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parallel.c
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1 /*-------------------------------------------------------------------------
2  *
3  * parallel.c
4  * Infrastructure for launching parallel workers
5  *
6  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  * IDENTIFICATION
10  * src/backend/access/transam/parallel.c
11  *
12  *-------------------------------------------------------------------------
13  */
14 
15 #include "postgres.h"
16 
17 #include "access/parallel.h"
18 #include "access/session.h"
19 #include "access/xact.h"
20 #include "access/xlog.h"
21 #include "catalog/namespace.h"
22 #include "commands/async.h"
23 #include "executor/execParallel.h"
24 #include "libpq/libpq.h"
25 #include "libpq/pqformat.h"
26 #include "libpq/pqmq.h"
27 #include "miscadmin.h"
28 #include "optimizer/planmain.h"
29 #include "pgstat.h"
30 #include "storage/ipc.h"
31 #include "storage/sinval.h"
32 #include "storage/spin.h"
33 #include "tcop/tcopprot.h"
34 #include "utils/combocid.h"
35 #include "utils/guc.h"
36 #include "utils/inval.h"
37 #include "utils/memutils.h"
38 #include "utils/resowner.h"
39 #include "utils/snapmgr.h"
40 #include "utils/typcache.h"
41 
42 
43 /*
44  * We don't want to waste a lot of memory on an error queue which, most of
45  * the time, will process only a handful of small messages. However, it is
46  * desirable to make it large enough that a typical ErrorResponse can be sent
47  * without blocking. That way, a worker that errors out can write the whole
48  * message into the queue and terminate without waiting for the user backend.
49  */
50 #define PARALLEL_ERROR_QUEUE_SIZE 16384
51 
52 /* Magic number for parallel context TOC. */
53 #define PARALLEL_MAGIC 0x50477c7c
54 
55 /*
56  * Magic numbers for per-context parallel state sharing. Higher-level code
57  * should use smaller values, leaving these very large ones for use by this
58  * module.
59  */
60 #define PARALLEL_KEY_FIXED UINT64CONST(0xFFFFFFFFFFFF0001)
61 #define PARALLEL_KEY_ERROR_QUEUE UINT64CONST(0xFFFFFFFFFFFF0002)
62 #define PARALLEL_KEY_LIBRARY UINT64CONST(0xFFFFFFFFFFFF0003)
63 #define PARALLEL_KEY_GUC UINT64CONST(0xFFFFFFFFFFFF0004)
64 #define PARALLEL_KEY_COMBO_CID UINT64CONST(0xFFFFFFFFFFFF0005)
65 #define PARALLEL_KEY_TRANSACTION_SNAPSHOT UINT64CONST(0xFFFFFFFFFFFF0006)
66 #define PARALLEL_KEY_ACTIVE_SNAPSHOT UINT64CONST(0xFFFFFFFFFFFF0007)
67 #define PARALLEL_KEY_TRANSACTION_STATE UINT64CONST(0xFFFFFFFFFFFF0008)
68 #define PARALLEL_KEY_ENTRYPOINT UINT64CONST(0xFFFFFFFFFFFF0009)
69 #define PARALLEL_KEY_SESSION_DSM UINT64CONST(0xFFFFFFFFFFFF000A)
70 
71 /* Fixed-size parallel state. */
72 typedef struct FixedParallelState
73 {
74  /* Fixed-size state that workers must restore. */
86 
87  /* Mutex protects remaining fields. */
89 
90  /* Maximum XactLastRecEnd of any worker. */
93 
94 /*
95  * Our parallel worker number. We initialize this to -1, meaning that we are
96  * not a parallel worker. In parallel workers, it will be set to a value >= 0
97  * and < the number of workers before any user code is invoked; each parallel
98  * worker will get a different parallel worker number.
99  */
101 
102 /* Is there a parallel message pending which we need to receive? */
103 volatile bool ParallelMessagePending = false;
104 
105 /* Are we initializing a parallel worker? */
107 
108 /* Pointer to our fixed parallel state. */
110 
111 /* List of active parallel contexts. */
113 
114 /*
115  * List of internal parallel worker entry points. We need this for
116  * reasons explained in LookupParallelWorkerFunction(), below.
117  */
118 static const struct
119 {
120  const char *fn_name;
123 
124 {
125  {
126  "ParallelQueryMain", ParallelQueryMain
127  }
128 };
129 
130 /* Private functions. */
131 static void HandleParallelMessage(ParallelContext *pcxt, int i, StringInfo msg);
133 static parallel_worker_main_type LookupParallelWorkerFunction(const char *libraryname, const char *funcname);
134 
135 
136 /*
137  * Establish a new parallel context. This should be done after entering
138  * parallel mode, and (unless there is an error) the context should be
139  * destroyed before exiting the current subtransaction.
140  */
142 CreateParallelContext(const char *library_name, const char *function_name,
143  int nworkers)
144 {
145  MemoryContext oldcontext;
146  ParallelContext *pcxt;
147 
148  /* It is unsafe to create a parallel context if not in parallel mode. */
150 
151  /* Number of workers should be non-negative. */
152  Assert(nworkers >= 0);
153 
154  /*
155  * If dynamic shared memory is not available, we won't be able to use
156  * background workers.
157  */
159  nworkers = 0;
160 
161  /*
162  * If we are running under serializable isolation, we can't use parallel
163  * workers, at least not until somebody enhances that mechanism to be
164  * parallel-aware.
165  */
167  nworkers = 0;
168 
169  /* We might be running in a short-lived memory context. */
171 
172  /* Initialize a new ParallelContext. */
173  pcxt = palloc0(sizeof(ParallelContext));
175  pcxt->nworkers = nworkers;
176  pcxt->library_name = pstrdup(library_name);
177  pcxt->function_name = pstrdup(function_name);
180  dlist_push_head(&pcxt_list, &pcxt->node);
181 
182  /* Restore previous memory context. */
183  MemoryContextSwitchTo(oldcontext);
184 
185  return pcxt;
186 }
187 
188 /*
189  * Establish the dynamic shared memory segment for a parallel context and
190  * copy state and other bookkeeping information that will be needed by
191  * parallel workers into it.
192  */
193 void
195 {
196  MemoryContext oldcontext;
197  Size library_len = 0;
198  Size guc_len = 0;
199  Size combocidlen = 0;
200  Size tsnaplen = 0;
201  Size asnaplen = 0;
202  Size tstatelen = 0;
203  Size segsize = 0;
204  int i;
205  FixedParallelState *fps;
206  dsm_handle session_dsm_handle = DSM_HANDLE_INVALID;
207  Snapshot transaction_snapshot = GetTransactionSnapshot();
208  Snapshot active_snapshot = GetActiveSnapshot();
209 
210  /* We might be running in a very short-lived memory context. */
212 
213  /* Allow space to store the fixed-size parallel state. */
215  shm_toc_estimate_keys(&pcxt->estimator, 1);
216 
217  /*
218  * Normally, the user will have requested at least one worker process, but
219  * if by chance they have not, we can skip a bunch of things here.
220  */
221  if (pcxt->nworkers > 0)
222  {
223  /* Get (or create) the per-session DSM segment's handle. */
224  session_dsm_handle = GetSessionDsmHandle();
225 
226  /*
227  * If we weren't able to create a per-session DSM segment, then we can
228  * continue but we can't safely launch any workers because their
229  * record typmods would be incompatible so they couldn't exchange
230  * tuples.
231  */
232  if (session_dsm_handle == DSM_HANDLE_INVALID)
233  pcxt->nworkers = 0;
234  }
235 
236  if (pcxt->nworkers > 0)
237  {
238  /* Estimate space for various kinds of state sharing. */
239  library_len = EstimateLibraryStateSpace();
240  shm_toc_estimate_chunk(&pcxt->estimator, library_len);
241  guc_len = EstimateGUCStateSpace();
242  shm_toc_estimate_chunk(&pcxt->estimator, guc_len);
243  combocidlen = EstimateComboCIDStateSpace();
244  shm_toc_estimate_chunk(&pcxt->estimator, combocidlen);
245  tsnaplen = EstimateSnapshotSpace(transaction_snapshot);
246  shm_toc_estimate_chunk(&pcxt->estimator, tsnaplen);
247  asnaplen = EstimateSnapshotSpace(active_snapshot);
248  shm_toc_estimate_chunk(&pcxt->estimator, asnaplen);
249  tstatelen = EstimateTransactionStateSpace();
250  shm_toc_estimate_chunk(&pcxt->estimator, tstatelen);
252  /* If you add more chunks here, you probably need to add keys. */
253  shm_toc_estimate_keys(&pcxt->estimator, 7);
254 
255  /* Estimate space need for error queues. */
258  "parallel error queue size not buffer-aligned");
261  pcxt->nworkers));
262  shm_toc_estimate_keys(&pcxt->estimator, 1);
263 
264  /* Estimate how much we'll need for the entrypoint info. */
265  shm_toc_estimate_chunk(&pcxt->estimator, strlen(pcxt->library_name) +
266  strlen(pcxt->function_name) + 2);
267  shm_toc_estimate_keys(&pcxt->estimator, 1);
268  }
269 
270  /*
271  * Create DSM and initialize with new table of contents. But if the user
272  * didn't request any workers, then don't bother creating a dynamic shared
273  * memory segment; instead, just use backend-private memory.
274  *
275  * Also, if we can't create a dynamic shared memory segment because the
276  * maximum number of segments have already been created, then fall back to
277  * backend-private memory, and plan not to use any workers. We hope this
278  * won't happen very often, but it's better to abandon the use of
279  * parallelism than to fail outright.
280  */
281  segsize = shm_toc_estimate(&pcxt->estimator);
282  if (pcxt->nworkers > 0)
284  if (pcxt->seg != NULL)
286  dsm_segment_address(pcxt->seg),
287  segsize);
288  else
289  {
290  pcxt->nworkers = 0;
293  segsize);
294  }
295 
296  /* Initialize fixed-size state in shared memory. */
297  fps = (FixedParallelState *)
298  shm_toc_allocate(pcxt->toc, sizeof(FixedParallelState));
299  fps->database_id = MyDatabaseId;
309  SpinLockInit(&fps->mutex);
310  fps->last_xlog_end = 0;
312 
313  /* We can skip the rest of this if we're not budgeting for any workers. */
314  if (pcxt->nworkers > 0)
315  {
316  char *libraryspace;
317  char *gucspace;
318  char *combocidspace;
319  char *tsnapspace;
320  char *asnapspace;
321  char *tstatespace;
322  char *error_queue_space;
323  char *session_dsm_handle_space;
324  char *entrypointstate;
325  Size lnamelen;
326 
327  /* Serialize shared libraries we have loaded. */
328  libraryspace = shm_toc_allocate(pcxt->toc, library_len);
329  SerializeLibraryState(library_len, libraryspace);
330  shm_toc_insert(pcxt->toc, PARALLEL_KEY_LIBRARY, libraryspace);
331 
332  /* Serialize GUC settings. */
333  gucspace = shm_toc_allocate(pcxt->toc, guc_len);
334  SerializeGUCState(guc_len, gucspace);
335  shm_toc_insert(pcxt->toc, PARALLEL_KEY_GUC, gucspace);
336 
337  /* Serialize combo CID state. */
338  combocidspace = shm_toc_allocate(pcxt->toc, combocidlen);
339  SerializeComboCIDState(combocidlen, combocidspace);
340  shm_toc_insert(pcxt->toc, PARALLEL_KEY_COMBO_CID, combocidspace);
341 
342  /* Serialize transaction snapshot and active snapshot. */
343  tsnapspace = shm_toc_allocate(pcxt->toc, tsnaplen);
344  SerializeSnapshot(transaction_snapshot, tsnapspace);
346  tsnapspace);
347  asnapspace = shm_toc_allocate(pcxt->toc, asnaplen);
348  SerializeSnapshot(active_snapshot, asnapspace);
349  shm_toc_insert(pcxt->toc, PARALLEL_KEY_ACTIVE_SNAPSHOT, asnapspace);
350 
351  /* Provide the handle for per-session segment. */
352  session_dsm_handle_space = shm_toc_allocate(pcxt->toc,
353  sizeof(dsm_handle));
354  *(dsm_handle *) session_dsm_handle_space = session_dsm_handle;
356  session_dsm_handle_space);
357 
358  /* Serialize transaction state. */
359  tstatespace = shm_toc_allocate(pcxt->toc, tstatelen);
360  SerializeTransactionState(tstatelen, tstatespace);
362 
363  /* Allocate space for worker information. */
364  pcxt->worker = palloc0(sizeof(ParallelWorkerInfo) * pcxt->nworkers);
365 
366  /*
367  * Establish error queues in dynamic shared memory.
368  *
369  * These queues should be used only for transmitting ErrorResponse,
370  * NoticeResponse, and NotifyResponse protocol messages. Tuple data
371  * should be transmitted via separate (possibly larger?) queues.
372  */
373  error_queue_space =
374  shm_toc_allocate(pcxt->toc,
376  pcxt->nworkers));
377  for (i = 0; i < pcxt->nworkers; ++i)
378  {
379  char *start;
380  shm_mq *mq;
381 
382  start = error_queue_space + i * PARALLEL_ERROR_QUEUE_SIZE;
383  mq = shm_mq_create(start, PARALLEL_ERROR_QUEUE_SIZE);
385  pcxt->worker[i].error_mqh = shm_mq_attach(mq, pcxt->seg, NULL);
386  }
387  shm_toc_insert(pcxt->toc, PARALLEL_KEY_ERROR_QUEUE, error_queue_space);
388 
389  /*
390  * Serialize entrypoint information. It's unsafe to pass function
391  * pointers across processes, as the function pointer may be different
392  * in each process in EXEC_BACKEND builds, so we always pass library
393  * and function name. (We use library name "postgres" for functions
394  * in the core backend.)
395  */
396  lnamelen = strlen(pcxt->library_name);
397  entrypointstate = shm_toc_allocate(pcxt->toc, lnamelen +
398  strlen(pcxt->function_name) + 2);
399  strcpy(entrypointstate, pcxt->library_name);
400  strcpy(entrypointstate + lnamelen + 1, pcxt->function_name);
401  shm_toc_insert(pcxt->toc, PARALLEL_KEY_ENTRYPOINT, entrypointstate);
402  }
403 
404  /* Restore previous memory context. */
405  MemoryContextSwitchTo(oldcontext);
406 }
407 
408 /*
409  * Reinitialize the dynamic shared memory segment for a parallel context such
410  * that we could launch workers for it again.
411  */
412 void
414 {
415  FixedParallelState *fps;
416  char *error_queue_space;
417  int i;
418 
419  /* Wait for any old workers to exit. */
420  if (pcxt->nworkers_launched > 0)
421  {
424  pcxt->nworkers_launched = 0;
425  }
426 
427  /* Reset a few bits of fixed parallel state to a clean state. */
428  fps = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_FIXED, false);
429  fps->last_xlog_end = 0;
430 
431  /* Recreate error queues (if they exist). */
432  error_queue_space =
434  Assert(pcxt->nworkers == 0 || error_queue_space != NULL);
435  for (i = 0; i < pcxt->nworkers; ++i)
436  {
437  char *start;
438  shm_mq *mq;
439 
440  start = error_queue_space + i * PARALLEL_ERROR_QUEUE_SIZE;
441  mq = shm_mq_create(start, PARALLEL_ERROR_QUEUE_SIZE);
443  pcxt->worker[i].error_mqh = shm_mq_attach(mq, pcxt->seg, NULL);
444  }
445 }
446 
447 /*
448  * Launch parallel workers.
449  */
450 void
452 {
453  MemoryContext oldcontext;
454  BackgroundWorker worker;
455  int i;
456  bool any_registrations_failed = false;
457 
458  /* Skip this if we have no workers. */
459  if (pcxt->nworkers == 0)
460  return;
461 
462  /* We need to be a lock group leader. */
464 
465  /* If we do have workers, we'd better have a DSM segment. */
466  Assert(pcxt->seg != NULL);
467 
468  /* We might be running in a short-lived memory context. */
470 
471  /* Configure a worker. */
472  memset(&worker, 0, sizeof(worker));
473  snprintf(worker.bgw_name, BGW_MAXLEN, "parallel worker for PID %d",
474  MyProcPid);
475  snprintf(worker.bgw_type, BGW_MAXLEN, "parallel worker");
476  worker.bgw_flags =
481  sprintf(worker.bgw_library_name, "postgres");
482  sprintf(worker.bgw_function_name, "ParallelWorkerMain");
484  worker.bgw_notify_pid = MyProcPid;
485 
486  /*
487  * Start workers.
488  *
489  * The caller must be able to tolerate ending up with fewer workers than
490  * expected, so there is no need to throw an error here if registration
491  * fails. It wouldn't help much anyway, because registering the worker in
492  * no way guarantees that it will start up and initialize successfully.
493  */
494  for (i = 0; i < pcxt->nworkers; ++i)
495  {
496  memcpy(worker.bgw_extra, &i, sizeof(int));
497  if (!any_registrations_failed &&
499  &pcxt->worker[i].bgwhandle))
500  {
502  pcxt->worker[i].bgwhandle);
503  pcxt->nworkers_launched++;
504  }
505  else
506  {
507  /*
508  * If we weren't able to register the worker, then we've bumped up
509  * against the max_worker_processes limit, and future
510  * registrations will probably fail too, so arrange to skip them.
511  * But we still have to execute this code for the remaining slots
512  * to make sure that we forget about the error queues we budgeted
513  * for those workers. Otherwise, we'll wait for them to start,
514  * but they never will.
515  */
516  any_registrations_failed = true;
517  pcxt->worker[i].bgwhandle = NULL;
518  shm_mq_detach(pcxt->worker[i].error_mqh);
519  pcxt->worker[i].error_mqh = NULL;
520  }
521  }
522 
523  /* Restore previous memory context. */
524  MemoryContextSwitchTo(oldcontext);
525 }
526 
527 /*
528  * Wait for all workers to finish computing.
529  *
530  * Even if the parallel operation seems to have completed successfully, it's
531  * important to call this function afterwards. We must not miss any errors
532  * the workers may have thrown during the parallel operation, or any that they
533  * may yet throw while shutting down.
534  *
535  * Also, we want to update our notion of XactLastRecEnd based on worker
536  * feedback.
537  */
538 void
540 {
541  for (;;)
542  {
543  bool anyone_alive = false;
544  int i;
545 
546  /*
547  * This will process any parallel messages that are pending, which may
548  * change the outcome of the loop that follows. It may also throw an
549  * error propagated from a worker.
550  */
552 
553  for (i = 0; i < pcxt->nworkers_launched; ++i)
554  {
555  if (pcxt->worker[i].error_mqh != NULL)
556  {
557  anyone_alive = true;
558  break;
559  }
560  }
561 
562  if (!anyone_alive)
563  break;
564 
568  }
569 
570  if (pcxt->toc != NULL)
571  {
572  FixedParallelState *fps;
573 
574  fps = shm_toc_lookup(pcxt->toc, PARALLEL_KEY_FIXED, false);
575  if (fps->last_xlog_end > XactLastRecEnd)
577  }
578 }
579 
580 /*
581  * Wait for all workers to exit.
582  *
583  * This function ensures that workers have been completely shutdown. The
584  * difference between WaitForParallelWorkersToFinish and this function is
585  * that former just ensures that last message sent by worker backend is
586  * received by master backend whereas this ensures the complete shutdown.
587  */
588 static void
590 {
591  int i;
592 
593  /* Wait until the workers actually die. */
594  for (i = 0; i < pcxt->nworkers_launched; ++i)
595  {
597 
598  if (pcxt->worker == NULL || pcxt->worker[i].bgwhandle == NULL)
599  continue;
600 
602 
603  /*
604  * If the postmaster kicked the bucket, we have no chance of cleaning
605  * up safely -- we won't be able to tell when our workers are actually
606  * dead. This doesn't necessitate a PANIC since they will all abort
607  * eventually, but we can't safely continue this session.
608  */
609  if (status == BGWH_POSTMASTER_DIED)
610  ereport(FATAL,
611  (errcode(ERRCODE_ADMIN_SHUTDOWN),
612  errmsg("postmaster exited during a parallel transaction")));
613 
614  /* Release memory. */
615  pfree(pcxt->worker[i].bgwhandle);
616  pcxt->worker[i].bgwhandle = NULL;
617  }
618 }
619 
620 /*
621  * Destroy a parallel context.
622  *
623  * If expecting a clean exit, you should use WaitForParallelWorkersToFinish()
624  * first, before calling this function. When this function is invoked, any
625  * remaining workers are forcibly killed; the dynamic shared memory segment
626  * is unmapped; and we then wait (uninterruptibly) for the workers to exit.
627  */
628 void
630 {
631  int i;
632 
633  /*
634  * Be careful about order of operations here! We remove the parallel
635  * context from the list before we do anything else; otherwise, if an
636  * error occurs during a subsequent step, we might try to nuke it again
637  * from AtEOXact_Parallel or AtEOSubXact_Parallel.
638  */
639  dlist_delete(&pcxt->node);
640 
641  /* Kill each worker in turn, and forget their error queues. */
642  if (pcxt->worker != NULL)
643  {
644  for (i = 0; i < pcxt->nworkers_launched; ++i)
645  {
646  if (pcxt->worker[i].error_mqh != NULL)
647  {
649 
650  shm_mq_detach(pcxt->worker[i].error_mqh);
651  pcxt->worker[i].error_mqh = NULL;
652  }
653  }
654  }
655 
656  /*
657  * If we have allocated a shared memory segment, detach it. This will
658  * implicitly detach the error queues, and any other shared memory queues,
659  * stored there.
660  */
661  if (pcxt->seg != NULL)
662  {
663  dsm_detach(pcxt->seg);
664  pcxt->seg = NULL;
665  }
666 
667  /*
668  * If this parallel context is actually in backend-private memory rather
669  * than shared memory, free that memory instead.
670  */
671  if (pcxt->private_memory != NULL)
672  {
673  pfree(pcxt->private_memory);
674  pcxt->private_memory = NULL;
675  }
676 
677  /*
678  * We can't finish transaction commit or abort until all of the workers
679  * have exited. This means, in particular, that we can't respond to
680  * interrupts at this stage.
681  */
682  HOLD_INTERRUPTS();
685 
686  /* Free the worker array itself. */
687  if (pcxt->worker != NULL)
688  {
689  pfree(pcxt->worker);
690  pcxt->worker = NULL;
691  }
692 
693  /* Free memory. */
694  pfree(pcxt->library_name);
695  pfree(pcxt->function_name);
696  pfree(pcxt);
697 }
698 
699 /*
700  * Are there any parallel contexts currently active?
701  */
702 bool
704 {
705  return !dlist_is_empty(&pcxt_list);
706 }
707 
708 /*
709  * Handle receipt of an interrupt indicating a parallel worker message.
710  *
711  * Note: this is called within a signal handler! All we can do is set
712  * a flag that will cause the next CHECK_FOR_INTERRUPTS() to invoke
713  * HandleParallelMessages().
714  */
715 void
717 {
718  InterruptPending = true;
719  ParallelMessagePending = true;
720  SetLatch(MyLatch);
721 }
722 
723 /*
724  * Handle any queued protocol messages received from parallel workers.
725  */
726 void
728 {
729  dlist_iter iter;
730  MemoryContext oldcontext;
731 
732  static MemoryContext hpm_context = NULL;
733 
734  /*
735  * This is invoked from ProcessInterrupts(), and since some of the
736  * functions it calls contain CHECK_FOR_INTERRUPTS(), there is a potential
737  * for recursive calls if more signals are received while this runs. It's
738  * unclear that recursive entry would be safe, and it doesn't seem useful
739  * even if it is safe, so let's block interrupts until done.
740  */
741  HOLD_INTERRUPTS();
742 
743  /*
744  * Moreover, CurrentMemoryContext might be pointing almost anywhere. We
745  * don't want to risk leaking data into long-lived contexts, so let's do
746  * our work here in a private context that we can reset on each use.
747  */
748  if (hpm_context == NULL) /* first time through? */
750  "HandleParallelMessages",
752  else
753  MemoryContextReset(hpm_context);
754 
755  oldcontext = MemoryContextSwitchTo(hpm_context);
756 
757  /* OK to process messages. Reset the flag saying there are more to do. */
758  ParallelMessagePending = false;
759 
760  dlist_foreach(iter, &pcxt_list)
761  {
762  ParallelContext *pcxt;
763  int i;
764 
765  pcxt = dlist_container(ParallelContext, node, iter.cur);
766  if (pcxt->worker == NULL)
767  continue;
768 
769  for (i = 0; i < pcxt->nworkers_launched; ++i)
770  {
771  /*
772  * Read as many messages as we can from each worker, but stop when
773  * either (1) the worker's error queue goes away, which can happen
774  * if we receive a Terminate message from the worker; or (2) no
775  * more messages can be read from the worker without blocking.
776  */
777  while (pcxt->worker[i].error_mqh != NULL)
778  {
779  shm_mq_result res;
780  Size nbytes;
781  void *data;
782 
783  res = shm_mq_receive(pcxt->worker[i].error_mqh, &nbytes,
784  &data, true);
785  if (res == SHM_MQ_WOULD_BLOCK)
786  break;
787  else if (res == SHM_MQ_SUCCESS)
788  {
789  StringInfoData msg;
790 
791  initStringInfo(&msg);
792  appendBinaryStringInfo(&msg, data, nbytes);
793  HandleParallelMessage(pcxt, i, &msg);
794  pfree(msg.data);
795  }
796  else
797  ereport(ERROR,
798  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
799  errmsg("lost connection to parallel worker")));
800  }
801  }
802  }
803 
804  MemoryContextSwitchTo(oldcontext);
805 
806  /* Might as well clear the context on our way out */
807  MemoryContextReset(hpm_context);
808 
810 }
811 
812 /*
813  * Handle a single protocol message received from a single parallel worker.
814  */
815 static void
817 {
818  char msgtype;
819 
820  msgtype = pq_getmsgbyte(msg);
821 
822  switch (msgtype)
823  {
824  case 'K': /* BackendKeyData */
825  {
826  int32 pid = pq_getmsgint(msg, 4);
827 
828  (void) pq_getmsgint(msg, 4); /* discard cancel key */
829  (void) pq_getmsgend(msg);
830  pcxt->worker[i].pid = pid;
831  break;
832  }
833 
834  case 'E': /* ErrorResponse */
835  case 'N': /* NoticeResponse */
836  {
837  ErrorData edata;
838  ErrorContextCallback *save_error_context_stack;
839 
840  /* Parse ErrorResponse or NoticeResponse. */
841  pq_parse_errornotice(msg, &edata);
842 
843  /* Death of a worker isn't enough justification for suicide. */
844  edata.elevel = Min(edata.elevel, ERROR);
845 
846  /*
847  * If desired, add a context line to show that this is a
848  * message propagated from a parallel worker. Otherwise, it
849  * can sometimes be confusing to understand what actually
850  * happened. (We don't do this in FORCE_PARALLEL_REGRESS mode
851  * because it causes test-result instability depending on
852  * whether a parallel worker is actually used or not.)
853  */
855  {
856  if (edata.context)
857  edata.context = psprintf("%s\n%s", edata.context,
858  _("parallel worker"));
859  else
860  edata.context = pstrdup(_("parallel worker"));
861  }
862 
863  /*
864  * Context beyond that should use the error context callbacks
865  * that were in effect when the ParallelContext was created,
866  * not the current ones.
867  */
868  save_error_context_stack = error_context_stack;
870 
871  /* Rethrow error or print notice. */
872  ThrowErrorData(&edata);
873 
874  /* Not an error, so restore previous context stack. */
875  error_context_stack = save_error_context_stack;
876 
877  break;
878  }
879 
880  case 'A': /* NotifyResponse */
881  {
882  /* Propagate NotifyResponse. */
883  int32 pid;
884  const char *channel;
885  const char *payload;
886 
887  pid = pq_getmsgint(msg, 4);
888  channel = pq_getmsgrawstring(msg);
889  payload = pq_getmsgrawstring(msg);
890  pq_endmessage(msg);
891 
892  NotifyMyFrontEnd(channel, payload, pid);
893 
894  break;
895  }
896 
897  case 'X': /* Terminate, indicating clean exit */
898  {
899  shm_mq_detach(pcxt->worker[i].error_mqh);
900  pcxt->worker[i].error_mqh = NULL;
901  break;
902  }
903 
904  default:
905  {
906  elog(ERROR, "unrecognized message type received from parallel worker: %c (message length %d bytes)",
907  msgtype, msg->len);
908  }
909  }
910 }
911 
912 /*
913  * End-of-subtransaction cleanup for parallel contexts.
914  *
915  * Currently, it's forbidden to enter or leave a subtransaction while
916  * parallel mode is in effect, so we could just blow away everything. But
917  * we may want to relax that restriction in the future, so this code
918  * contemplates that there may be multiple subtransaction IDs in pcxt_list.
919  */
920 void
921 AtEOSubXact_Parallel(bool isCommit, SubTransactionId mySubId)
922 {
923  while (!dlist_is_empty(&pcxt_list))
924  {
925  ParallelContext *pcxt;
926 
927  pcxt = dlist_head_element(ParallelContext, node, &pcxt_list);
928  if (pcxt->subid != mySubId)
929  break;
930  if (isCommit)
931  elog(WARNING, "leaked parallel context");
933  }
934 }
935 
936 /*
937  * End-of-transaction cleanup for parallel contexts.
938  */
939 void
940 AtEOXact_Parallel(bool isCommit)
941 {
942  while (!dlist_is_empty(&pcxt_list))
943  {
944  ParallelContext *pcxt;
945 
946  pcxt = dlist_head_element(ParallelContext, node, &pcxt_list);
947  if (isCommit)
948  elog(WARNING, "leaked parallel context");
950  }
951 }
952 
953 /*
954  * Main entrypoint for parallel workers.
955  */
956 void
958 {
959  dsm_segment *seg;
960  shm_toc *toc;
961  FixedParallelState *fps;
962  char *error_queue_space;
963  shm_mq *mq;
964  shm_mq_handle *mqh;
965  char *libraryspace;
966  char *entrypointstate;
967  char *library_name;
968  char *function_name;
970  char *gucspace;
971  char *combocidspace;
972  char *tsnapspace;
973  char *asnapspace;
974  char *tstatespace;
975  StringInfoData msgbuf;
976  char *session_dsm_handle_space;
977 
978  /* Set flag to indicate that we're initializing a parallel worker. */
980 
981  /* Establish signal handlers. */
982  pqsignal(SIGTERM, die);
984 
985  /* Determine and set our parallel worker number. */
987  memcpy(&ParallelWorkerNumber, MyBgworkerEntry->bgw_extra, sizeof(int));
988 
989  /* Set up a memory context and resource owner. */
990  Assert(CurrentResourceOwner == NULL);
991  CurrentResourceOwner = ResourceOwnerCreate(NULL, "parallel toplevel");
993  "Parallel worker",
995 
996  /*
997  * Now that we have a resource owner, we can attach to the dynamic shared
998  * memory segment and read the table of contents.
999  */
1000  seg = dsm_attach(DatumGetUInt32(main_arg));
1001  if (seg == NULL)
1002  ereport(ERROR,
1003  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1004  errmsg("could not map dynamic shared memory segment")));
1006  if (toc == NULL)
1007  ereport(ERROR,
1008  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1009  errmsg("invalid magic number in dynamic shared memory segment")));
1010 
1011  /* Look up fixed parallel state. */
1012  fps = shm_toc_lookup(toc, PARALLEL_KEY_FIXED, false);
1013  MyFixedParallelState = fps;
1014 
1015  /*
1016  * Now that we have a worker number, we can find and attach to the error
1017  * queue provided for us. That's good, because until we do that, any
1018  * errors that happen here will not be reported back to the process that
1019  * requested that this worker be launched.
1020  */
1021  error_queue_space = shm_toc_lookup(toc, PARALLEL_KEY_ERROR_QUEUE, false);
1022  mq = (shm_mq *) (error_queue_space +
1025  mqh = shm_mq_attach(mq, seg, NULL);
1026  pq_redirect_to_shm_mq(seg, mqh);
1029 
1030  /*
1031  * Send a BackendKeyData message to the process that initiated parallelism
1032  * so that it has access to our PID before it receives any other messages
1033  * from us. Our cancel key is sent, too, since that's the way the
1034  * protocol message is defined, but it won't actually be used for anything
1035  * in this case.
1036  */
1037  pq_beginmessage(&msgbuf, 'K');
1038  pq_sendint32(&msgbuf, (int32) MyProcPid);
1039  pq_sendint32(&msgbuf, (int32) MyCancelKey);
1040  pq_endmessage(&msgbuf);
1041 
1042  /*
1043  * Hooray! Primary initialization is complete. Now, we need to set up our
1044  * backend-local state to match the original backend.
1045  */
1046 
1047  /*
1048  * Join locking group. We must do this before anything that could try to
1049  * acquire a heavyweight lock, because any heavyweight locks acquired to
1050  * this point could block either directly against the parallel group
1051  * leader or against some process which in turn waits for a lock that
1052  * conflicts with the parallel group leader, causing an undetected
1053  * deadlock. (If we can't join the lock group, the leader has gone away,
1054  * so just exit quietly.)
1055  */
1057  fps->parallel_master_pid))
1058  return;
1059 
1060  /*
1061  * Load libraries that were loaded by original backend. We want to do
1062  * this before restoring GUCs, because the libraries might define custom
1063  * variables.
1064  */
1065  libraryspace = shm_toc_lookup(toc, PARALLEL_KEY_LIBRARY, false);
1066  RestoreLibraryState(libraryspace);
1067 
1068  /*
1069  * Identify the entry point to be called. In theory this could result in
1070  * loading an additional library, though most likely the entry point is in
1071  * the core backend or in a library we just loaded.
1072  */
1073  entrypointstate = shm_toc_lookup(toc, PARALLEL_KEY_ENTRYPOINT, false);
1074  library_name = entrypointstate;
1075  function_name = entrypointstate + strlen(library_name) + 1;
1076 
1077  entrypt = LookupParallelWorkerFunction(library_name, function_name);
1078 
1079  /* Restore database connection. */
1081  fps->authenticated_user_id);
1082 
1083  /*
1084  * Set the client encoding to the database encoding, since that is what
1085  * the leader will expect.
1086  */
1088 
1089  /* Restore GUC values from launching backend. */
1090  gucspace = shm_toc_lookup(toc, PARALLEL_KEY_GUC, false);
1092  RestoreGUCState(gucspace);
1094 
1095  /* Crank up a transaction state appropriate to a parallel worker. */
1096  tstatespace = shm_toc_lookup(toc, PARALLEL_KEY_TRANSACTION_STATE, false);
1097  StartParallelWorkerTransaction(tstatespace);
1098 
1099  /* Restore combo CID state. */
1100  combocidspace = shm_toc_lookup(toc, PARALLEL_KEY_COMBO_CID, false);
1101  RestoreComboCIDState(combocidspace);
1102 
1103  /* Attach to the per-session DSM segment and contained objects. */
1104  session_dsm_handle_space =
1106  AttachSession(*(dsm_handle *) session_dsm_handle_space);
1107 
1108  /* Restore transaction snapshot. */
1109  tsnapspace = shm_toc_lookup(toc, PARALLEL_KEY_TRANSACTION_SNAPSHOT, false);
1111  fps->parallel_master_pgproc);
1112 
1113  /* Restore active snapshot. */
1114  asnapspace = shm_toc_lookup(toc, PARALLEL_KEY_ACTIVE_SNAPSHOT, false);
1115  PushActiveSnapshot(RestoreSnapshot(asnapspace));
1116 
1117  /*
1118  * We've changed which tuples we can see, and must therefore invalidate
1119  * system caches.
1120  */
1122 
1123  /*
1124  * Restore current role id. Skip verifying whether session user is
1125  * allowed to become this role and blindly restore the leader's state for
1126  * current role.
1127  */
1129 
1130  /* Restore user ID and security context. */
1132 
1133  /* Restore temp-namespace state to ensure search path matches leader's. */
1136 
1137  /* Set ParallelMasterBackendId so we know how to address temp relations. */
1139 
1140  /*
1141  * We've initialized all of our state now; nothing should change
1142  * hereafter.
1143  */
1146 
1147  /*
1148  * Time to do the real work: invoke the caller-supplied code.
1149  */
1150  entrypt(seg, toc);
1151 
1152  /* Must exit parallel mode to pop active snapshot. */
1153  ExitParallelMode();
1154 
1155  /* Must pop active snapshot so resowner.c doesn't complain. */
1157 
1158  /* Shut down the parallel-worker transaction. */
1160 
1161  /* Detach from the per-session DSM segment. */
1162  DetachSession();
1163 
1164  /* Report success. */
1165  pq_putmessage('X', NULL, 0);
1166 }
1167 
1168 /*
1169  * Update shared memory with the ending location of the last WAL record we
1170  * wrote, if it's greater than the value already stored there.
1171  */
1172 void
1174 {
1176 
1177  Assert(fps != NULL);
1178  SpinLockAcquire(&fps->mutex);
1179  if (fps->last_xlog_end < last_xlog_end)
1181  SpinLockRelease(&fps->mutex);
1182 }
1183 
1184 /*
1185  * Look up (and possibly load) a parallel worker entry point function.
1186  *
1187  * For functions contained in the core code, we use library name "postgres"
1188  * and consult the InternalParallelWorkers array. External functions are
1189  * looked up, and loaded if necessary, using load_external_function().
1190  *
1191  * The point of this is to pass function names as strings across process
1192  * boundaries. We can't pass actual function addresses because of the
1193  * possibility that the function has been loaded at a different address
1194  * in a different process. This is obviously a hazard for functions in
1195  * loadable libraries, but it can happen even for functions in the core code
1196  * on platforms using EXEC_BACKEND (e.g., Windows).
1197  *
1198  * At some point it might be worthwhile to get rid of InternalParallelWorkers[]
1199  * in favor of applying load_external_function() for core functions too;
1200  * but that raises portability issues that are not worth addressing now.
1201  */
1203 LookupParallelWorkerFunction(const char *libraryname, const char *funcname)
1204 {
1205  /*
1206  * If the function is to be loaded from postgres itself, search the
1207  * InternalParallelWorkers array.
1208  */
1209  if (strcmp(libraryname, "postgres") == 0)
1210  {
1211  int i;
1212 
1213  for (i = 0; i < lengthof(InternalParallelWorkers); i++)
1214  {
1215  if (strcmp(InternalParallelWorkers[i].fn_name, funcname) == 0)
1216  return InternalParallelWorkers[i].fn_addr;
1217  }
1218 
1219  /* We can only reach this by programming error. */
1220  elog(ERROR, "internal function \"%s\" not found", funcname);
1221  }
1222 
1223  /* Otherwise load from external library. */
1224  return (parallel_worker_main_type)
1225  load_external_function(libraryname, funcname, true, NULL);
1226 }
char bgw_extra[BGW_EXTRALEN]
Definition: bgworker.h:98
#define DatumGetUInt32(X)
Definition: postgres.h:492
int slock_t
Definition: s_lock.h:912
#define PARALLEL_ERROR_QUEUE_SIZE
Definition: parallel.c:50
static const struct @21 InternalParallelWorkers[]
shm_toc * shm_toc_create(uint64 magic, void *address, Size nbytes)
Definition: shm_toc.c:40
int MyProcPid
Definition: globals.c:39
BackendId MyBackendId
Definition: globals.c:73
Snapshot RestoreSnapshot(char *start_address)
Definition: snapmgr.c:2127
MemoryContext TopTransactionContext
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uint32 dsm_handle
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ParallelContext * CreateParallelContext(const char *library_name, const char *function_name, int nworkers)
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Definition: miscinit.c:396
static void dlist_push_head(dlist_head *head, dlist_node *node)
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XLogRecPtr XactLastRecEnd
Definition: xlog.c:339
void shm_mq_detach(shm_mq_handle *mqh)
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PGPROC * MyProc
Definition: proc.c:67
static void pq_sendint32(StringInfo buf, int32 i)
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dsm_segment * seg
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static void WaitForParallelWorkersToExit(ParallelContext *pcxt)
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ResourceOwner CurrentResourceOwner
Definition: resowner.c:138
char * pstrdup(const char *in)
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shm_toc_estimator estimator
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char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
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#define SpinLockInit(lock)
Definition: spin.h:60
void GetTempNamespaceState(Oid *tempNamespaceId, Oid *tempToastNamespaceId)
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void RestoreTransactionSnapshot(Snapshot snapshot, void *master_pgproc)
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dsm_segment * dsm_attach(dsm_handle h)
Definition: dsm.c:548
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Oid authenticated_user_id
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static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
Snapshot GetActiveSnapshot(void)
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dsm_handle dsm_segment_handle(dsm_segment *seg)
Definition: dsm.c:1015
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int errcode(int sqlerrcode)
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PGPROC * parallel_master_pgproc
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Oid temp_toast_namespace_id
Definition: parallel.c:80
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void DetachSession(void)
Definition: session.c:201
BackgroundWorker * MyBgworkerEntry
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int snprintf(char *str, size_t count, const char *fmt,...) pg_attribute_printf(3
void MemoryContextReset(MemoryContext context)
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bool BecomeLockGroupMember(PGPROC *leader, int pid)
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Definition: snapmgr.c:812
uint32 SubTransactionId
Definition: c.h:449
Size shm_toc_estimate(shm_toc_estimator *e)
Definition: shm_toc.c:263
#define lengthof(array)
Definition: c.h:600
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Definition: latch.c:497
void SerializeTransactionState(Size maxsize, char *start_address)
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parallel_worker_main_type fn_addr
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const char * pq_getmsgrawstring(StringInfo msg)
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unsigned int Oid
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#define shm_toc_estimate_chunk(e, sz)
Definition: shm_toc.h:51
#define BGWORKER_SHMEM_ACCESS
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Snapshot GetTransactionSnapshot(void)
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void InvalidateSystemCaches(void)
Definition: inval.c:641
char bgw_function_name[BGW_MAXLEN]
Definition: bgworker.h:96
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Definition: pqformat.c:87
void RestoreComboCIDState(char *comboCIDstate)
Definition: combocid.c:344
signed int int32
Definition: c.h:284
SubTransactionId subid
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volatile bool ParallelMessagePending
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#define StaticAssertStmt(condition, errmessage)
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Definition: parallel.c:539
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Definition: spin.h:62
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ParallelWorkerInfo * worker
Definition: parallel.h:45
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Definition: latch.c:336
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Definition: xact.c:906
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Definition: dfmgr.c:728
#define ERROR
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Oid GetAuthenticatedUserId(void)
Definition: miscinit.c:343
#define PARALLEL_KEY_TRANSACTION_SNAPSHOT
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#define FATAL
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Definition: memutils.h:170
#define PARALLEL_KEY_FIXED
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#define PARALLEL_KEY_ERROR_QUEUE
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Size EstimateGUCStateSpace(void)
Definition: guc.c:9127
void AttachSession(dsm_handle handle)
Definition: session.c:155
#define BGW_NEVER_RESTART
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Definition: shm_toc.h:49
Size EstimateComboCIDStateSpace(void)
Definition: combocid.c:299
#define UInt32GetDatum(X)
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MemoryContext CurrentMemoryContext
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#define DLIST_STATIC_INIT(name)
Definition: ilist.h:248
#define WARNING
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int elevel
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bool ParallelContextActive(void)
Definition: parallel.c:703
#define SpinLockRelease(lock)
Definition: spin.h:64
#define dlist_head_element(type, membername, lhead)
Definition: ilist.h:487
Size EstimateSnapshotSpace(Snapshot snap)
Definition: snapmgr.c:2044
Size mul_size(Size s1, Size s2)
Definition: shmem.c:492
MemoryContext AllocSetContextCreate(MemoryContext parent, const char *name, Size minContextSize, Size initBlockSize, Size maxBlockSize)
Definition: aset.c:342
void * palloc0(Size size)
Definition: mcxt.c:877
static parallel_worker_main_type LookupParallelWorkerFunction(const char *libraryname, const char *funcname)
Definition: parallel.c:1203
void RestoreLibraryState(char *start_address)
Definition: dfmgr.c:750
uintptr_t Datum
Definition: postgres.h:372
dsm_segment * dsm_create(Size size, int flags)
Definition: dsm.c:452
shm_toc * shm_toc_attach(uint64 magic, void *address)
Definition: shm_toc.c:64
int GetDatabaseEncoding(void)
Definition: mbutils.c:1004
int BackendId
Definition: backendid.h:21
Oid MyDatabaseId
Definition: globals.c:77
pid_t parallel_master_pid
Definition: parallel.c:84
Size EstimateLibraryStateSpace(void)
Definition: dfmgr.c:711
void ReinitializeParallelDSM(ParallelContext *pcxt)
Definition: parallel.c:413
void shm_mq_set_handle(shm_mq_handle *mqh, BackgroundWorkerHandle *handle)
Definition: shm_mq.c:315
dlist_node * cur
Definition: ilist.h:161
#define PARALLEL_MAGIC
Definition: parallel.c:53
void pq_redirect_to_shm_mq(dsm_segment *seg, shm_mq_handle *mqh)
Definition: pqmq.c:55
void ParallelWorkerReportLastRecEnd(XLogRecPtr last_xlog_end)
Definition: parallel.c:1173
void TerminateBackgroundWorker(BackgroundWorkerHandle *handle)
Definition: bgworker.c:1184
pqsigfunc pqsignal(int signum, pqsigfunc handler)
Definition: signal.c:168
volatile bool InterruptPending
Definition: globals.c:29
int pq_getmsgbyte(StringInfo msg)
Definition: pqformat.c:401
shm_mq_result
Definition: shm_mq.h:36
char * library_name
Definition: parallel.h:38
void SetLatch(volatile Latch *latch)
Definition: latch.c:414
BackendId parallel_master_backend_id
Definition: parallel.c:85
int force_parallel_mode
Definition: planner.c:63
void * dsm_segment_address(dsm_segment *seg)
Definition: dsm.c:987
uint64 XLogRecPtr
Definition: xlogdefs.h:21
char bgw_name[BGW_MAXLEN]
Definition: bgworker.h:90
#define Assert(condition)
Definition: c.h:670
BackendId ParallelMasterBackendId
Definition: globals.c:75
void StartParallelWorkerTransaction(char *tstatespace)
Definition: xact.c:5061
#define BGWORKER_BACKEND_DATABASE_CONNECTION
Definition: bgworker.h:59
SubTransactionId GetCurrentSubTransactionId(void)
Definition: xact.c:642
Size EstimateTransactionStateSpace(void)
Definition: xact.c:4960
void StartTransactionCommand(void)
Definition: xact.c:2673
const char * fn_name
Definition: parallel.c:120
static bool dlist_is_empty(dlist_head *head)
Definition: ilist.h:289
#define DSM_IMPL_NONE
Definition: dsm_impl.h:17
#define BGW_MAXLEN
Definition: bgworker.h:85
size_t Size
Definition: c.h:404
BgWorkerStartTime bgw_start_time
Definition: bgworker.h:93
dlist_node node
Definition: parallel.h:34
#define shm_toc_estimate_keys(e, cnt)
Definition: shm_toc.h:53
bool RegisterDynamicBackgroundWorker(BackgroundWorker *worker, BackgroundWorkerHandle **handle)
Definition: bgworker.c:939
void EnterParallelMode(void)
Definition: xact.c:873
void * shm_toc_allocate(shm_toc *toc, Size nbytes)
Definition: shm_toc.c:88
char * context
Definition: elog.h:347
shm_mq_handle * shm_mq_attach(shm_mq *mq, dsm_segment *seg, BackgroundWorkerHandle *handle)
Definition: shm_mq.c:287
ErrorContextCallback * error_context_stack
Definition: parallel.h:40
void pq_set_parallel_master(pid_t pid, BackendId backend_id)
Definition: pqmq.c:80
#define PARALLEL_KEY_TRANSACTION_STATE
Definition: parallel.c:67
char bgw_type[BGW_MAXLEN]
Definition: bgworker.h:91
void dsm_detach(dsm_segment *seg)
Definition: dsm.c:713
void shm_toc_insert(shm_toc *toc, uint64 key, void *address)
Definition: shm_toc.c:171
int errmsg(const char *fmt,...)
Definition: elog.c:797
void(* parallel_worker_main_type)(dsm_segment *seg, shm_toc *toc)
Definition: parallel.h:23
#define IsolationIsSerializable()
Definition: xact.h:44
void pq_endmessage(StringInfo buf)
Definition: pqformat.c:298
void ParallelWorkerMain(Datum main_arg)
Definition: parallel.c:957
pid_t bgw_notify_pid
Definition: bgworker.h:99
static FixedParallelState * MyFixedParallelState
Definition: parallel.c:109
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:706
void die(SIGNAL_ARGS)
Definition: postgres.c:2652
void SetCurrentRoleId(Oid roleid, bool is_superuser)
Definition: miscinit.c:657
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:115
bool InitializingParallelWorker
Definition: parallel.c:106
int i
Definition: shm_mq.c:69
#define PARALLEL_KEY_SESSION_DSM
Definition: parallel.c:69
#define BUFFERALIGN(LEN)
Definition: c.h:625
struct Latch * MyLatch
Definition: globals.c:52
void HandleParallelMessageInterrupt(void)
Definition: parallel.c:716
unsigned int pq_getmsgint(StringInfo msg, int b)
Definition: pqformat.c:417
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:98
void shm_mq_set_receiver(shm_mq *mq, PGPROC *proc)
Definition: shm_mq.c:199
static dlist_head pcxt_list
Definition: parallel.c:112
#define elog
Definition: elog.h:219
void pq_getmsgend(StringInfo msg)
Definition: pqformat.c:637
#define pq_putmessage(msgtype, s, len)
Definition: libpq.h:42
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:225
struct FixedParallelState FixedParallelState
dsm_handle GetSessionDsmHandle(void)
Definition: session.c:70
shm_mq_result shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait)
Definition: shm_mq.c:522
char bgw_library_name[BGW_MAXLEN]
Definition: bgworker.h:95
bool session_auth_is_superuser
Definition: guc.c:449
void AtEOXact_Parallel(bool isCommit)
Definition: parallel.c:940
Definition: proc.h:95
#define PARALLEL_KEY_ENTRYPOINT
Definition: parallel.c:68
#define PARALLEL_KEY_COMBO_CID
Definition: parallel.c:64
#define WL_LATCH_SET
Definition: latch.h:124
#define _(x)
Definition: elog.c:84
void AtEOSubXact_Parallel(bool isCommit, SubTransactionId mySubId)
Definition: parallel.c:921
void SerializeGUCState(Size maxsize, char *start_address)
Definition: guc.c:9274
void appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
Definition: stringinfo.c:208
#define PARALLEL_KEY_ACTIVE_SNAPSHOT
Definition: parallel.c:66
void * shm_toc_lookup(shm_toc *toc, uint64 key, bool noError)
Definition: shm_toc.c:232
void SerializeComboCIDState(Size maxsize, char *start_address)
Definition: combocid.c:318
#define PARALLEL_KEY_LIBRARY
Definition: parallel.c:62
void RestoreGUCState(void *gucstate)
Definition: guc.c:9339
shm_toc * toc
Definition: parallel.h:44
void NotifyMyFrontEnd(const char *channel, const char *payload, int32 srcPid)
Definition: async.c:2096
void * private_memory
Definition: parallel.h:43
ResourceOwner ResourceOwnerCreate(ResourceOwner parent, const char *name)
Definition: resowner.c:416
void BackgroundWorkerUnblockSignals(void)
Definition: postmaster.c:5640