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bgworker.c File Reference
#include "postgres.h"
#include <unistd.h>
#include "libpq/pqsignal.h"
#include "access/parallel.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/atomics.h"
#include "postmaster/bgworker_internals.h"
#include "postmaster/postmaster.h"
#include "replication/logicallauncher.h"
#include "replication/logicalworker.h"
#include "storage/dsm.h"
#include "storage/ipc.h"
#include "storage/latch.h"
#include "storage/lwlock.h"
#include "storage/pg_shmem.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/procsignal.h"
#include "storage/shmem.h"
#include "tcop/tcopprot.h"
#include "utils/ascii.h"
#include "utils/ps_status.h"
#include "utils/timeout.h"
Include dependency graph for bgworker.c:

Go to the source code of this file.

Data Structures

struct  BackgroundWorkerSlot
 
struct  BackgroundWorkerArray
 
struct  BackgroundWorkerHandle
 

Typedefs

typedef struct BackgroundWorkerSlot BackgroundWorkerSlot
 
typedef struct
BackgroundWorkerArray 
BackgroundWorkerArray
 

Functions

static bgworker_main_type LookupBackgroundWorkerFunction (const char *libraryname, const char *funcname)
 
Size BackgroundWorkerShmemSize (void)
 
void BackgroundWorkerShmemInit (void)
 
static RegisteredBgWorkerFindRegisteredWorkerBySlotNumber (int slotno)
 
void BackgroundWorkerStateChange (void)
 
void ForgetBackgroundWorker (slist_mutable_iter *cur)
 
void ReportBackgroundWorkerPID (RegisteredBgWorker *rw)
 
void ReportBackgroundWorkerExit (slist_mutable_iter *cur)
 
void BackgroundWorkerStopNotifications (pid_t pid)
 
void ResetBackgroundWorkerCrashTimes (void)
 
static bool SanityCheckBackgroundWorker (BackgroundWorker *worker, int elevel)
 
static void bgworker_quickdie (SIGNAL_ARGS)
 
static void bgworker_die (SIGNAL_ARGS)
 
static void bgworker_sigusr1_handler (SIGNAL_ARGS)
 
void StartBackgroundWorker (void)
 
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 *handle)
 
void TerminateBackgroundWorker (BackgroundWorkerHandle *handle)
 

Variables

slist_head BackgroundWorkerList = SLIST_STATIC_INIT(BackgroundWorkerList)
 
static BackgroundWorkerArrayBackgroundWorkerData
 
struct {
   const char *   fn_name
 
   bgworker_main_type   fn_addr
 
InternalBGWorkers []
 

Typedef Documentation

Function Documentation

void BackgroundWorkerShmemInit ( void  )

Definition at line 159 of file bgworker.c.

References Assert, BackgroundWorkerShmemSize(), BackgroundWorker::bgw_notify_pid, slist_iter::cur, BackgroundWorkerSlot::generation, BackgroundWorkerSlot::in_use, InvalidPid, IsUnderPostmaster, max_worker_processes, BackgroundWorkerArray::parallel_register_count, BackgroundWorkerArray::parallel_terminate_count, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, ShmemInitStruct(), slist_container, slist_foreach, BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by CreateSharedMemoryAndSemaphores().

160 {
161  bool found;
162 
163  BackgroundWorkerData = ShmemInitStruct("Background Worker Data",
165  &found);
166  if (!IsUnderPostmaster)
167  {
168  slist_iter siter;
169  int slotno = 0;
170 
174 
175  /*
176  * Copy contents of worker list into shared memory. Record the shared
177  * memory slot assigned to each worker. This ensures a 1-to-1
178  * correspondence between the postmaster's private list and the array
179  * in shared memory.
180  */
182  {
184  RegisteredBgWorker *rw;
185 
186  rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur);
187  Assert(slotno < max_worker_processes);
188  slot->in_use = true;
189  slot->terminate = false;
190  slot->pid = InvalidPid;
191  slot->generation = 0;
192  rw->rw_shmem_slot = slotno;
193  rw->rw_worker.bgw_notify_pid = 0; /* might be reinit after crash */
194  memcpy(&slot->worker, &rw->rw_worker, sizeof(BackgroundWorker));
195  ++slotno;
196  }
197 
198  /*
199  * Mark any remaining slots as not in use.
200  */
201  while (slotno < max_worker_processes)
202  {
204 
205  slot->in_use = false;
206  ++slotno;
207  }
208  }
209  else
210  Assert(found);
211 }
slist_node * cur
Definition: ilist.h:226
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:143
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:372
slist_head BackgroundWorkerList
Definition: bgworker.c:43
uint32 parallel_register_count
Definition: bgworker.c:100
bool IsUnderPostmaster
Definition: globals.c:100
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define Assert(condition)
Definition: c.h:675
BackgroundWorker worker
Definition: bgworker.c:83
#define slist_foreach(iter, lhead)
Definition: ilist.h:700
uint32 parallel_terminate_count
Definition: bgworker.c:101
pid_t bgw_notify_pid
Definition: bgworker.h:98
int max_worker_processes
Definition: globals.c:124
BackgroundWorker rw_worker
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
#define InvalidPid
Definition: miscadmin.h:31
Size BackgroundWorkerShmemSize ( void  )

Definition at line 143 of file bgworker.c.

References add_size(), max_worker_processes, mul_size(), and offsetof.

Referenced by BackgroundWorkerShmemInit(), and CreateSharedMemoryAndSemaphores().

144 {
145  Size size;
146 
147  /* Array of workers is variably sized. */
148  size = offsetof(BackgroundWorkerArray, slot);
150  sizeof(BackgroundWorkerSlot)));
151 
152  return size;
153 }
Size mul_size(Size s1, Size s2)
Definition: shmem.c:492
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
size_t Size
Definition: c.h:356
int max_worker_processes
Definition: globals.c:124
#define offsetof(type, field)
Definition: c.h:555
void BackgroundWorkerStateChange ( void  )

Definition at line 241 of file bgworker.c.

References ascii_safe_strlcpy(), BackgroundWorker::bgw_extra, BGW_EXTRALEN, BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BGW_MAXLEN, BackgroundWorker::bgw_name, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BGWORKER_CLASS_PARALLEL, DEBUG1, elog, ereport, errcode(), errmsg(), FindRegisteredWorkerBySlotNumber(), BackgroundWorkerSlot::in_use, LOG, malloc, max_worker_processes, NULL, BackgroundWorkerArray::parallel_terminate_count, pg_memory_barrier, pg_read_barrier, BackgroundWorkerSlot::pid, PostmasterMarkPIDForWorkerNotify(), ReportBackgroundWorkerPID(), RegisteredBgWorker::rw_backend, RegisteredBgWorker::rw_child_slot, RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SIGUSR1, slist_push_head(), BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by sigusr1_handler().

242 {
243  int slotno;
244 
245  /*
246  * The total number of slots stored in shared memory should match our
247  * notion of max_worker_processes. If it does not, something is very
248  * wrong. Further down, we always refer to this value as
249  * max_worker_processes, in case shared memory gets corrupted while we're
250  * looping.
251  */
253  {
254  elog(LOG,
255  "inconsistent background worker state (max_worker_processes=%d, total_slots=%d",
258  return;
259  }
260 
261  /*
262  * Iterate through slots, looking for newly-registered workers or workers
263  * who must die.
264  */
265  for (slotno = 0; slotno < max_worker_processes; ++slotno)
266  {
268  RegisteredBgWorker *rw;
269 
270  if (!slot->in_use)
271  continue;
272 
273  /*
274  * Make sure we don't see the in_use flag before the updated slot
275  * contents.
276  */
277  pg_read_barrier();
278 
279  /* See whether we already know about this worker. */
281  if (rw != NULL)
282  {
283  /*
284  * In general, the worker data can't change after it's initially
285  * registered. However, someone can set the terminate flag.
286  */
287  if (slot->terminate && !rw->rw_terminate)
288  {
289  rw->rw_terminate = true;
290  if (rw->rw_pid != 0)
291  kill(rw->rw_pid, SIGTERM);
292  else
293  {
294  /* Report never-started, now-terminated worker as dead. */
296  }
297  }
298  continue;
299  }
300 
301  /*
302  * If the worker is marked for termination, we don't need to add it to
303  * the registered workers list; we can just free the slot. However, if
304  * bgw_notify_pid is set, the process that registered the worker may
305  * need to know that we've processed the terminate request, so be sure
306  * to signal it.
307  */
308  if (slot->terminate)
309  {
310  int notify_pid;
311 
312  /*
313  * We need a memory barrier here to make sure that the load of
314  * bgw_notify_pid and the update of parallel_terminate_count
315  * complete before the store to in_use.
316  */
317  notify_pid = slot->worker.bgw_notify_pid;
318  if ((slot->worker.bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
321  slot->pid = 0;
322  slot->in_use = false;
323  if (notify_pid != 0)
324  kill(notify_pid, SIGUSR1);
325 
326  continue;
327  }
328 
329  /*
330  * Copy the registration data into the registered workers list.
331  */
332  rw = malloc(sizeof(RegisteredBgWorker));
333  if (rw == NULL)
334  {
335  ereport(LOG,
336  (errcode(ERRCODE_OUT_OF_MEMORY),
337  errmsg("out of memory")));
338  return;
339  }
340 
341  /*
342  * Copy strings in a paranoid way. If shared memory is corrupted, the
343  * source data might not even be NUL-terminated.
344  */
346  slot->worker.bgw_name, BGW_MAXLEN);
351 
352  /*
353  * Copy various fixed-size fields.
354  *
355  * flags, start_time, and restart_time are examined by the postmaster,
356  * but nothing too bad will happen if they are corrupted. The
357  * remaining fields will only be examined by the child process. It
358  * might crash, but we won't.
359  */
360  rw->rw_worker.bgw_flags = slot->worker.bgw_flags;
364  memcpy(rw->rw_worker.bgw_extra, slot->worker.bgw_extra, BGW_EXTRALEN);
365 
366  /*
367  * Copy the PID to be notified about state changes, but only if the
368  * postmaster knows about a backend with that PID. It isn't an error
369  * if the postmaster doesn't know about the PID, because the backend
370  * that requested the worker could have died (or been killed) just
371  * after doing so. Nonetheless, at least until we get some experience
372  * with how this plays out in the wild, log a message at a relative
373  * high debug level.
374  */
377  {
378  elog(DEBUG1, "worker notification PID %lu is not valid",
379  (long) rw->rw_worker.bgw_notify_pid);
380  rw->rw_worker.bgw_notify_pid = 0;
381  }
382 
383  /* Initialize postmaster bookkeeping. */
384  rw->rw_backend = NULL;
385  rw->rw_pid = 0;
386  rw->rw_child_slot = 0;
387  rw->rw_crashed_at = 0;
388  rw->rw_shmem_slot = slotno;
389  rw->rw_terminate = false;
390 
391  /* Log it! */
392  ereport(DEBUG1,
393  (errmsg("registering background worker \"%s\"",
394  rw->rw_worker.bgw_name)));
395 
397  }
398 }
char bgw_extra[BGW_EXTRALEN]
Definition: bgworker.h:97
struct bkend * rw_backend
#define SIGUSR1
Definition: win32.h:202
#define DEBUG1
Definition: elog.h:25
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
static void slist_push_head(slist_head *head, slist_node *node)
Definition: ilist.h:574
int bgw_restart_time
Definition: bgworker.h:93
int errcode(int sqlerrcode)
Definition: elog.c:575
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:67
void ascii_safe_strlcpy(char *dest, const char *src, size_t destsiz)
Definition: ascii.c:173
#define LOG
Definition: elog.h:26
char bgw_function_name[BGW_MAXLEN]
Definition: bgworker.h:95
#define malloc(a)
Definition: header.h:50
Datum bgw_main_arg
Definition: bgworker.h:96
void ReportBackgroundWorkerPID(RegisteredBgWorker *rw)
Definition: bgworker.c:438
bool PostmasterMarkPIDForWorkerNotify(int pid)
Definition: postmaster.c:5854
slist_head BackgroundWorkerList
Definition: bgworker.c:43
#define ereport(elevel, rest)
Definition: elog.h:122
static RegisteredBgWorker * FindRegisteredWorkerBySlotNumber(int slotno)
Definition: bgworker.c:218
#define pg_memory_barrier()
Definition: atomics.h:148
#define NULL
Definition: c.h:229
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
BackgroundWorker worker
Definition: bgworker.c:83
#define pg_read_barrier()
Definition: atomics.h:161
#define BGW_MAXLEN
Definition: bgworker.h:85
BgWorkerStartTime bgw_start_time
Definition: bgworker.h:92
int errmsg(const char *fmt,...)
Definition: elog.c:797
uint32 parallel_terminate_count
Definition: bgworker.c:101
pid_t bgw_notify_pid
Definition: bgworker.h:98
int max_worker_processes
Definition: globals.c:124
#define elog
Definition: elog.h:219
BackgroundWorker rw_worker
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
char bgw_library_name[BGW_MAXLEN]
Definition: bgworker.h:94
#define BGW_EXTRALEN
Definition: bgworker.h:86
void BackgroundWorkerStopNotifications ( pid_t  pid)

Definition at line 491 of file bgworker.c.

References BackgroundWorker::bgw_notify_pid, slist_iter::cur, RegisteredBgWorker::rw_worker, slist_container, and slist_foreach.

Referenced by CleanupBackend(), and CleanupBackgroundWorker().

492 {
493  slist_iter siter;
494 
496  {
497  RegisteredBgWorker *rw;
498 
499  rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur);
500  if (rw->rw_worker.bgw_notify_pid == pid)
501  rw->rw_worker.bgw_notify_pid = 0;
502  }
503 }
slist_node * cur
Definition: ilist.h:226
slist_head BackgroundWorkerList
Definition: bgworker.c:43
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define slist_foreach(iter, lhead)
Definition: ilist.h:700
pid_t bgw_notify_pid
Definition: bgworker.h:98
BackgroundWorker rw_worker
static void bgworker_die ( SIGNAL_ARGS  )
static

Definition at line 667 of file bgworker.c.

References BackgroundWorker::bgw_name, BlockSig, ereport, errcode(), errmsg(), FATAL, MyBgworkerEntry, and PG_SETMASK.

Referenced by StartBackgroundWorker().

668 {
670 
671  ereport(FATAL,
672  (errcode(ERRCODE_ADMIN_SHUTDOWN),
673  errmsg("terminating background worker \"%s\" due to administrator command",
675 }
int errcode(int sqlerrcode)
Definition: elog.c:575
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:189
#define PG_SETMASK(mask)
Definition: pqsignal.h:19
#define FATAL
Definition: elog.h:52
#define ereport(elevel, rest)
Definition: elog.h:122
sigset_t BlockSig
Definition: pqsignal.c:22
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
int errmsg(const char *fmt,...)
Definition: elog.c:797
static void bgworker_quickdie ( SIGNAL_ARGS  )
static

Definition at line 637 of file bgworker.c.

References BlockSig, on_exit_reset(), PG_SETMASK, and SIGQUIT.

Referenced by StartBackgroundWorker().

638 {
639  sigaddset(&BlockSig, SIGQUIT); /* prevent nested calls */
641 
642  /*
643  * We DO NOT want to run proc_exit() callbacks -- we're here because
644  * shared memory may be corrupted, so we don't want to try to clean up our
645  * transaction. Just nail the windows shut and get out of town. Now that
646  * there's an atexit callback to prevent third-party code from breaking
647  * things by calling exit() directly, we have to reset the callbacks
648  * explicitly to make this work as intended.
649  */
650  on_exit_reset();
651 
652  /*
653  * Note we do exit(2) not exit(0). This is to force the postmaster into a
654  * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
655  * backend. This is necessary precisely because we don't clean up our
656  * shared memory state. (The "dead man switch" mechanism in pmsignal.c
657  * should ensure the postmaster sees this as a crash, too, but no harm in
658  * being doubly sure.)
659  */
660  exit(2);
661 }
#define SIGQUIT
Definition: win32.h:189
#define PG_SETMASK(mask)
Definition: pqsignal.h:19
void on_exit_reset(void)
Definition: ipc.c:396
sigset_t BlockSig
Definition: pqsignal.c:22
static void bgworker_sigusr1_handler ( SIGNAL_ARGS  )
static

Definition at line 684 of file bgworker.c.

References latch_sigusr1_handler().

Referenced by StartBackgroundWorker().

685 {
686  int save_errno = errno;
687 
689 
690  errno = save_errno;
691 }
void latch_sigusr1_handler(void)
Definition: latch.c:1467
static RegisteredBgWorker* FindRegisteredWorkerBySlotNumber ( int  slotno)
static

Definition at line 218 of file bgworker.c.

References slist_iter::cur, NULL, RegisteredBgWorker::rw_shmem_slot, slist_container, and slist_foreach.

Referenced by BackgroundWorkerStateChange().

219 {
220  slist_iter siter;
221 
223  {
224  RegisteredBgWorker *rw;
225 
226  rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur);
227  if (rw->rw_shmem_slot == slotno)
228  return rw;
229  }
230 
231  return NULL;
232 }
slist_node * cur
Definition: ilist.h:226
slist_head BackgroundWorkerList
Definition: bgworker.c:43
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define NULL
Definition: c.h:229
#define slist_foreach(iter, lhead)
Definition: ilist.h:700
void ForgetBackgroundWorker ( slist_mutable_iter cur)

Definition at line 410 of file bgworker.c.

References Assert, BackgroundWorker::bgw_flags, BackgroundWorker::bgw_name, BGWORKER_CLASS_PARALLEL, slist_mutable_iter::cur, DEBUG1, ereport, errmsg(), free, BackgroundWorkerSlot::in_use, max_worker_processes, BackgroundWorkerArray::parallel_terminate_count, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, slist_container, slist_delete_current(), and BackgroundWorkerArray::slot.

Referenced by DetermineSleepTime(), maybe_start_bgworkers(), ReportBackgroundWorkerExit(), and ResetBackgroundWorkerCrashTimes().

411 {
412  RegisteredBgWorker *rw;
413  BackgroundWorkerSlot *slot;
414 
415  rw = slist_container(RegisteredBgWorker, rw_lnode, cur->cur);
416 
421 
422  slot->in_use = false;
423 
424  ereport(DEBUG1,
425  (errmsg("unregistering background worker \"%s\"",
426  rw->rw_worker.bgw_name)));
427 
429  free(rw);
430 }
#define DEBUG1
Definition: elog.h:25
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
slist_node * cur
Definition: ilist.h:241
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:67
#define ereport(elevel, rest)
Definition: elog.h:122
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define free(a)
Definition: header.h:65
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
#define Assert(condition)
Definition: c.h:675
int errmsg(const char *fmt,...)
Definition: elog.c:797
uint32 parallel_terminate_count
Definition: bgworker.c:101
int max_worker_processes
Definition: globals.c:124
static void slist_delete_current(slist_mutable_iter *iter)
Definition: ilist.h:652
BackgroundWorker rw_worker
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
BgwHandleStatus GetBackgroundWorkerPid ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1041 of file bgworker.c.

References Assert, BGWH_NOT_YET_STARTED, BGWH_STARTED, BGWH_STOPPED, BackgroundWorkerSlot::generation, BackgroundWorkerHandle::generation, 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(), and WaitForReplicationWorkerAttach().

1042 {
1043  BackgroundWorkerSlot *slot;
1044  pid_t pid;
1045 
1046  Assert(handle->slot < max_worker_processes);
1047  slot = &BackgroundWorkerData->slot[handle->slot];
1048 
1049  /*
1050  * We could probably arrange to synchronize access to data using memory
1051  * barriers only, but for now, let's just keep it simple and grab the
1052  * lock. It seems unlikely that there will be enough traffic here to
1053  * result in meaningful contention.
1054  */
1055  LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1056 
1057  /*
1058  * The generation number can't be concurrently changed while we hold the
1059  * lock. The pid, which is updated by the postmaster, can change at any
1060  * time, but we assume such changes are atomic. So the value we read
1061  * won't be garbage, but it might be out of date by the time the caller
1062  * examines it (but that's unavoidable anyway).
1063  */
1064  if (handle->generation != slot->generation)
1065  pid = 0;
1066  else
1067  pid = slot->pid;
1068 
1069  /* All done. */
1070  LWLockRelease(BackgroundWorkerLock);
1071 
1072  if (pid == 0)
1073  return BGWH_STOPPED;
1074  else if (pid == InvalidPid)
1075  return BGWH_NOT_YET_STARTED;
1076  *pidp = pid;
1077  return BGWH_STARTED;
1078 }
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
#define Assert(condition)
Definition: c.h:675
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
int max_worker_processes
Definition: globals.c:124
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
#define InvalidPid
Definition: miscadmin.h:31
static bgworker_main_type LookupBackgroundWorkerFunction ( const char *  libraryname,
const char *  funcname 
)
static

Definition at line 1212 of file bgworker.c.

References elog, ERROR, fn_addr, fn_name, i, InternalBGWorkers, lengthof, load_external_function(), and NULL.

Referenced by StartBackgroundWorker().

1213 {
1214  /*
1215  * If the function is to be loaded from postgres itself, search the
1216  * InternalBGWorkers array.
1217  */
1218  if (strcmp(libraryname, "postgres") == 0)
1219  {
1220  int i;
1221 
1222  for (i = 0; i < lengthof(InternalBGWorkers); i++)
1223  {
1224  if (strcmp(InternalBGWorkers[i].fn_name, funcname) == 0)
1225  return InternalBGWorkers[i].fn_addr;
1226  }
1227 
1228  /* We can only reach this by programming error. */
1229  elog(ERROR, "internal function \"%s\" not found", funcname);
1230  }
1231 
1232  /* Otherwise load from external library. */
1233  return (bgworker_main_type)
1234  load_external_function(libraryname, funcname, true, NULL);
1235 }
#define lengthof(array)
Definition: c.h:562
const char * fn_name
Definition: bgworker.c:119
static const struct @23 InternalBGWorkers[]
#define ERROR
Definition: elog.h:43
void(* bgworker_main_type)(Datum main_arg)
Definition: bgworker.h:71
PGFunction load_external_function(const char *filename, const char *funcname, bool signalNotFound, void **filehandle)
Definition: dfmgr.c:94
#define NULL
Definition: c.h:229
bgworker_main_type fn_addr
Definition: bgworker.c:120
int i
#define elog
Definition: elog.h:219
void RegisterBackgroundWorker ( BackgroundWorker worker)

Definition at line 849 of file bgworker.c.

References BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_name, BackgroundWorker::bgw_notify_pid, DEBUG1, ereport, errcode(), errdetail_plural(), errhint(), errmsg(), IsUnderPostmaster, LOG, malloc, max_worker_processes, NULL, 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(), and ApplyLauncherRegister().

850 {
851  RegisteredBgWorker *rw;
852  static int numworkers = 0;
853 
854  if (!IsUnderPostmaster)
855  ereport(DEBUG1,
856  (errmsg("registering background worker \"%s\"", worker->bgw_name)));
857 
859  strcmp(worker->bgw_library_name, "postgres") != 0)
860  {
861  if (!IsUnderPostmaster)
862  ereport(LOG,
863  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
864  errmsg("background worker \"%s\": must be registered in shared_preload_libraries",
865  worker->bgw_name)));
866  return;
867  }
868 
869  if (!SanityCheckBackgroundWorker(worker, LOG))
870  return;
871 
872  if (worker->bgw_notify_pid != 0)
873  {
874  ereport(LOG,
875  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
876  errmsg("background worker \"%s\": only dynamic background workers can request notification",
877  worker->bgw_name)));
878  return;
879  }
880 
881  /*
882  * Enforce maximum number of workers. Note this is overly restrictive: we
883  * could allow more non-shmem-connected workers, because these don't count
884  * towards the MAX_BACKENDS limit elsewhere. For now, it doesn't seem
885  * important to relax this restriction.
886  */
887  if (++numworkers > max_worker_processes)
888  {
889  ereport(LOG,
890  (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
891  errmsg("too many background workers"),
892  errdetail_plural("Up to %d background worker can be registered with the current settings.",
893  "Up to %d background workers can be registered with the current settings.",
896  errhint("Consider increasing the configuration parameter \"max_worker_processes\".")));
897  return;
898  }
899 
900  /*
901  * Copy the registration data into the registered workers list.
902  */
903  rw = malloc(sizeof(RegisteredBgWorker));
904  if (rw == NULL)
905  {
906  ereport(LOG,
907  (errcode(ERRCODE_OUT_OF_MEMORY),
908  errmsg("out of memory")));
909  return;
910  }
911 
912  rw->rw_worker = *worker;
913  rw->rw_backend = NULL;
914  rw->rw_pid = 0;
915  rw->rw_child_slot = 0;
916  rw->rw_crashed_at = 0;
917  rw->rw_terminate = false;
918 
920 }
struct bkend * rw_backend
#define DEBUG1
Definition: elog.h:25
int errhint(const char *fmt,...)
Definition: elog.c:987
bool process_shared_preload_libraries_in_progress
Definition: miscinit.c:1417
static void slist_push_head(slist_head *head, slist_node *node)
Definition: ilist.h:574
int errcode(int sqlerrcode)
Definition: elog.c:575
#define LOG
Definition: elog.h:26
#define malloc(a)
Definition: header.h:50
slist_head BackgroundWorkerList
Definition: bgworker.c:43
bool IsUnderPostmaster
Definition: globals.c:100
#define ereport(elevel, rest)
Definition: elog.h:122
static bool SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
Definition: bgworker.c:581
#define NULL
Definition: c.h:229
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
int errdetail_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:965
int errmsg(const char *fmt,...)
Definition: elog.c:797
pid_t bgw_notify_pid
Definition: bgworker.h:98
int max_worker_processes
Definition: globals.c:124
BackgroundWorker rw_worker
char bgw_library_name[BGW_MAXLEN]
Definition: bgworker.h:94
bool RegisterDynamicBackgroundWorker ( BackgroundWorker worker,
BackgroundWorkerHandle **  handle 
)

Definition at line 933 of file bgworker.c.

References Assert, 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 LaunchParallelWorkers(), logicalrep_worker_launch(), setup_background_workers(), and worker_spi_launch().

935 {
936  int slotno;
937  bool success = false;
938  bool parallel;
939  uint64 generation = 0;
940 
941  /*
942  * We can't register dynamic background workers from the postmaster. If
943  * this is a standalone backend, we're the only process and can't start
944  * any more. In a multi-process environment, it might be theoretically
945  * possible, but we don't currently support it due to locking
946  * considerations; see comments on the BackgroundWorkerSlot data
947  * structure.
948  */
949  if (!IsUnderPostmaster)
950  return false;
951 
952  if (!SanityCheckBackgroundWorker(worker, ERROR))
953  return false;
954 
955  parallel = (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0;
956 
957  LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
958 
959  /*
960  * If this is a parallel worker, check whether there are already too many
961  * parallel workers; if so, don't register another one. Our view of
962  * parallel_terminate_count may be slightly stale, but that doesn't really
963  * matter: we would have gotten the same result if we'd arrived here
964  * slightly earlier anyway. There's no help for it, either, since the
965  * postmaster must not take locks; a memory barrier wouldn't guarantee
966  * anything useful.
967  */
971  {
975  LWLockRelease(BackgroundWorkerLock);
976  return false;
977  }
978 
979  /*
980  * Look for an unused slot. If we find one, grab it.
981  */
982  for (slotno = 0; slotno < BackgroundWorkerData->total_slots; ++slotno)
983  {
985 
986  if (!slot->in_use)
987  {
988  memcpy(&slot->worker, worker, sizeof(BackgroundWorker));
989  slot->pid = InvalidPid; /* indicates not started yet */
990  slot->generation++;
991  slot->terminate = false;
992  generation = slot->generation;
993  if (parallel)
995 
996  /*
997  * Make sure postmaster doesn't see the slot as in use before it
998  * sees the new contents.
999  */
1000  pg_write_barrier();
1001 
1002  slot->in_use = true;
1003  success = true;
1004  break;
1005  }
1006  }
1007 
1008  LWLockRelease(BackgroundWorkerLock);
1009 
1010  /* If we found a slot, tell the postmaster to notice the change. */
1011  if (success)
1013 
1014  /*
1015  * If we found a slot and the user has provided a handle, initialize it.
1016  */
1017  if (success && handle)
1018  {
1019  *handle = palloc(sizeof(BackgroundWorkerHandle));
1020  (*handle)->slot = slotno;
1021  (*handle)->generation = generation;
1022  }
1023 
1024  return success;
1025 }
int max_parallel_workers
Definition: globals.c:125
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:67
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
#define ERROR
Definition: elog.h:43
static bool success
Definition: pg_basebackup.c:96
uint32 parallel_register_count
Definition: bgworker.c:100
bool IsUnderPostmaster
Definition: globals.c:100
static bool SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
Definition: bgworker.c:581
#define Assert(condition)
Definition: c.h:675
BackgroundWorker worker
Definition: bgworker.c:83
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
void * palloc(Size size)
Definition: mcxt.c:849
uint32 parallel_terminate_count
Definition: bgworker.c:101
#define pg_write_barrier()
Definition: atomics.h:162
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:113
#define MAX_PARALLEL_WORKER_LIMIT
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
#define InvalidPid
Definition: miscadmin.h:31
void ReportBackgroundWorkerExit ( slist_mutable_iter cur)

Definition at line 457 of file bgworker.c.

References Assert, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, slist_mutable_iter::cur, ForgetBackgroundWorker(), max_worker_processes, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SIGUSR1, slist_container, and BackgroundWorkerArray::slot.

Referenced by CleanupBackgroundWorker().

458 {
459  RegisteredBgWorker *rw;
460  BackgroundWorkerSlot *slot;
461  int notify_pid;
462 
463  rw = slist_container(RegisteredBgWorker, rw_lnode, cur->cur);
464 
467  slot->pid = rw->rw_pid;
468  notify_pid = rw->rw_worker.bgw_notify_pid;
469 
470  /*
471  * If this worker is slated for deregistration, do that before notifying
472  * the process which started it. Otherwise, if that process tries to
473  * reuse the slot immediately, it might not be available yet. In theory
474  * that could happen anyway if the process checks slot->pid at just the
475  * wrong moment, but this makes the window narrower.
476  */
477  if (rw->rw_terminate ||
480 
481  if (notify_pid != 0)
482  kill(notify_pid, SIGUSR1);
483 }
#define SIGUSR1
Definition: win32.h:202
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
slist_node * cur
Definition: ilist.h:241
int bgw_restart_time
Definition: bgworker.h:93
void ForgetBackgroundWorker(slist_mutable_iter *cur)
Definition: bgworker.c:410
#define BGW_NEVER_RESTART
Definition: bgworker.h:84
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define Assert(condition)
Definition: c.h:675
pid_t bgw_notify_pid
Definition: bgworker.h:98
int max_worker_processes
Definition: globals.c:124
BackgroundWorker rw_worker
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
void ReportBackgroundWorkerPID ( RegisteredBgWorker rw)

Definition at line 438 of file bgworker.c.

References Assert, BackgroundWorker::bgw_notify_pid, max_worker_processes, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, SIGUSR1, and BackgroundWorkerArray::slot.

Referenced by BackgroundWorkerStateChange(), and do_start_bgworker().

439 {
440  BackgroundWorkerSlot *slot;
441 
444  slot->pid = rw->rw_pid;
445 
446  if (rw->rw_worker.bgw_notify_pid != 0)
447  kill(rw->rw_worker.bgw_notify_pid, SIGUSR1);
448 }
#define SIGUSR1
Definition: win32.h:202
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
#define Assert(condition)
Definition: c.h:675
pid_t bgw_notify_pid
Definition: bgworker.h:98
int max_worker_processes
Definition: globals.c:124
BackgroundWorker rw_worker
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
void ResetBackgroundWorkerCrashTimes ( void  )

Definition at line 513 of file bgworker.c.

References Assert, BackgroundWorker::bgw_flags, BGW_NEVER_RESTART, BackgroundWorker::bgw_restart_time, BGWORKER_CLASS_PARALLEL, slist_mutable_iter::cur, ForgetBackgroundWorker(), RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_worker, slist_container, and slist_foreach_modify.

Referenced by PostmasterStateMachine().

514 {
515  slist_mutable_iter iter;
516 
518  {
519  RegisteredBgWorker *rw;
520 
521  rw = slist_container(RegisteredBgWorker, rw_lnode, iter.cur);
522 
524  {
525  /*
526  * Workers marked BGW_NVER_RESTART shouldn't get relaunched after
527  * the crash, so forget about them. (If we wait until after the
528  * crash to forget about them, and they are parallel workers,
529  * parallel_terminate_count will get incremented after we've
530  * already zeroed parallel_register_count, which would be bad.)
531  */
532  ForgetBackgroundWorker(&iter);
533  }
534  else
535  {
536  /*
537  * The accounting which we do via parallel_register_count and
538  * parallel_terminate_count would get messed up if a worker marked
539  * parallel could survive a crash and restart cycle. All such
540  * workers should be marked BGW_NEVER_RESTART, and thus control
541  * should never reach this branch.
542  */
544 
545  /*
546  * Allow this worker to be restarted immediately after we finish
547  * resetting.
548  */
549  rw->rw_crashed_at = 0;
550  }
551  }
552 }
slist_node * cur
Definition: ilist.h:241
int bgw_restart_time
Definition: bgworker.h:93
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:67
#define slist_foreach_modify(iter, lhead)
Definition: ilist.h:716
slist_head BackgroundWorkerList
Definition: bgworker.c:43
void ForgetBackgroundWorker(slist_mutable_iter *cur)
Definition: bgworker.c:410
#define BGW_NEVER_RESTART
Definition: bgworker.h:84
#define slist_container(type, membername, ptr)
Definition: ilist.h:674
#define Assert(condition)
Definition: c.h:675
BackgroundWorker rw_worker
static bool SanityCheckBackgroundWorker ( BackgroundWorker worker,
int  elevel 
)
static

Definition at line 581 of file bgworker.c.

References BackgroundWorker::bgw_flags, BackgroundWorker::bgw_name, BGW_NEVER_RESTART, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_CLASS_PARALLEL, BGWORKER_SHMEM_ACCESS, BgWorkerStart_PostmasterStart, ereport, errcode(), errmsg(), and USECS_PER_DAY.

Referenced by RegisterBackgroundWorker(), and RegisterDynamicBackgroundWorker().

582 {
583  /* sanity check for flags */
585  {
586  if (!(worker->bgw_flags & BGWORKER_SHMEM_ACCESS))
587  {
588  ereport(elevel,
589  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
590  errmsg("background worker \"%s\": must attach to shared memory in order to request a database connection",
591  worker->bgw_name)));
592  return false;
593  }
594 
596  {
597  ereport(elevel,
598  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
599  errmsg("background worker \"%s\": cannot request database access if starting at postmaster start",
600  worker->bgw_name)));
601  return false;
602  }
603 
604  /* XXX other checks? */
605  }
606 
607  if ((worker->bgw_restart_time < 0 &&
608  worker->bgw_restart_time != BGW_NEVER_RESTART) ||
609  (worker->bgw_restart_time > USECS_PER_DAY / 1000))
610  {
611  ereport(elevel,
612  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
613  errmsg("background worker \"%s\": invalid restart interval",
614  worker->bgw_name)));
615  return false;
616  }
617 
618  /*
619  * Parallel workers may not be configured for restart, because the
620  * parallel_register_count/parallel_terminate_count accounting can't
621  * handle parallel workers lasting through a crash-and-restart cycle.
622  */
623  if (worker->bgw_restart_time != BGW_NEVER_RESTART &&
624  (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
625  {
626  ereport(elevel,
627  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
628  errmsg("background worker \"%s\": parallel workers may not be configured for restart",
629  worker->bgw_name)));
630  return false;
631  }
632 
633  return true;
634 }
int bgw_restart_time
Definition: bgworker.h:93
int errcode(int sqlerrcode)
Definition: elog.c:575
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:67
#define BGWORKER_SHMEM_ACCESS
Definition: bgworker.h:52
#define BGW_NEVER_RESTART
Definition: bgworker.h:84
#define USECS_PER_DAY
Definition: timestamp.h:91
#define ereport(elevel, rest)
Definition: elog.h:122
static int elevel
Definition: vacuumlazy.c:137
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:59
BgWorkerStartTime bgw_start_time
Definition: bgworker.h:92
int errmsg(const char *fmt,...)
Definition: elog.c:797
void StartBackgroundWorker ( void  )

Definition at line 700 of file bgworker.c.

References BaseInit(), BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BackgroundWorker::bgw_name, BGWORKER_BACKEND_DATABASE_CONNECTION, bgworker_die(), bgworker_quickdie(), BGWORKER_SHMEM_ACCESS, bgworker_sigusr1_handler(), buf, dsm_detach_all(), elog, EmitErrorReport(), error_context_stack, FATAL, FloatExceptionHandler(), HOLD_INTERRUPTS, init_ps_display(), InitializeTimeouts(), InitProcess(), InitProcessing, IsBackgroundWorker, LookupBackgroundWorkerFunction(), MAXPGPATH, MyBgworkerEntry, NULL, PG_exception_stack, pg_usleep(), PGSharedMemoryDetach(), PostAuthDelay, pqsignal(), proc_exit(), procsignal_sigusr1_handler(), SetProcessingMode, SIG_DFL, SIG_IGN, SIGCHLD, SIGHUP, SIGPIPE, SIGQUIT, SIGUSR1, SIGUSR2, snprintf(), and StatementCancelHandler().

Referenced by do_start_bgworker().

701 {
702  sigjmp_buf local_sigjmp_buf;
703  char buf[MAXPGPATH];
705  bgworker_main_type entrypt;
706 
707  if (worker == NULL)
708  elog(FATAL, "unable to find bgworker entry");
709 
710  IsBackgroundWorker = true;
711 
712  /* Identify myself via ps */
713  snprintf(buf, MAXPGPATH, "bgworker: %s", worker->bgw_name);
714  init_ps_display(buf, "", "", "");
715 
716  /*
717  * If we're not supposed to have shared memory access, then detach from
718  * shared memory. If we didn't request shared memory access, the
719  * postmaster won't force a cluster-wide restart if we exit unexpectedly,
720  * so we'd better make sure that we don't mess anything up that would
721  * require that sort of cleanup.
722  */
723  if ((worker->bgw_flags & BGWORKER_SHMEM_ACCESS) == 0)
724  {
725  dsm_detach_all();
727  }
728 
730 
731  /* Apply PostAuthDelay */
732  if (PostAuthDelay > 0)
733  pg_usleep(PostAuthDelay * 1000000L);
734 
735  /*
736  * Set up signal handlers.
737  */
739  {
740  /*
741  * SIGINT is used to signal canceling the current action
742  */
746 
747  /* XXX Any other handlers needed here? */
748  }
749  else
750  {
751  pqsignal(SIGINT, SIG_IGN);
753  pqsignal(SIGFPE, SIG_IGN);
754  }
755  pqsignal(SIGTERM, bgworker_die);
757 
759  InitializeTimeouts(); /* establishes SIGALRM handler */
760 
764 
765  /*
766  * If an exception is encountered, processing resumes here.
767  *
768  * See notes in postgres.c about the design of this coding.
769  */
770  if (sigsetjmp(local_sigjmp_buf, 1) != 0)
771  {
772  /* Since not using PG_TRY, must reset error stack by hand */
774 
775  /* Prevent interrupts while cleaning up */
776  HOLD_INTERRUPTS();
777 
778  /* Report the error to the server log */
779  EmitErrorReport();
780 
781  /*
782  * Do we need more cleanup here? For shmem-connected bgworkers, we
783  * will call InitProcess below, which will install ProcKill as exit
784  * callback. That will take care of releasing locks, etc.
785  */
786 
787  /* and go away */
788  proc_exit(1);
789  }
790 
791  /* We can now handle ereport(ERROR) */
792  PG_exception_stack = &local_sigjmp_buf;
793 
794  /*
795  * If the background worker request shared memory access, set that up now;
796  * else, detach all shared memory segments.
797  */
798  if (worker->bgw_flags & BGWORKER_SHMEM_ACCESS)
799  {
800  /*
801  * Early initialization. Some of this could be useful even for
802  * background workers that aren't using shared memory, but they can
803  * call the individual startup routines for those subsystems if
804  * needed.
805  */
806  BaseInit();
807 
808  /*
809  * Create a per-backend PGPROC struct in shared memory, except in the
810  * EXEC_BACKEND case where this was done in SubPostmasterMain. We must
811  * do this before we can use LWLocks (and in the EXEC_BACKEND case we
812  * already had to do some stuff with LWLocks).
813  */
814 #ifndef EXEC_BACKEND
815  InitProcess();
816 #endif
817  }
818 
819  /*
820  * Look up the entry point function, loading its library if necessary.
821  */
823  worker->bgw_function_name);
824 
825  /*
826  * Note that in normal processes, we would call InitPostgres here. For a
827  * worker, however, we don't know what database to connect to, yet; so we
828  * need to wait until the user code does it via
829  * BackgroundWorkerInitializeConnection().
830  */
831 
832  /*
833  * Now invoke the user-defined worker code
834  */
835  entrypt(worker->bgw_main_arg);
836 
837  /* ... and if it returns, we're done */
838  proc_exit(0);
839 }
void InitializeTimeouts(void)
Definition: timeout.c:340
static void bgworker_sigusr1_handler(SIGNAL_ARGS)
Definition: bgworker.c:684
#define SIGUSR1
Definition: win32.h:202
void proc_exit(int code)
Definition: ipc.c:99
#define SetProcessingMode(mode)
Definition: miscadmin.h:371
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:189
void BaseInit(void)
Definition: postinit.c:517
int snprintf(char *str, size_t count, const char *fmt,...) pg_attribute_printf(3
#define BGWORKER_SHMEM_ACCESS
Definition: bgworker.h:52
char bgw_function_name[BGW_MAXLEN]
Definition: bgworker.h:95
#define SIGQUIT
Definition: win32.h:189
void PGSharedMemoryDetach(void)
Definition: sysv_shmem.c:789
void StatementCancelHandler(SIGNAL_ARGS)
Definition: postgres.c:2654
bool IsBackgroundWorker
Definition: globals.c:102
ErrorContextCallback * error_context_stack
Definition: elog.c:88
void pg_usleep(long microsec)
Definition: signal.c:53
Datum bgw_main_arg
Definition: bgworker.h:96
#define SIG_IGN
Definition: win32.h:185
#define FATAL
Definition: elog.h:52
void(* bgworker_main_type)(Datum main_arg)
Definition: bgworker.h:71
#define MAXPGPATH
void InitProcess(void)
Definition: proc.c:287
static char * buf
Definition: pg_test_fsync.c:66
static bgworker_main_type LookupBackgroundWorkerFunction(const char *libraryname, const char *funcname)
Definition: bgworker.c:1212
int PostAuthDelay
Definition: postgres.c:97
void EmitErrorReport(void)
Definition: elog.c:1446
#define SIGPIPE
Definition: win32.h:193
#define SIGHUP
Definition: win32.h:188
#define SIG_DFL
Definition: win32.h:183
pqsigfunc pqsignal(int signum, pqsigfunc handler)
Definition: signal.c:168
#define NULL
Definition: c.h:229
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:59
void dsm_detach_all(void)
Definition: dsm.c:666
sigjmp_buf * PG_exception_stack
Definition: elog.c:90
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
void FloatExceptionHandler(SIGNAL_ARGS)
Definition: postgres.c:2675
static void bgworker_die(SIGNAL_ARGS)
Definition: bgworker.c:667
#define elog
Definition: elog.h:219
static void bgworker_quickdie(SIGNAL_ARGS)
Definition: bgworker.c:637
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:260
#define SIGCHLD
Definition: win32.h:198
char bgw_library_name[BGW_MAXLEN]
Definition: bgworker.h:94
#define SIGUSR2
Definition: win32.h:203
void init_ps_display(const char *username, const char *dbname, const char *host_info, const char *initial_str)
Definition: ps_status.c:244
void TerminateBackgroundWorker ( BackgroundWorkerHandle handle)

Definition at line 1171 of file bgworker.c.

References Assert, 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().

1172 {
1173  BackgroundWorkerSlot *slot;
1174  bool signal_postmaster = false;
1175 
1176  Assert(handle->slot < max_worker_processes);
1177  slot = &BackgroundWorkerData->slot[handle->slot];
1178 
1179  /* Set terminate flag in shared memory, unless slot has been reused. */
1180  LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1181  if (handle->generation == slot->generation)
1182  {
1183  slot->terminate = true;
1184  signal_postmaster = true;
1185  }
1186  LWLockRelease(BackgroundWorkerLock);
1187 
1188  /* Make sure the postmaster notices the change to shared memory. */
1189  if (signal_postmaster)
1191 }
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:111
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
#define Assert(condition)
Definition: c.h:675
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
int max_worker_processes
Definition: globals.c:124
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:113
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:102
BgwHandleStatus WaitForBackgroundWorkerShutdown ( BackgroundWorkerHandle handle)

Definition at line 1132 of file bgworker.c.

References BGWH_POSTMASTER_DIED, BGWH_STOPPED, CHECK_FOR_INTERRUPTS, GetBackgroundWorkerPid(), MyProc, PGPROC::procLatch, ResetLatch(), status(), WAIT_EVENT_BGWORKER_SHUTDOWN, WaitLatch(), WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by WaitForParallelWorkersToExit().

1133 {
1135  int rc;
1136 
1137  for (;;)
1138  {
1139  pid_t pid;
1140 
1142 
1143  status = GetBackgroundWorkerPid(handle, &pid);
1144  if (status == BGWH_STOPPED)
1145  break;
1146 
1147  rc = WaitLatch(&MyProc->procLatch,
1150 
1151  if (rc & WL_POSTMASTER_DEATH)
1152  {
1153  status = BGWH_POSTMASTER_DIED;
1154  break;
1155  }
1156 
1158  }
1159 
1160  return status;
1161 }
PGPROC * MyProc
Definition: proc.c:67
void ResetLatch(volatile Latch *latch)
Definition: latch.c:498
Latch procLatch
Definition: proc.h:103
int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:336
BgwHandleStatus
Definition: bgworker.h:101
#define WL_POSTMASTER_DEATH
Definition: latch.h:128
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:97
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:224
#define WL_LATCH_SET
Definition: latch.h:124
BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1041
BgwHandleStatus WaitForBackgroundWorkerStartup ( BackgroundWorkerHandle handle,
pid_t *  pidp 
)

Definition at line 1090 of file bgworker.c.

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

Referenced by worker_spi_launch().

1091 {
1093  int rc;
1094 
1095  for (;;)
1096  {
1097  pid_t pid;
1098 
1100 
1101  status = GetBackgroundWorkerPid(handle, &pid);
1102  if (status == BGWH_STARTED)
1103  *pidp = pid;
1104  if (status != BGWH_NOT_YET_STARTED)
1105  break;
1106 
1107  rc = WaitLatch(MyLatch,
1110 
1111  if (rc & WL_POSTMASTER_DEATH)
1112  {
1113  status = BGWH_POSTMASTER_DIED;
1114  break;
1115  }
1116 
1118  }
1119 
1120  return status;
1121 }
void ResetLatch(volatile Latch *latch)
Definition: latch.c:498
int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:336
BgwHandleStatus
Definition: bgworker.h:101
#define WL_POSTMASTER_DEATH
Definition: latch.h:128
struct Latch * MyLatch
Definition: globals.c:51
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:97
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:224
#define WL_LATCH_SET
Definition: latch.h:124
BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1041

Variable Documentation

BackgroundWorkerArray* BackgroundWorkerData
static

Definition at line 111 of file bgworker.c.

slist_head BackgroundWorkerList = SLIST_STATIC_INIT(BackgroundWorkerList)

Definition at line 120 of file bgworker.c.

Referenced by LookupBackgroundWorkerFunction().

const char* fn_name

Definition at line 119 of file bgworker.c.

Referenced by LookupBackgroundWorkerFunction().

const { ... } InternalBGWorkers[]
Initial value:
=
{
{
"ParallelWorkerMain", ParallelWorkerMain
},
{
"ApplyLauncherMain", ApplyLauncherMain
},
{
"ApplyWorkerMain", ApplyWorkerMain
}
}
void ApplyLauncherMain(Datum main_arg)
Definition: launcher.c:786
void ParallelWorkerMain(Datum main_arg)
Definition: parallel.c:922
void ApplyWorkerMain(Datum main_arg)
Definition: worker.c:1449

Referenced by LookupBackgroundWorkerFunction().