PostgreSQL Source Code git master
bgworker_internals.h File Reference
#include "datatype/timestamp.h"
#include "lib/ilist.h"
#include "postmaster/bgworker.h"
Include dependency graph for bgworker_internals.h:
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Data Structures

struct  RegisteredBgWorker
 

Macros

#define MAX_PARALLEL_WORKER_LIMIT   1024
 

Typedefs

typedef struct RegisteredBgWorker RegisteredBgWorker
 

Functions

Size BackgroundWorkerShmemSize (void)
 
void BackgroundWorkerShmemInit (void)
 
void BackgroundWorkerStateChange (bool allow_new_workers)
 
void ForgetBackgroundWorker (RegisteredBgWorker *rw)
 
void ReportBackgroundWorkerPID (RegisteredBgWorker *rw)
 
void ReportBackgroundWorkerExit (RegisteredBgWorker *rw)
 
void BackgroundWorkerStopNotifications (pid_t pid)
 
void ForgetUnstartedBackgroundWorkers (void)
 
void ResetBackgroundWorkerCrashTimes (void)
 
pg_noreturn void BackgroundWorkerMain (const void *startup_data, size_t startup_data_len)
 

Variables

PGDLLIMPORT dlist_head BackgroundWorkerList
 

Macro Definition Documentation

◆ MAX_PARALLEL_WORKER_LIMIT

#define MAX_PARALLEL_WORKER_LIMIT   1024

Definition at line 24 of file bgworker_internals.h.

Typedef Documentation

◆ RegisteredBgWorker

Function Documentation

◆ BackgroundWorkerMain()

pg_noreturn void BackgroundWorkerMain ( const void *  startup_data,
size_t  startup_data_len 
)

Definition at line 717 of file bgworker.c.

718{
719 sigjmp_buf local_sigjmp_buf;
720 BackgroundWorker *worker;
721 bgworker_main_type entrypt;
722
723 if (startup_data == NULL)
724 elog(FATAL, "unable to find bgworker entry");
725 Assert(startup_data_len == sizeof(BackgroundWorker));
727 memcpy(worker, startup_data, sizeof(BackgroundWorker));
728
729 /*
730 * Now that we're done reading the startup data, release postmaster's
731 * working memory context.
732 */
734 {
736 PostmasterContext = NULL;
737 }
738
739 MyBgworkerEntry = worker;
741 init_ps_display(worker->bgw_name);
742
744
745 /* Apply PostAuthDelay */
746 if (PostAuthDelay > 0)
747 pg_usleep(PostAuthDelay * 1000000L);
748
749 /*
750 * Set up signal handlers.
751 */
753 {
754 /*
755 * SIGINT is used to signal canceling the current action
756 */
760
761 /* XXX Any other handlers needed here? */
762 }
763 else
764 {
765 pqsignal(SIGINT, SIG_IGN);
766 pqsignal(SIGUSR1, SIG_IGN);
767 pqsignal(SIGFPE, SIG_IGN);
768 }
769 pqsignal(SIGTERM, bgworker_die);
770 /* SIGQUIT handler was already set up by InitPostmasterChild */
771 pqsignal(SIGHUP, SIG_IGN);
772
773 InitializeTimeouts(); /* establishes SIGALRM handler */
774
775 pqsignal(SIGPIPE, SIG_IGN);
776 pqsignal(SIGUSR2, SIG_IGN);
777 pqsignal(SIGCHLD, SIG_DFL);
778
779 /*
780 * If an exception is encountered, processing resumes here.
781 *
782 * We just need to clean up, report the error, and go away.
783 */
784 if (sigsetjmp(local_sigjmp_buf, 1) != 0)
785 {
786 /* Since not using PG_TRY, must reset error stack by hand */
787 error_context_stack = NULL;
788
789 /* Prevent interrupts while cleaning up */
791
792 /*
793 * sigsetjmp will have blocked all signals, but we may need to accept
794 * signals while communicating with our parallel leader. Once we've
795 * done HOLD_INTERRUPTS() it should be safe to unblock signals.
796 */
798
799 /* Report the error to the parallel leader and the server log */
801
802 /*
803 * Do we need more cleanup here? For shmem-connected bgworkers, we
804 * will call InitProcess below, which will install ProcKill as exit
805 * callback. That will take care of releasing locks, etc.
806 */
807
808 /* and go away */
809 proc_exit(1);
810 }
811
812 /* We can now handle ereport(ERROR) */
813 PG_exception_stack = &local_sigjmp_buf;
814
815 /*
816 * Create a per-backend PGPROC struct in shared memory. We must do this
817 * before we can use LWLocks or access any shared memory.
818 */
819 InitProcess();
820
821 /*
822 * Early initialization.
823 */
824 BaseInit();
825
826 /*
827 * Look up the entry point function, loading its library if necessary.
828 */
830 worker->bgw_function_name);
831
832 /*
833 * Note that in normal processes, we would call InitPostgres here. For a
834 * worker, however, we don't know what database to connect to, yet; so we
835 * need to wait until the user code does it via
836 * BackgroundWorkerInitializeConnection().
837 */
838
839 /*
840 * Now invoke the user-defined worker code
841 */
842 entrypt(worker->bgw_main_arg);
843
844 /* ... and if it returns, we're done */
845 proc_exit(0);
846}
void BackgroundWorkerUnblockSignals(void)
Definition: bgworker.c:926
static bgworker_main_type LookupBackgroundWorkerFunction(const char *libraryname, const char *funcname)
Definition: bgworker.c:1337
static void bgworker_die(SIGNAL_ARGS)
Definition: bgworker.c:703
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:60
void(* bgworker_main_type)(Datum main_arg)
Definition: bgworker.h:72
void EmitErrorReport(void)
Definition: elog.c:1687
ErrorContextCallback * error_context_stack
Definition: elog.c:94
sigjmp_buf * PG_exception_stack
Definition: elog.c:96
#define FATAL
Definition: elog.h:41
#define elog(elevel,...)
Definition: elog.h:225
Assert(PointerIsAligned(start, uint64))
void proc_exit(int code)
Definition: ipc.c:104
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:1181
MemoryContext TopMemoryContext
Definition: mcxt.c:149
MemoryContext PostmasterContext
Definition: mcxt.c:151
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:454
@ InitProcessing
Definition: miscadmin.h:470
#define GetProcessingMode()
Definition: miscadmin.h:480
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:133
@ B_BG_WORKER
Definition: miscadmin.h:345
BackendType MyBackendType
Definition: miscinit.c:64
#define pqsignal
Definition: port.h:521
int PostAuthDelay
Definition: postgres.c:99
void FloatExceptionHandler(SIGNAL_ARGS)
Definition: postgres.c:3051
void StatementCancelHandler(SIGNAL_ARGS)
Definition: postgres.c:3034
void BaseInit(void)
Definition: postinit.c:616
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:199
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:673
void init_ps_display(const char *fixed_part)
Definition: ps_status.c:269
void pg_usleep(long microsec)
Definition: signal.c:53
void InitProcess(void)
Definition: proc.c:341
char bgw_function_name[BGW_MAXLEN]
Definition: bgworker.h:97
Datum bgw_main_arg
Definition: bgworker.h:98
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:91
char bgw_library_name[MAXPGPATH]
Definition: bgworker.h:96
void InitializeTimeouts(void)
Definition: timeout.c:470
#define SIGCHLD
Definition: win32_port.h:168
#define SIGHUP
Definition: win32_port.h:158
#define SIGPIPE
Definition: win32_port.h:163
#define SIGUSR1
Definition: win32_port.h:170
#define SIGUSR2
Definition: win32_port.h:171

References Assert(), B_BG_WORKER, BackgroundWorkerUnblockSignals(), 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(), elog, EmitErrorReport(), error_context_stack, FATAL, FloatExceptionHandler(), GetProcessingMode, HOLD_INTERRUPTS, init_ps_display(), InitializeTimeouts(), InitProcess(), InitProcessing, LookupBackgroundWorkerFunction(), MemoryContextAlloc(), MemoryContextDelete(), MyBackendType, MyBgworkerEntry, PG_exception_stack, pg_usleep(), PostAuthDelay, PostmasterContext, pqsignal, proc_exit(), procsignal_sigusr1_handler(), SIGCHLD, SIGHUP, SIGPIPE, SIGUSR1, SIGUSR2, StatementCancelHandler(), and TopMemoryContext.

◆ BackgroundWorkerShmemInit()

void BackgroundWorkerShmemInit ( void  )

Definition at line 162 of file bgworker.c.

163{
164 bool found;
165
166 BackgroundWorkerData = ShmemInitStruct("Background Worker Data",
168 &found);
170 {
171 dlist_iter iter;
172 int slotno = 0;
173
177
178 /*
179 * Copy contents of worker list into shared memory. Record the shared
180 * memory slot assigned to each worker. This ensures a 1-to-1
181 * correspondence between the postmaster's private list and the array
182 * in shared memory.
183 */
185 {
188
189 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
191 slot->in_use = true;
192 slot->terminate = false;
193 slot->pid = InvalidPid;
194 slot->generation = 0;
195 rw->rw_shmem_slot = slotno;
196 rw->rw_worker.bgw_notify_pid = 0; /* might be reinit after crash */
197 memcpy(&slot->worker, &rw->rw_worker, sizeof(BackgroundWorker));
198 ++slotno;
199 }
200
201 /*
202 * Mark any remaining slots as not in use.
203 */
204 while (slotno < max_worker_processes)
205 {
207
208 slot->in_use = false;
209 ++slotno;
210 }
211 }
212 else
213 Assert(found);
214}
dlist_head BackgroundWorkerList
Definition: bgworker.c:40
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:108
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:146
bool IsUnderPostmaster
Definition: globals.c:119
int max_worker_processes
Definition: globals.c:143
#define dlist_foreach(iter, lhead)
Definition: ilist.h:623
#define dlist_container(type, membername, ptr)
Definition: ilist.h:593
#define InvalidPid
Definition: miscadmin.h:32
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:382
uint32 parallel_terminate_count
Definition: bgworker.c:98
uint32 parallel_register_count
Definition: bgworker.c:97
BackgroundWorkerSlot slot[FLEXIBLE_ARRAY_MEMBER]
Definition: bgworker.c:99
BackgroundWorker worker
Definition: bgworker.c:80
pid_t bgw_notify_pid
Definition: bgworker.h:100
BackgroundWorker rw_worker
dlist_node * cur
Definition: ilist.h:179

References Assert(), BackgroundWorkerData, BackgroundWorkerList, BackgroundWorkerShmemSize(), BackgroundWorker::bgw_notify_pid, dlist_iter::cur, dlist_container, dlist_foreach, 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(), BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by CreateOrAttachShmemStructs().

◆ BackgroundWorkerShmemSize()

Size BackgroundWorkerShmemSize ( void  )

Definition at line 146 of file bgworker.c.

147{
148 Size size;
149
150 /* Array of workers is variably sized. */
151 size = offsetof(BackgroundWorkerArray, slot);
153 sizeof(BackgroundWorkerSlot)));
154
155 return size;
156}
size_t Size
Definition: c.h:576
Size add_size(Size s1, Size s2)
Definition: shmem.c:488
Size mul_size(Size s1, Size s2)
Definition: shmem.c:505

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

Referenced by BackgroundWorkerShmemInit(), and CalculateShmemSize().

◆ BackgroundWorkerStateChange()

void BackgroundWorkerStateChange ( bool  allow_new_workers)

Definition at line 246 of file bgworker.c.

247{
248 int slotno;
249
250 /*
251 * The total number of slots stored in shared memory should match our
252 * notion of max_worker_processes. If it does not, something is very
253 * wrong. Further down, we always refer to this value as
254 * max_worker_processes, in case shared memory gets corrupted while we're
255 * looping.
256 */
258 {
259 ereport(LOG,
260 (errmsg("inconsistent background worker state (\"max_worker_processes\"=%d, total slots=%d)",
263 return;
264 }
265
266 /*
267 * Iterate through slots, looking for newly-registered workers or workers
268 * who must die.
269 */
270 for (slotno = 0; slotno < max_worker_processes; ++slotno)
271 {
274
275 if (!slot->in_use)
276 continue;
277
278 /*
279 * Make sure we don't see the in_use flag before the updated slot
280 * contents.
281 */
283
284 /* See whether we already know about this worker. */
286 if (rw != NULL)
287 {
288 /*
289 * In general, the worker data can't change after it's initially
290 * registered. However, someone can set the terminate flag.
291 */
292 if (slot->terminate && !rw->rw_terminate)
293 {
294 rw->rw_terminate = true;
295 if (rw->rw_pid != 0)
296 kill(rw->rw_pid, SIGTERM);
297 else
298 {
299 /* Report never-started, now-terminated worker as dead. */
301 }
302 }
303 continue;
304 }
305
306 /*
307 * If we aren't allowing new workers, then immediately mark it for
308 * termination; the next stanza will take care of cleaning it up.
309 * Doing this ensures that any process waiting for the worker will get
310 * awoken, even though the worker will never be allowed to run.
311 */
312 if (!allow_new_workers)
313 slot->terminate = true;
314
315 /*
316 * If the worker is marked for termination, we don't need to add it to
317 * the registered workers list; we can just free the slot. However, if
318 * bgw_notify_pid is set, the process that registered the worker may
319 * need to know that we've processed the terminate request, so be sure
320 * to signal it.
321 */
322 if (slot->terminate)
323 {
324 int notify_pid;
325
326 /*
327 * We need a memory barrier here to make sure that the load of
328 * bgw_notify_pid and the update of parallel_terminate_count
329 * complete before the store to in_use.
330 */
331 notify_pid = slot->worker.bgw_notify_pid;
332 if ((slot->worker.bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
334 slot->pid = 0;
335
337 slot->in_use = false;
338
339 if (notify_pid != 0)
340 kill(notify_pid, SIGUSR1);
341
342 continue;
343 }
344
345 /*
346 * Copy the registration data into the registered workers list.
347 */
349 sizeof(RegisteredBgWorker),
351 if (rw == NULL)
352 {
353 ereport(LOG,
354 (errcode(ERRCODE_OUT_OF_MEMORY),
355 errmsg("out of memory")));
356 return;
357 }
358
359 /*
360 * Copy strings in a paranoid way. If shared memory is corrupted, the
361 * source data might not even be NUL-terminated.
362 */
364 slot->worker.bgw_name, BGW_MAXLEN);
366 slot->worker.bgw_type, BGW_MAXLEN);
371
372 /*
373 * Copy various fixed-size fields.
374 *
375 * flags, start_time, and restart_time are examined by the postmaster,
376 * but nothing too bad will happen if they are corrupted. The
377 * remaining fields will only be examined by the child process. It
378 * might crash, but we won't.
379 */
384 memcpy(rw->rw_worker.bgw_extra, slot->worker.bgw_extra, BGW_EXTRALEN);
385
386 /*
387 * Copy the PID to be notified about state changes, but only if the
388 * postmaster knows about a backend with that PID. It isn't an error
389 * if the postmaster doesn't know about the PID, because the backend
390 * that requested the worker could have died (or been killed) just
391 * after doing so. Nonetheless, at least until we get some experience
392 * with how this plays out in the wild, log a message at a relative
393 * high debug level.
394 */
397 {
398 elog(DEBUG1, "worker notification PID %d is not valid",
399 (int) rw->rw_worker.bgw_notify_pid);
401 }
402
403 /* Initialize postmaster bookkeeping. */
404 rw->rw_pid = 0;
405 rw->rw_crashed_at = 0;
406 rw->rw_shmem_slot = slotno;
407 rw->rw_terminate = false;
408
409 /* Log it! */
411 (errmsg_internal("registering background worker \"%s\"",
412 rw->rw_worker.bgw_name)));
413
415 }
416}
void ascii_safe_strlcpy(char *dest, const char *src, size_t destsiz)
Definition: ascii.c:174
#define pg_memory_barrier()
Definition: atomics.h:143
#define pg_read_barrier()
Definition: atomics.h:156
void ReportBackgroundWorkerPID(RegisteredBgWorker *rw)
Definition: bgworker.c:461
static RegisteredBgWorker * FindRegisteredWorkerBySlotNumber(int slotno)
Definition: bgworker.c:221
#define BGW_EXTRALEN
Definition: bgworker.h:87
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:68
#define BGW_MAXLEN
Definition: bgworker.h:86
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1157
int errcode(int sqlerrcode)
Definition: elog.c:853
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define LOG
Definition: elog.h:31
#define DEBUG1
Definition: elog.h:30
#define ereport(elevel,...)
Definition: elog.h:149
#define MCXT_ALLOC_ZERO
Definition: fe_memutils.h:30
#define MCXT_ALLOC_NO_OOM
Definition: fe_memutils.h:29
static void dlist_push_head(dlist_head *head, dlist_node *node)
Definition: ilist.h:347
void * MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
Definition: mcxt.c:1238
#define MAXPGPATH
bool PostmasterMarkPIDForWorkerNotify(int pid)
Definition: postmaster.c:4429
int bgw_restart_time
Definition: bgworker.h:95
char bgw_type[BGW_MAXLEN]
Definition: bgworker.h:92
BgWorkerStartTime bgw_start_time
Definition: bgworker.h:94
char bgw_extra[BGW_EXTRALEN]
Definition: bgworker.h:99
#define kill(pid, sig)
Definition: win32_port.h:493

References ascii_safe_strlcpy(), BackgroundWorkerData, BackgroundWorkerList, 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, BackgroundWorker::bgw_type, BGWORKER_CLASS_PARALLEL, DEBUG1, dlist_push_head(), elog, ereport, errcode(), errmsg(), errmsg_internal(), FindRegisteredWorkerBySlotNumber(), BackgroundWorkerSlot::in_use, kill, LOG, max_worker_processes, MAXPGPATH, MCXT_ALLOC_NO_OOM, MCXT_ALLOC_ZERO, MemoryContextAllocExtended(), BackgroundWorkerArray::parallel_terminate_count, pg_memory_barrier, pg_read_barrier, BackgroundWorkerSlot::pid, PostmasterContext, PostmasterMarkPIDForWorkerNotify(), ReportBackgroundWorkerPID(), RegisteredBgWorker::rw_crashed_at, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_terminate, RegisteredBgWorker::rw_worker, SIGUSR1, BackgroundWorkerArray::slot, BackgroundWorkerSlot::terminate, BackgroundWorkerArray::total_slots, and BackgroundWorkerSlot::worker.

Referenced by process_pm_pmsignal().

◆ BackgroundWorkerStopNotifications()

void BackgroundWorkerStopNotifications ( pid_t  pid)

Definition at line 514 of file bgworker.c.

515{
516 dlist_iter iter;
517
519 {
521
522 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
523 if (rw->rw_worker.bgw_notify_pid == pid)
525 }
526}

References BackgroundWorkerList, BackgroundWorker::bgw_notify_pid, dlist_iter::cur, dlist_container, dlist_foreach, and RegisteredBgWorker::rw_worker.

Referenced by CleanupBackend().

◆ ForgetBackgroundWorker()

void ForgetBackgroundWorker ( RegisteredBgWorker rw)

Definition at line 429 of file bgworker.c.

430{
432
435 Assert(slot->in_use);
436
437 /*
438 * We need a memory barrier here to make sure that the update of
439 * parallel_terminate_count completes before the store to in_use.
440 */
443
445 slot->in_use = false;
446
448 (errmsg_internal("unregistering background worker \"%s\"",
449 rw->rw_worker.bgw_name)));
450
452 pfree(rw);
453}
static void dlist_delete(dlist_node *node)
Definition: ilist.h:405
void pfree(void *pointer)
Definition: mcxt.c:1524

References Assert(), BackgroundWorkerData, BackgroundWorker::bgw_flags, BackgroundWorker::bgw_name, BGWORKER_CLASS_PARALLEL, DEBUG1, dlist_delete(), ereport, errmsg_internal(), BackgroundWorkerSlot::in_use, max_worker_processes, BackgroundWorkerArray::parallel_terminate_count, pfree(), pg_memory_barrier, RegisteredBgWorker::rw_lnode, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, and BackgroundWorkerArray::slot.

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

◆ ForgetUnstartedBackgroundWorkers()

void ForgetUnstartedBackgroundWorkers ( void  )

Definition at line 541 of file bgworker.c.

542{
544
546 {
549
550 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
553
554 /* If it's not yet started, and there's someone waiting ... */
555 if (slot->pid == InvalidPid &&
556 rw->rw_worker.bgw_notify_pid != 0)
557 {
558 /* ... then zap it, and notify the waiter */
559 int notify_pid = rw->rw_worker.bgw_notify_pid;
560
562 if (notify_pid != 0)
563 kill(notify_pid, SIGUSR1);
564 }
565 }
566}
void ForgetBackgroundWorker(RegisteredBgWorker *rw)
Definition: bgworker.c:429
#define dlist_foreach_modify(iter, lhead)
Definition: ilist.h:640
dlist_node * cur
Definition: ilist.h:200

References Assert(), BackgroundWorkerData, BackgroundWorkerList, BackgroundWorker::bgw_notify_pid, dlist_mutable_iter::cur, dlist_container, dlist_foreach_modify, ForgetBackgroundWorker(), InvalidPid, kill, max_worker_processes, BackgroundWorkerSlot::pid, RegisteredBgWorker::rw_shmem_slot, RegisteredBgWorker::rw_worker, SIGUSR1, and BackgroundWorkerArray::slot.

Referenced by PostmasterStateMachine().

◆ ReportBackgroundWorkerExit()

void ReportBackgroundWorkerExit ( RegisteredBgWorker rw)

Definition at line 483 of file bgworker.c.

484{
486 int notify_pid;
487
490 slot->pid = rw->rw_pid;
491 notify_pid = rw->rw_worker.bgw_notify_pid;
492
493 /*
494 * If this worker is slated for deregistration, do that before notifying
495 * the process which started it. Otherwise, if that process tries to
496 * reuse the slot immediately, it might not be available yet. In theory
497 * that could happen anyway if the process checks slot->pid at just the
498 * wrong moment, but this makes the window narrower.
499 */
500 if (rw->rw_terminate ||
503
504 if (notify_pid != 0)
505 kill(notify_pid, SIGUSR1);
506}
#define BGW_NEVER_RESTART
Definition: bgworker.h:85

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

Referenced by CleanupBackend().

◆ ReportBackgroundWorkerPID()

◆ ResetBackgroundWorkerCrashTimes()

void ResetBackgroundWorkerCrashTimes ( void  )

Definition at line 579 of file bgworker.c.

580{
582
584 {
586
587 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
588
590 {
591 /*
592 * Workers marked BGW_NEVER_RESTART shouldn't get relaunched after
593 * the crash, so forget about them. (If we wait until after the
594 * crash to forget about them, and they are parallel workers,
595 * parallel_terminate_count will get incremented after we've
596 * already zeroed parallel_register_count, which would be bad.)
597 */
599 }
600 else
601 {
602 /*
603 * The accounting which we do via parallel_register_count and
604 * parallel_terminate_count would get messed up if a worker marked
605 * parallel could survive a crash and restart cycle. All such
606 * workers should be marked BGW_NEVER_RESTART, and thus control
607 * should never reach this branch.
608 */
610
611 /*
612 * Allow this worker to be restarted immediately after we finish
613 * resetting.
614 */
615 rw->rw_crashed_at = 0;
616
617 /*
618 * If there was anyone waiting for it, they're history.
619 */
621 }
622 }
623}

References Assert(), BackgroundWorkerList, BackgroundWorker::bgw_flags, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BGWORKER_CLASS_PARALLEL, dlist_mutable_iter::cur, dlist_container, dlist_foreach_modify, ForgetBackgroundWorker(), RegisteredBgWorker::rw_crashed_at, and RegisteredBgWorker::rw_worker.

Referenced by PostmasterStateMachine().

Variable Documentation

◆ BackgroundWorkerList