundWorkerSlot::generation, BackgroundWorkerSlot::in_use, InvalidPid, IsUnderPostmaster, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAX_PARALLEL_WORKER_LIMIT, max_parallel_workers, palloc(), BackgroundWorkerArray::parallel_register_count, BackgroundWorkerArray::parallel_terminate_count, pg_write_barrier, BackgroundWorkerSlot::pid, PMSIGNAL_BACKGROUND_WORKER_CHANGE, SanityCheckBackgroundWorker(), SendPostmasterSignal(), BackgroundWorkerArray::slot, success, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by apw_start_database_worker(), apw_start_leader_worker(), LaunchParallelWorkers(), logicalrep_worker_launch(), setup_background_workers(), and worker_spi_launch().

◆ TerminateBackgroundWorker()

void TerminateBackgroundWorker ( BackgroundWorkerHandle handle)

Definition at line 1212 of file bgworker.c.

1213 {
1214  BackgroundWorkerSlot *slot;
1215  bool signal_postmaster = false;
1216 
1217  Assert(handle->slot < max_worker_processes);
1218  slot = &BackgroundWorkerData->slot[handle->slot];
1219 
1220  /* Set terminate flag in shared memory, unless slot has been reused. */
1221  LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1222  if (handle->generation == slot->generation)
1223  {
1224  slot->terminate = true;
1225  signal_postmaster = true;
1226  }
1227  LWLockRelease(BackgroundWorkerLock);
1228 
1229  /* Make sure the postmaster notices the change to shared memory. */
1230  if (signal_postmaster)
1232 }

References Assert(), BackgroundWorkerData, BackgroundWorkerSlot::generation, BackgroundWorkerHandle::generation, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), max_worker_processes, PMSIGNAL_BACKGROUND_WORKER_CHANGE, SendPostmasterSignal(), BackgroundWorkerArray::slot, BackgroundWorkerHandle::slot, and BackgroundWorkerSlot::terminate.

Referenced by cleanup_background_workers(), and DestroyParallelContext().

◆ WaitForBackgroundWorkerShutdown()

BgwHandleStatus WaitForBackgroundWorkerShutdown ( BackgroundWorkerHandle handle)

Definition at line 1173 of file bgworker.c.

1174 {
1175  BgwHandleStatus status;
1176  int rc;
1177 
1178  for (;;)
1179  {
1180  pid_t pid;
1181 
1183 
1184  status = GetBackgroundWorkerPid(handle, &pid);
1185  if (status == BGWH_STOPPED)
1186  break;
1187 
1188  rc = WaitLatch(MyLatch,
1190  WAIT_EVENT_BGWORKER_SHUTDOWN);
1191 
1192  if (rc & WL_POSTMASTER_DEATH)
1193  {
1194  status = BGWH_POSTMASTER_DIED;
1195  break;
1196  }
1197 
1199  }
1200 
1201  return status;
1202 }
BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1073
struct Latch * MyLatch
Definition: globals.c:58
void ResetLatch(Latch *latch)
Definition: latch.c:725
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:518
#define WL_LATCH_SET
Definition: latch.h:127
#define WL_POSTMASTER_DEATH
Definition: latch.h:131
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121

References BGWH_POSTMASTER_DIED, BGWH_STOPPED, CHECK_FOR_INTERRUPTS, GetBackgroundWorkerPid(), MyLatch, ResetLatch(), WaitLatch(), WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by apw_start_database_worker(), and WaitForParallelWorkersToExit().

◆ WaitForBackgroundWorkerStartup()

BgwHandleStatus WaitForBackgroundWorkerStartup ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1128 of file bgworker.c.

1129 {
1130  BgwHandleStatus status;
1131  int rc;
1132 
1133  for (;;)
1134  {
1135  pid_t pid;
1136 
1138 
1139  status = GetBackgroundWorkerPid(handle, &pid);
1140  if (status == BGWH_STARTED)
1141  *pidp = pid;
1142  if (status != BGWH_NOT_YET_STARTED)
1143  break;
1144 
1145  rc = WaitLatch(MyLatch,
1147  WAIT_EVENT_BGWORKER_STARTUP);
1148 
1149  if (rc & WL_POSTMASTER_DEATH)
1150  {
1151  status = BGWH_POSTMASTER_DIED;
1152  break;
1153  }
1154 
1156  }
1157 
1158  return status;
1159 }

References BGWH_NOT_YET_STARTED, BGWH_POSTMASTER_DIED, BGWH_STARTED, CHECK_FOR_INTERRUPTS, GetBackgroundWorkerPid(), MyLatch, ResetLatch(), WaitLatch(), WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by apw_start_leader_worker(), and worker_spi_launch().

Variable Documentation

◆ MyBgworkerEntry