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bgworker.c
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1/*--------------------------------------------------------------------
2 * bgworker.c
3 * POSTGRES pluggable background workers implementation
4 *
5 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
6 *
7 * IDENTIFICATION
8 * src/backend/postmaster/bgworker.c
9 *
10 *-------------------------------------------------------------------------
11 */
12
13#include "postgres.h"
14
15#include "access/parallel.h"
16#include "libpq/pqsignal.h"
17#include "miscadmin.h"
18#include "pgstat.h"
19#include "port/atomics.h"
24#include "storage/ipc.h"
25#include "storage/latch.h"
26#include "storage/lwlock.h"
27#include "storage/pmsignal.h"
28#include "storage/proc.h"
29#include "storage/procsignal.h"
30#include "storage/shmem.h"
31#include "tcop/tcopprot.h"
32#include "utils/ascii.h"
33#include "utils/memutils.h"
34#include "utils/ps_status.h"
35#include "utils/timeout.h"
36
37/*
38 * The postmaster's list of registered background workers, in private memory.
39 */
41
42/*
43 * BackgroundWorkerSlots exist in shared memory and can be accessed (via
44 * the BackgroundWorkerArray) by both the postmaster and by regular backends.
45 * However, the postmaster cannot take locks, even spinlocks, because this
46 * might allow it to crash or become wedged if shared memory gets corrupted.
47 * Such an outcome is intolerable. Therefore, we need a lockless protocol
48 * for coordinating access to this data.
49 *
50 * The 'in_use' flag is used to hand off responsibility for the slot between
51 * the postmaster and the rest of the system. When 'in_use' is false,
52 * the postmaster will ignore the slot entirely, except for the 'in_use' flag
53 * itself, which it may read. In this state, regular backends may modify the
54 * slot. Once a backend sets 'in_use' to true, the slot becomes the
55 * responsibility of the postmaster. Regular backends may no longer modify it,
56 * but the postmaster may examine it. Thus, a backend initializing a slot
57 * must fully initialize the slot - and insert a write memory barrier - before
58 * marking it as in use.
59 *
60 * As an exception, however, even when the slot is in use, regular backends
61 * may set the 'terminate' flag for a slot, telling the postmaster not
62 * to restart it. Once the background worker is no longer running, the slot
63 * will be released for reuse.
64 *
65 * In addition to coordinating with the postmaster, backends modifying this
66 * data structure must coordinate with each other. Since they can take locks,
67 * this is straightforward: any backend wishing to manipulate a slot must
68 * take BackgroundWorkerLock in exclusive mode. Backends wishing to read
69 * data that might get concurrently modified by other backends should take
70 * this lock in shared mode. No matter what, backends reading this data
71 * structure must be able to tolerate concurrent modifications by the
72 * postmaster.
73 */
75{
76 bool in_use;
78 pid_t pid; /* InvalidPid = not started yet; 0 = dead */
79 uint64 generation; /* incremented when slot is recycled */
82
83/*
84 * In order to limit the total number of parallel workers (according to
85 * max_parallel_workers GUC), we maintain the number of active parallel
86 * workers. Since the postmaster cannot take locks, two variables are used for
87 * this purpose: the number of registered parallel workers (modified by the
88 * backends, protected by BackgroundWorkerLock) and the number of terminated
89 * parallel workers (modified only by the postmaster, lockless). The active
90 * number of parallel workers is the number of registered workers minus the
91 * terminated ones. These counters can of course overflow, but it's not
92 * important here since the subtraction will still give the right number.
93 */
95{
101
103{
104 int slot;
106};
107
109
110/*
111 * List of internal background worker entry points. We need this for
112 * reasons explained in LookupBackgroundWorkerFunction(), below.
113 */
114static const struct
115{
116 const char *fn_name;
119
120{
121 {
122 "ParallelWorkerMain", ParallelWorkerMain
123 },
124 {
125 "ApplyLauncherMain", ApplyLauncherMain
126 },
127 {
128 "ApplyWorkerMain", ApplyWorkerMain
129 },
130 {
131 "ParallelApplyWorkerMain", ParallelApplyWorkerMain
132 },
133 {
134 "TablesyncWorkerMain", TablesyncWorkerMain
135 }
137
138/* Private functions. */
139static bgworker_main_type LookupBackgroundWorkerFunction(const char *libraryname, const char *funcname);
140
141
142/*
143 * Calculate shared memory needed.
144 */
145Size
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}
157
158/*
159 * Initialize shared memory.
160 */
161void
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}
215
216/*
217 * Search the postmaster's backend-private list of RegisteredBgWorker objects
218 * for the one that maps to the given slot number.
219 */
220static RegisteredBgWorker *
222{
223 dlist_iter iter;
224
226 {
228
229 rw = dlist_container(RegisteredBgWorker, rw_lnode, iter.cur);
230 if (rw->rw_shmem_slot == slotno)
231 return rw;
232 }
233
234 return NULL;
235}
236
237/*
238 * Notice changes to shared memory made by other backends.
239 * Accept new worker requests only if allow_new_workers is true.
240 *
241 * This code runs in the postmaster, so we must be very careful not to assume
242 * that shared memory contents are sane. Otherwise, a rogue backend could
243 * take out the postmaster.
244 */
245void
246BackgroundWorkerStateChange(bool allow_new_workers)
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}
417
418/*
419 * Forget about a background worker that's no longer needed.
420 *
421 * NOTE: The entry is unlinked from BackgroundWorkerList. If the caller is
422 * iterating through it, better use a mutable iterator!
423 *
424 * Caller is responsible for notifying bgw_notify_pid, if appropriate.
425 *
426 * This function must be invoked only in the postmaster.
427 */
428void
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}
454
455/*
456 * Report the PID of a newly-launched background worker in shared memory.
457 *
458 * This function should only be called from the postmaster.
459 */
460void
462{
464
467 slot->pid = rw->rw_pid;
468
469 if (rw->rw_worker.bgw_notify_pid != 0)
471}
472
473/*
474 * Report that the PID of a background worker is now zero because a
475 * previously-running background worker has exited.
476 *
477 * NOTE: The entry may be unlinked from BackgroundWorkerList. If the caller
478 * is iterating through it, better use a mutable iterator!
479 *
480 * This function should only be called from the postmaster.
481 */
482void
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}
507
508/*
509 * Cancel SIGUSR1 notifications for a PID belonging to an exiting backend.
510 *
511 * This function should only be called from the postmaster.
512 */
513void
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}
527
528/*
529 * Cancel any not-yet-started worker requests that have waiting processes.
530 *
531 * This is called during a normal ("smart" or "fast") database shutdown.
532 * After this point, no new background workers will be started, so anything
533 * that might be waiting for them needs to be kicked off its wait. We do
534 * that by canceling the bgworker registration entirely, which is perhaps
535 * overkill, but since we're shutting down it does not matter whether the
536 * registration record sticks around.
537 *
538 * This function should only be called from the postmaster.
539 */
540void
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}
567
568/*
569 * Reset background worker crash state.
570 *
571 * We assume that, after a crash-and-restart cycle, background workers without
572 * the never-restart flag should be restarted immediately, instead of waiting
573 * for bgw_restart_time to elapse. On the other hand, workers with that flag
574 * should be forgotten immediately, since we won't ever restart them.
575 *
576 * This function should only be called from the postmaster.
577 */
578void
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}
624
625/*
626 * Complain about the BackgroundWorker definition using error level elevel.
627 * Return true if it looks ok, false if not (unless elevel >= ERROR, in
628 * which case we won't return at all in the not-OK case).
629 */
630static bool
632{
633 /* sanity check for flags */
634
635 /*
636 * We used to support workers not connected to shared memory, but don't
637 * anymore. Thus this is a required flag now. We're not removing the flag
638 * for compatibility reasons and because the flag still provides some
639 * signal when reading code.
640 */
641 if (!(worker->bgw_flags & BGWORKER_SHMEM_ACCESS))
642 {
643 ereport(elevel,
644 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
645 errmsg("background worker \"%s\": background workers without shared memory access are not supported",
646 worker->bgw_name)));
647 return false;
648 }
649
651 {
653 {
654 ereport(elevel,
655 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
656 errmsg("background worker \"%s\": cannot request database access if starting at postmaster start",
657 worker->bgw_name)));
658 return false;
659 }
660
661 /* XXX other checks? */
662 }
663
664 if ((worker->bgw_restart_time < 0 &&
666 (worker->bgw_restart_time > USECS_PER_DAY / 1000))
667 {
668 ereport(elevel,
669 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
670 errmsg("background worker \"%s\": invalid restart interval",
671 worker->bgw_name)));
672 return false;
673 }
674
675 /*
676 * Parallel workers may not be configured for restart, because the
677 * parallel_register_count/parallel_terminate_count accounting can't
678 * handle parallel workers lasting through a crash-and-restart cycle.
679 */
680 if (worker->bgw_restart_time != BGW_NEVER_RESTART &&
681 (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0)
682 {
683 ereport(elevel,
684 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
685 errmsg("background worker \"%s\": parallel workers may not be configured for restart",
686 worker->bgw_name)));
687 return false;
688 }
689
690 /*
691 * If bgw_type is not filled in, use bgw_name.
692 */
693 if (strcmp(worker->bgw_type, "") == 0)
694 strcpy(worker->bgw_type, worker->bgw_name);
695
696 return true;
697}
698
699/*
700 * Standard SIGTERM handler for background workers
701 */
702static void
704{
705 sigprocmask(SIG_SETMASK, &BlockSig, NULL);
706
708 (errcode(ERRCODE_ADMIN_SHUTDOWN),
709 errmsg("terminating background worker \"%s\" due to administrator command",
711}
712
713/*
714 * Main entry point for background worker processes.
715 */
716void
717BackgroundWorkerMain(const void *startup_data, size_t startup_data_len)
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}
847
848/*
849 * Connect background worker to a database.
850 */
851void
853{
855 bits32 init_flags = 0; /* never honor session_preload_libraries */
856
857 /* ignore datallowconn and ACL_CONNECT? */
858 if (flags & BGWORKER_BYPASS_ALLOWCONN)
859 init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
860 /* ignore rolcanlogin? */
862 init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
863
864 /* XXX is this the right errcode? */
867 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
868 errmsg("database connection requirement not indicated during registration")));
869
870 InitPostgres(dbname, InvalidOid, /* database to connect to */
871 username, InvalidOid, /* role to connect as */
872 init_flags,
873 NULL); /* no out_dbname */
874
875 /* it had better not gotten out of "init" mode yet */
878 (errmsg("invalid processing mode in background worker")));
880}
881
882/*
883 * Connect background worker to a database using OIDs.
884 */
885void
887{
889 bits32 init_flags = 0; /* never honor session_preload_libraries */
890
891 /* ignore datallowconn and ACL_CONNECT? */
892 if (flags & BGWORKER_BYPASS_ALLOWCONN)
893 init_flags |= INIT_PG_OVERRIDE_ALLOW_CONNS;
894 /* ignore rolcanlogin? */
896 init_flags |= INIT_PG_OVERRIDE_ROLE_LOGIN;
897
898 /* XXX is this the right errcode? */
901 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
902 errmsg("database connection requirement not indicated during registration")));
903
904 InitPostgres(NULL, dboid, /* database to connect to */
905 NULL, useroid, /* role to connect as */
906 init_flags,
907 NULL); /* no out_dbname */
908
909 /* it had better not gotten out of "init" mode yet */
912 (errmsg("invalid processing mode in background worker")));
914}
915
916/*
917 * Block/unblock signals in a background worker
918 */
919void
921{
922 sigprocmask(SIG_SETMASK, &BlockSig, NULL);
923}
924
925void
927{
928 sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
929}
930
931/*
932 * Register a new static background worker.
933 *
934 * This can only be called directly from postmaster or in the _PG_init
935 * function of a module library that's loaded by shared_preload_libraries;
936 * otherwise it will have no effect.
937 */
938void
940{
942 static int numworkers = 0;
943
944 /*
945 * Static background workers can only be registered in the postmaster
946 * process.
947 */
949 {
950 /*
951 * In EXEC_BACKEND or single-user mode, we process
952 * shared_preload_libraries in backend processes too. We cannot
953 * register static background workers at that stage, but many
954 * libraries' _PG_init() functions don't distinguish whether they're
955 * being loaded in the postmaster or in a backend, they just check
956 * process_shared_preload_libraries_in_progress. It's a bit sloppy,
957 * but for historical reasons we tolerate it. In EXEC_BACKEND mode,
958 * the background workers should already have been registered when the
959 * library was loaded in postmaster.
960 */
962 return;
963 ereport(LOG,
964 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
965 errmsg("background worker \"%s\": must be registered in \"shared_preload_libraries\"",
966 worker->bgw_name)));
967 return;
968 }
969
970 /*
971 * Cannot register static background workers after calling
972 * BackgroundWorkerShmemInit().
973 */
974 if (BackgroundWorkerData != NULL)
975 elog(ERROR, "cannot register background worker \"%s\" after shmem init",
976 worker->bgw_name);
977
979 (errmsg_internal("registering background worker \"%s\"", worker->bgw_name)));
980
981 if (!SanityCheckBackgroundWorker(worker, LOG))
982 return;
983
984 if (worker->bgw_notify_pid != 0)
985 {
986 ereport(LOG,
987 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
988 errmsg("background worker \"%s\": only dynamic background workers can request notification",
989 worker->bgw_name)));
990 return;
991 }
992
993 /*
994 * Enforce maximum number of workers. Note this is overly restrictive: we
995 * could allow more non-shmem-connected workers, because these don't count
996 * towards the MAX_BACKENDS limit elsewhere. For now, it doesn't seem
997 * important to relax this restriction.
998 */
999 if (++numworkers > max_worker_processes)
1000 {
1001 ereport(LOG,
1002 (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
1003 errmsg("too many background workers"),
1004 errdetail_plural("Up to %d background worker can be registered with the current settings.",
1005 "Up to %d background workers can be registered with the current settings.",
1008 errhint("Consider increasing the configuration parameter \"%s\".", "max_worker_processes")));
1009 return;
1010 }
1011
1012 /*
1013 * Copy the registration data into the registered workers list.
1014 */
1016 sizeof(RegisteredBgWorker),
1018 if (rw == NULL)
1019 {
1020 ereport(LOG,
1021 (errcode(ERRCODE_OUT_OF_MEMORY),
1022 errmsg("out of memory")));
1023 return;
1024 }
1025
1026 rw->rw_worker = *worker;
1027 rw->rw_pid = 0;
1028 rw->rw_crashed_at = 0;
1029 rw->rw_terminate = false;
1030
1032}
1033
1034/*
1035 * Register a new background worker from a regular backend.
1036 *
1037 * Returns true on success and false on failure. Failure typically indicates
1038 * that no background worker slots are currently available.
1039 *
1040 * If handle != NULL, we'll set *handle to a pointer that can subsequently
1041 * be used as an argument to GetBackgroundWorkerPid(). The caller can
1042 * free this pointer using pfree(), if desired.
1043 */
1044bool
1046 BackgroundWorkerHandle **handle)
1047{
1048 int slotno;
1049 bool success = false;
1050 bool parallel;
1051 uint64 generation = 0;
1052
1053 /*
1054 * We can't register dynamic background workers from the postmaster. If
1055 * this is a standalone backend, we're the only process and can't start
1056 * any more. In a multi-process environment, it might be theoretically
1057 * possible, but we don't currently support it due to locking
1058 * considerations; see comments on the BackgroundWorkerSlot data
1059 * structure.
1060 */
1061 if (!IsUnderPostmaster)
1062 return false;
1063
1064 if (!SanityCheckBackgroundWorker(worker, ERROR))
1065 return false;
1066
1067 parallel = (worker->bgw_flags & BGWORKER_CLASS_PARALLEL) != 0;
1068
1069 LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1070
1071 /*
1072 * If this is a parallel worker, check whether there are already too many
1073 * parallel workers; if so, don't register another one. Our view of
1074 * parallel_terminate_count may be slightly stale, but that doesn't really
1075 * matter: we would have gotten the same result if we'd arrived here
1076 * slightly earlier anyway. There's no help for it, either, since the
1077 * postmaster must not take locks; a memory barrier wouldn't guarantee
1078 * anything useful.
1079 */
1083 {
1087 LWLockRelease(BackgroundWorkerLock);
1088 return false;
1089 }
1090
1091 /*
1092 * Look for an unused slot. If we find one, grab it.
1093 */
1094 for (slotno = 0; slotno < BackgroundWorkerData->total_slots; ++slotno)
1095 {
1097
1098 if (!slot->in_use)
1099 {
1100 memcpy(&slot->worker, worker, sizeof(BackgroundWorker));
1101 slot->pid = InvalidPid; /* indicates not started yet */
1102 slot->generation++;
1103 slot->terminate = false;
1104 generation = slot->generation;
1105 if (parallel)
1107
1108 /*
1109 * Make sure postmaster doesn't see the slot as in use before it
1110 * sees the new contents.
1111 */
1113
1114 slot->in_use = true;
1115 success = true;
1116 break;
1117 }
1118 }
1119
1120 LWLockRelease(BackgroundWorkerLock);
1121
1122 /* If we found a slot, tell the postmaster to notice the change. */
1123 if (success)
1125
1126 /*
1127 * If we found a slot and the user has provided a handle, initialize it.
1128 */
1129 if (success && handle)
1130 {
1131 *handle = palloc(sizeof(BackgroundWorkerHandle));
1132 (*handle)->slot = slotno;
1133 (*handle)->generation = generation;
1134 }
1135
1136 return success;
1137}
1138
1139/*
1140 * Get the PID of a dynamically-registered background worker.
1141 *
1142 * If the worker is determined to be running, the return value will be
1143 * BGWH_STARTED and *pidp will get the PID of the worker process. If the
1144 * postmaster has not yet attempted to start the worker, the return value will
1145 * be BGWH_NOT_YET_STARTED. Otherwise, the return value is BGWH_STOPPED.
1146 *
1147 * BGWH_STOPPED can indicate either that the worker is temporarily stopped
1148 * (because it is configured for automatic restart and exited non-zero),
1149 * or that the worker is permanently stopped (because it exited with exit
1150 * code 0, or was not configured for automatic restart), or even that the
1151 * worker was unregistered without ever starting (either because startup
1152 * failed and the worker is not configured for automatic restart, or because
1153 * TerminateBackgroundWorker was used before the worker was successfully
1154 * started).
1155 */
1158{
1160 pid_t pid;
1161
1162 Assert(handle->slot < max_worker_processes);
1163 slot = &BackgroundWorkerData->slot[handle->slot];
1164
1165 /*
1166 * We could probably arrange to synchronize access to data using memory
1167 * barriers only, but for now, let's just keep it simple and grab the
1168 * lock. It seems unlikely that there will be enough traffic here to
1169 * result in meaningful contention.
1170 */
1171 LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1172
1173 /*
1174 * The generation number can't be concurrently changed while we hold the
1175 * lock. The pid, which is updated by the postmaster, can change at any
1176 * time, but we assume such changes are atomic. So the value we read
1177 * won't be garbage, but it might be out of date by the time the caller
1178 * examines it (but that's unavoidable anyway).
1179 *
1180 * The in_use flag could be in the process of changing from true to false,
1181 * but if it is already false then it can't change further.
1182 */
1183 if (handle->generation != slot->generation || !slot->in_use)
1184 pid = 0;
1185 else
1186 pid = slot->pid;
1187
1188 /* All done. */
1189 LWLockRelease(BackgroundWorkerLock);
1190
1191 if (pid == 0)
1192 return BGWH_STOPPED;
1193 else if (pid == InvalidPid)
1194 return BGWH_NOT_YET_STARTED;
1195 *pidp = pid;
1196 return BGWH_STARTED;
1197}
1198
1199/*
1200 * Wait for a background worker to start up.
1201 *
1202 * This is like GetBackgroundWorkerPid(), except that if the worker has not
1203 * yet started, we wait for it to do so; thus, BGWH_NOT_YET_STARTED is never
1204 * returned. However, if the postmaster has died, we give up and return
1205 * BGWH_POSTMASTER_DIED, since it that case we know that startup will not
1206 * take place.
1207 *
1208 * The caller *must* have set our PID as the worker's bgw_notify_pid,
1209 * else we will not be awoken promptly when the worker's state changes.
1210 */
1213{
1214 BgwHandleStatus status;
1215 int rc;
1216
1217 for (;;)
1218 {
1219 pid_t pid;
1220
1222
1223 status = GetBackgroundWorkerPid(handle, &pid);
1224 if (status == BGWH_STARTED)
1225 *pidp = pid;
1226 if (status != BGWH_NOT_YET_STARTED)
1227 break;
1228
1229 rc = WaitLatch(MyLatch,
1231 WAIT_EVENT_BGWORKER_STARTUP);
1232
1233 if (rc & WL_POSTMASTER_DEATH)
1234 {
1235 status = BGWH_POSTMASTER_DIED;
1236 break;
1237 }
1238
1240 }
1241
1242 return status;
1243}
1244
1245/*
1246 * Wait for a background worker to stop.
1247 *
1248 * If the worker hasn't yet started, or is running, we wait for it to stop
1249 * and then return BGWH_STOPPED. However, if the postmaster has died, we give
1250 * up and return BGWH_POSTMASTER_DIED, because it's the postmaster that
1251 * notifies us when a worker's state changes.
1252 *
1253 * The caller *must* have set our PID as the worker's bgw_notify_pid,
1254 * else we will not be awoken promptly when the worker's state changes.
1255 */
1258{
1259 BgwHandleStatus status;
1260 int rc;
1261
1262 for (;;)
1263 {
1264 pid_t pid;
1265
1267
1268 status = GetBackgroundWorkerPid(handle, &pid);
1269 if (status == BGWH_STOPPED)
1270 break;
1271
1272 rc = WaitLatch(MyLatch,
1274 WAIT_EVENT_BGWORKER_SHUTDOWN);
1275
1276 if (rc & WL_POSTMASTER_DEATH)
1277 {
1278 status = BGWH_POSTMASTER_DIED;
1279 break;
1280 }
1281
1283 }
1284
1285 return status;
1286}
1287
1288/*
1289 * Instruct the postmaster to terminate a background worker.
1290 *
1291 * Note that it's safe to do this without regard to whether the worker is
1292 * still running, or even if the worker may already have exited and been
1293 * unregistered.
1294 */
1295void
1297{
1299 bool signal_postmaster = false;
1300
1301 Assert(handle->slot < max_worker_processes);
1302 slot = &BackgroundWorkerData->slot[handle->slot];
1303
1304 /* Set terminate flag in shared memory, unless slot has been reused. */
1305 LWLockAcquire(BackgroundWorkerLock, LW_EXCLUSIVE);
1306 if (handle->generation == slot->generation)
1307 {
1308 slot->terminate = true;
1309 signal_postmaster = true;
1310 }
1311 LWLockRelease(BackgroundWorkerLock);
1312
1313 /* Make sure the postmaster notices the change to shared memory. */
1314 if (signal_postmaster)
1316}
1317
1318/*
1319 * Look up (and possibly load) a bgworker entry point function.
1320 *
1321 * For functions contained in the core code, we use library name "postgres"
1322 * and consult the InternalBGWorkers array. External functions are
1323 * looked up, and loaded if necessary, using load_external_function().
1324 *
1325 * The point of this is to pass function names as strings across process
1326 * boundaries. We can't pass actual function addresses because of the
1327 * possibility that the function has been loaded at a different address
1328 * in a different process. This is obviously a hazard for functions in
1329 * loadable libraries, but it can happen even for functions in the core code
1330 * on platforms using EXEC_BACKEND (e.g., Windows).
1331 *
1332 * At some point it might be worthwhile to get rid of InternalBGWorkers[]
1333 * in favor of applying load_external_function() for core functions too;
1334 * but that raises portability issues that are not worth addressing now.
1335 */
1336static bgworker_main_type
1337LookupBackgroundWorkerFunction(const char *libraryname, const char *funcname)
1338{
1339 /*
1340 * If the function is to be loaded from postgres itself, search the
1341 * InternalBGWorkers array.
1342 */
1343 if (strcmp(libraryname, "postgres") == 0)
1344 {
1345 int i;
1346
1347 for (i = 0; i < lengthof(InternalBGWorkers); i++)
1348 {
1349 if (strcmp(InternalBGWorkers[i].fn_name, funcname) == 0)
1350 return InternalBGWorkers[i].fn_addr;
1351 }
1352
1353 /* We can only reach this by programming error. */
1354 elog(ERROR, "internal function \"%s\" not found", funcname);
1355 }
1356
1357 /* Otherwise load from external library. */
1358 return (bgworker_main_type)
1359 load_external_function(libraryname, funcname, true, NULL);
1360}
1361
1362/*
1363 * Given a PID, get the bgw_type of the background worker. Returns NULL if
1364 * not a valid background worker.
1365 *
1366 * The return value is in static memory belonging to this function, so it has
1367 * to be used before calling this function again. This is so that the caller
1368 * doesn't have to worry about the background worker locking protocol.
1369 */
1370const char *
1372{
1373 int slotno;
1374 bool found = false;
1375 static char result[BGW_MAXLEN];
1376
1377 LWLockAcquire(BackgroundWorkerLock, LW_SHARED);
1378
1379 for (slotno = 0; slotno < BackgroundWorkerData->total_slots; slotno++)
1380 {
1382
1383 if (slot->pid > 0 && slot->pid == pid)
1384 {
1385 strcpy(result, slot->worker.bgw_type);
1386 found = true;
1387 break;
1388 }
1389 }
1390
1391 LWLockRelease(BackgroundWorkerLock);
1392
1393 if (!found)
1394 return NULL;
1395
1396 return result;
1397}
void ParallelApplyWorkerMain(Datum main_arg)
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
#define pg_write_barrier()
Definition: atomics.h:157
void ParallelWorkerMain(Datum main_arg)
Definition: parallel.c:1292
sigset_t UnBlockSig
Definition: pqsignal.c:22
sigset_t BlockSig
Definition: pqsignal.c:23
void ApplyWorkerMain(Datum main_arg)
Definition: worker.c:4800
void RegisterBackgroundWorker(BackgroundWorker *worker)
Definition: bgworker.c:939
BgwHandleStatus WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1212
void BackgroundWorkerInitializeConnection(const char *dbname, const char *username, uint32 flags)
Definition: bgworker.c:852
static bool SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
Definition: bgworker.c:631
void ReportBackgroundWorkerPID(RegisteredBgWorker *rw)
Definition: bgworker.c:461
void TerminateBackgroundWorker(BackgroundWorkerHandle *handle)
Definition: bgworker.c:1296
static const struct @18 InternalBGWorkers[]
void ReportBackgroundWorkerExit(RegisteredBgWorker *rw)
Definition: bgworker.c:483
BgwHandleStatus WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
Definition: bgworker.c:1257
void ResetBackgroundWorkerCrashTimes(void)
Definition: bgworker.c:579
void BackgroundWorkerShmemInit(void)
Definition: bgworker.c:162
void BackgroundWorkerUnblockSignals(void)
Definition: bgworker.c:926
struct BackgroundWorkerSlot BackgroundWorkerSlot
void BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid, uint32 flags)
Definition: bgworker.c:886
void BackgroundWorkerBlockSignals(void)
Definition: bgworker.c:920
dlist_head BackgroundWorkerList
Definition: bgworker.c:40
void ForgetBackgroundWorker(RegisteredBgWorker *rw)
Definition: bgworker.c:429
const char * fn_name
Definition: bgworker.c:116
BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, pid_t *pidp)
Definition: bgworker.c:1157
static BackgroundWorkerArray * BackgroundWorkerData
Definition: bgworker.c:108
static RegisteredBgWorker * FindRegisteredWorkerBySlotNumber(int slotno)
Definition: bgworker.c:221
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
void BackgroundWorkerStopNotifications(pid_t pid)
Definition: bgworker.c:514
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:146
void BackgroundWorkerStateChange(bool allow_new_workers)
Definition: bgworker.c:246
const char * GetBackgroundWorkerTypeByPid(pid_t pid)
Definition: bgworker.c:1371
bool RegisterDynamicBackgroundWorker(BackgroundWorker *worker, BackgroundWorkerHandle **handle)
Definition: bgworker.c:1045
void BackgroundWorkerMain(const void *startup_data, size_t startup_data_len)
Definition: bgworker.c:717
bgworker_main_type fn_addr
Definition: bgworker.c:117
void ForgetUnstartedBackgroundWorkers(void)
Definition: bgworker.c:541
struct BackgroundWorkerArray BackgroundWorkerArray
#define BGW_NEVER_RESTART
Definition: bgworker.h:85
#define BGWORKER_BYPASS_ROLELOGINCHECK
Definition: bgworker.h:157
#define BGW_EXTRALEN
Definition: bgworker.h:87
#define BGWORKER_CLASS_PARALLEL
Definition: bgworker.h:68
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
@ BgWorkerStart_PostmasterStart
Definition: bgworker.h:79
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:60
#define BGWORKER_BYPASS_ALLOWCONN
Definition: bgworker.h:156
#define BGWORKER_SHMEM_ACCESS
Definition: bgworker.h:53
void(* bgworker_main_type)(Datum main_arg)
Definition: bgworker.h:72
#define BGW_MAXLEN
Definition: bgworker.h:86
#define MAX_PARALLEL_WORKER_LIMIT
#define SIGNAL_ARGS
Definition: c.h:1320
#define FLEXIBLE_ARRAY_MEMBER
Definition: c.h:434
uint32 bits32
Definition: c.h:511
uint64_t uint64
Definition: c.h:503
uint32_t uint32
Definition: c.h:502
#define lengthof(array)
Definition: c.h:759
size_t Size
Definition: c.h:576
#define USECS_PER_DAY
Definition: timestamp.h:131
void * load_external_function(const char *filename, const char *funcname, bool signalNotFound, void **filehandle)
Definition: dfmgr.c:93
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1157
void EmitErrorReport(void)
Definition: elog.c:1687
ErrorContextCallback * error_context_stack
Definition: elog.c:94
int errdetail_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1295
int errhint(const char *fmt,...)
Definition: elog.c:1317
int errcode(int sqlerrcode)
Definition: elog.c:853
int errmsg(const char *fmt,...)
Definition: elog.c:1070
sigjmp_buf * PG_exception_stack
Definition: elog.c:96
#define LOG
Definition: elog.h:31
#define FATAL
Definition: elog.h:41
#define DEBUG1
Definition: elog.h:30
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:225
#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
bool IsUnderPostmaster
Definition: globals.c:119
int max_parallel_workers
Definition: globals.c:144
bool IsPostmasterEnvironment
Definition: globals.c:118
struct Latch * MyLatch
Definition: globals.c:62
int max_worker_processes
Definition: globals.c:143
Assert(PointerIsAligned(start, uint64))
#define dlist_foreach(iter, lhead)
Definition: ilist.h:623
static void dlist_delete(dlist_node *node)
Definition: ilist.h:405
static void dlist_push_head(dlist_head *head, dlist_node *node)
Definition: ilist.h:347
#define dlist_foreach_modify(iter, lhead)
Definition: ilist.h:640
#define DLIST_STATIC_INIT(name)
Definition: ilist.h:281
#define dlist_container(type, membername, ptr)
Definition: ilist.h:593
#define funcname
Definition: indent_codes.h:69
static bool success
Definition: initdb.c:186
static char * username
Definition: initdb.c:153
void proc_exit(int code)
Definition: ipc.c:104
int i
Definition: isn.c:74
void ResetLatch(Latch *latch)
Definition: latch.c:372
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:172
void ApplyLauncherMain(Datum main_arg)
Definition: launcher.c:1119
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1179
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1899
@ LW_SHARED
Definition: lwlock.h:115
@ LW_EXCLUSIVE
Definition: lwlock.h:114
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:1181
void pfree(void *pointer)
Definition: mcxt.c:1524
MemoryContext TopMemoryContext
Definition: mcxt.c:149
void * palloc(Size size)
Definition: mcxt.c:1317
void * MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
Definition: mcxt.c:1238
MemoryContext PostmasterContext
Definition: mcxt.c:151
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:454
@ NormalProcessing
Definition: miscadmin.h:471
@ InitProcessing
Definition: miscadmin.h:470
#define GetProcessingMode()
Definition: miscadmin.h:480
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:133
#define IsInitProcessingMode()
Definition: miscadmin.h:477
#define SetProcessingMode(mode)
Definition: miscadmin.h:482
@ B_BG_WORKER
Definition: miscadmin.h:345
#define INIT_PG_OVERRIDE_ROLE_LOGIN
Definition: miscadmin.h:500
#define INIT_PG_OVERRIDE_ALLOW_CONNS
Definition: miscadmin.h:499
#define InvalidPid
Definition: miscadmin.h:32
BackendType MyBackendType
Definition: miscinit.c:64
bool process_shared_preload_libraries_in_progress
Definition: miscinit.c:1837
#define MAXPGPATH
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:165
@ PMSIGNAL_BACKGROUND_WORKER_CHANGE
Definition: pmsignal.h:40
#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
#define InvalidOid
Definition: postgres_ext.h:37
unsigned int Oid
Definition: postgres_ext.h:32
void BaseInit(void)
Definition: postinit.c:616
void InitPostgres(const char *in_dbname, Oid dboid, const char *username, Oid useroid, bits32 flags, char *out_dbname)
Definition: postinit.c:716
BackgroundWorker * MyBgworkerEntry
Definition: postmaster.c:199
bool PostmasterMarkPIDForWorkerNotify(int pid)
Definition: postmaster.c:4429
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:673
void init_ps_display(const char *fixed_part)
Definition: ps_status.c:269
Size add_size(Size s1, Size s2)
Definition: shmem.c:488
Size mul_size(Size s1, Size s2)
Definition: shmem.c:505
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:382
void pg_usleep(long microsec)
Definition: signal.c:53
void InitProcess(void)
Definition: proc.c:341
char * dbname
Definition: streamutil.c:49
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
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
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
pid_t bgw_notify_pid
Definition: bgworker.h:100
char bgw_library_name[MAXPGPATH]
Definition: bgworker.h:96
BackgroundWorker rw_worker
dlist_node * cur
Definition: ilist.h:179
dlist_node * cur
Definition: ilist.h:200
void TablesyncWorkerMain(Datum main_arg)
Definition: tablesync.c:1718
void InitializeTimeouts(void)
Definition: timeout.c:470
#define WL_LATCH_SET
Definition: waiteventset.h:34
#define WL_POSTMASTER_DEATH
Definition: waiteventset.h:38
#define SIGCHLD
Definition: win32_port.h:168
#define SIGHUP
Definition: win32_port.h:158
#define SIGPIPE
Definition: win32_port.h:163
#define kill(pid, sig)
Definition: win32_port.h:493
#define SIGUSR1
Definition: win32_port.h:170
#define SIGUSR2
Definition: win32_port.h:171