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syncrep.c File Reference
#include "postgres.h"
#include <unistd.h>
#include "access/xact.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "replication/syncrep.h"
#include "replication/walsender.h"
#include "replication/walsender_private.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/ps_status.h"
Include dependency graph for syncrep.c:

Go to the source code of this file.

Macros

#define SyncStandbysDefined()   (SyncRepStandbyNames != NULL && SyncRepStandbyNames[0] != '\0')
 

Functions

static void SyncRepQueueInsert (int mode)
 
static void SyncRepCancelWait (void)
 
static int SyncRepWakeQueue (bool all, int mode)
 
static bool SyncRepGetSyncRecPtr (XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, bool *am_sync)
 
static void SyncRepGetOldestSyncRecPtr (XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, List *sync_standbys)
 
static void SyncRepGetNthLatestSyncRecPtr (XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, List *sync_standbys, uint8 nth)
 
static int SyncRepGetStandbyPriority (void)
 
static ListSyncRepGetSyncStandbysPriority (bool *am_sync)
 
static ListSyncRepGetSyncStandbysQuorum (bool *am_sync)
 
static int cmp_lsn (const void *a, const void *b)
 
void SyncRepWaitForLSN (XLogRecPtr lsn, bool commit)
 
void SyncRepCleanupAtProcExit (void)
 
void SyncRepInitConfig (void)
 
void SyncRepReleaseWaiters (void)
 
ListSyncRepGetSyncStandbys (bool *am_sync)
 
void SyncRepUpdateSyncStandbysDefined (void)
 
bool check_synchronous_standby_names (char **newval, void **extra, GucSource source)
 
void assign_synchronous_standby_names (const char *newval, void *extra)
 
void assign_synchronous_commit (int newval, void *extra)
 

Variables

char * SyncRepStandbyNames
 
static bool announce_next_takeover = true
 
SyncRepConfigDataSyncRepConfig = NULL
 
static int SyncRepWaitMode = SYNC_REP_NO_WAIT
 

Macro Definition Documentation

#define SyncStandbysDefined ( )    (SyncRepStandbyNames != NULL && SyncRepStandbyNames[0] != '\0')

Function Documentation

void assign_synchronous_commit ( int  newval,
void *  extra 
)

Definition at line 1173 of file syncrep.c.

References SYNC_REP_NO_WAIT, SYNC_REP_WAIT_APPLY, SYNC_REP_WAIT_FLUSH, SYNC_REP_WAIT_WRITE, SYNCHRONOUS_COMMIT_REMOTE_APPLY, SYNCHRONOUS_COMMIT_REMOTE_FLUSH, SYNCHRONOUS_COMMIT_REMOTE_WRITE, and SyncRepWaitMode.

1174 {
1175  switch (newval)
1176  {
1179  break;
1182  break;
1185  break;
1186  default:
1188  break;
1189  }
1190 }
#define SYNC_REP_NO_WAIT
Definition: syncrep.h:23
#define SYNC_REP_WAIT_APPLY
Definition: syncrep.h:26
#define SYNC_REP_WAIT_FLUSH
Definition: syncrep.h:25
#define newval
static int SyncRepWaitMode
Definition: syncrep.c:98
#define SYNC_REP_WAIT_WRITE
Definition: syncrep.h:24
void assign_synchronous_standby_names ( const char *  newval,
void *  extra 
)

Definition at line 1167 of file syncrep.c.

1168 {
1169  SyncRepConfig = (SyncRepConfigData *) extra;
1170 }
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
bool check_synchronous_standby_names ( char **  newval,
void **  extra,
GucSource  source 
)

Definition at line 1110 of file syncrep.c.

References SyncRepConfigData::config_size, GUC_check_errcode(), GUC_check_errdetail, GUC_check_errmsg, malloc, NULL, SyncRepConfigData::num_sync, syncrep_parse_error_msg, syncrep_parse_result, syncrep_scanner_finish(), syncrep_scanner_init(), and syncrep_yyparse().

1111 {
1112  if (*newval != NULL && (*newval)[0] != '\0')
1113  {
1114  int parse_rc;
1115  SyncRepConfigData *pconf;
1116 
1117  /* Reset communication variables to ensure a fresh start */
1120 
1121  /* Parse the synchronous_standby_names string */
1123  parse_rc = syncrep_yyparse();
1125 
1126  if (parse_rc != 0 || syncrep_parse_result == NULL)
1127  {
1128  GUC_check_errcode(ERRCODE_SYNTAX_ERROR);
1131  else
1132  GUC_check_errdetail("synchronous_standby_names parser failed");
1133  return false;
1134  }
1135 
1136  if (syncrep_parse_result->num_sync <= 0)
1137  {
1138  GUC_check_errmsg("number of synchronous standbys (%d) must be greater than zero",
1140  return false;
1141  }
1142 
1143  /* GUC extra value must be malloc'd, not palloc'd */
1144  pconf = (SyncRepConfigData *)
1146  if (pconf == NULL)
1147  return false;
1149 
1150  *extra = (void *) pconf;
1151 
1152  /*
1153  * We need not explicitly clean up syncrep_parse_result. It, and any
1154  * other cruft generated during parsing, will be freed when the
1155  * current memory context is deleted. (This code is generally run in
1156  * a short-lived context used for config file processing, so that will
1157  * not be very long.)
1158  */
1159  }
1160  else
1161  *extra = NULL;
1162 
1163  return true;
1164 }
void syncrep_scanner_finish(void)
void syncrep_scanner_init(const char *query_string)
#define GUC_check_errdetail
Definition: guc.h:407
char * syncrep_parse_error_msg
#define GUC_check_errmsg
Definition: guc.h:403
void GUC_check_errcode(int sqlerrcode)
Definition: guc.c:9773
#define malloc(a)
Definition: header.h:50
#define NULL
Definition: c.h:229
SyncRepConfigData * syncrep_parse_result
#define newval
int syncrep_yyparse(void)
static int cmp_lsn ( const void *  a,
const void *  b 
)
static

Definition at line 655 of file syncrep.c.

Referenced by SyncRepGetNthLatestSyncRecPtr().

656 {
657  XLogRecPtr lsn1 = *((const XLogRecPtr *) a);
658  XLogRecPtr lsn2 = *((const XLogRecPtr *) b);
659 
660  if (lsn1 > lsn2)
661  return -1;
662  else if (lsn1 == lsn2)
663  return 0;
664  else
665  return 1;
666 }
uint64 XLogRecPtr
Definition: xlogdefs.h:21
static void SyncRepCancelWait ( void  )
static

Definition at line 350 of file syncrep.c.

References LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, SHMQueueDelete(), SHMQueueIsDetached(), SYNC_REP_NOT_WAITING, PGPROC::syncRepLinks, and PGPROC::syncRepState.

Referenced by SyncRepWaitForLSN().

351 {
352  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
356  LWLockRelease(SyncRepLock);
357 }
PGPROC * MyProc
Definition: proc.c:67
#define SYNC_REP_NOT_WAITING
Definition: syncrep.h:31
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
bool SHMQueueIsDetached(const SHM_QUEUE *queue)
Definition: shmqueue.c:47
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
SHM_QUEUE syncRepLinks
Definition: proc.h:149
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68
int syncRepState
Definition: proc.h:148
void SyncRepCleanupAtProcExit ( void  )

Definition at line 360 of file syncrep.c.

References LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, SHMQueueDelete(), SHMQueueIsDetached(), and PGPROC::syncRepLinks.

Referenced by ProcKill().

361 {
363  {
364  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
366  LWLockRelease(SyncRepLock);
367  }
368 }
PGPROC * MyProc
Definition: proc.c:67
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
bool SHMQueueIsDetached(const SHM_QUEUE *queue)
Definition: shmqueue.c:47
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
SHM_QUEUE syncRepLinks
Definition: proc.h:149
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68
static void SyncRepGetNthLatestSyncRecPtr ( XLogRecPtr writePtr,
XLogRecPtr flushPtr,
XLogRecPtr applyPtr,
List sync_standbys,
uint8  nth 
)
static

Definition at line 608 of file syncrep.c.

References WalSnd::apply, cmp_lsn(), WalSnd::flush, i, lfirst_int, list_length(), WalSnd::mutex, palloc(), pfree(), qsort, SpinLockAcquire, SpinLockRelease, WalSndCtl, WalSndCtlData::walsnds, and WalSnd::write.

Referenced by SyncRepGetSyncRecPtr().

610 {
611  ListCell *cell;
612  XLogRecPtr *write_array;
613  XLogRecPtr *flush_array;
614  XLogRecPtr *apply_array;
615  int len;
616  int i = 0;
617 
618  len = list_length(sync_standbys);
619  write_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
620  flush_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
621  apply_array = (XLogRecPtr *) palloc(sizeof(XLogRecPtr) * len);
622 
623  foreach(cell, sync_standbys)
624  {
625  WalSnd *walsnd = &WalSndCtl->walsnds[lfirst_int(cell)];
626 
627  SpinLockAcquire(&walsnd->mutex);
628  write_array[i] = walsnd->write;
629  flush_array[i] = walsnd->flush;
630  apply_array[i] = walsnd->apply;
631  SpinLockRelease(&walsnd->mutex);
632 
633  i++;
634  }
635 
636  /* Sort each array in descending order */
637  qsort(write_array, len, sizeof(XLogRecPtr), cmp_lsn);
638  qsort(flush_array, len, sizeof(XLogRecPtr), cmp_lsn);
639  qsort(apply_array, len, sizeof(XLogRecPtr), cmp_lsn);
640 
641  /* Get Nth latest Write, Flush, Apply positions */
642  *writePtr = write_array[nth - 1];
643  *flushPtr = flush_array[nth - 1];
644  *applyPtr = apply_array[nth - 1];
645 
646  pfree(write_array);
647  pfree(flush_array);
648  pfree(apply_array);
649 }
XLogRecPtr write
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
WalSnd walsnds[FLEXIBLE_ARRAY_MEMBER]
slock_t mutex
#define SpinLockAcquire(lock)
Definition: spin.h:62
XLogRecPtr flush
void pfree(void *pointer)
Definition: mcxt.c:950
static int cmp_lsn(const void *a, const void *b)
Definition: syncrep.c:655
#define lfirst_int(lc)
Definition: pg_list.h:107
#define SpinLockRelease(lock)
Definition: spin.h:64
uint64 XLogRecPtr
Definition: xlogdefs.h:21
static int list_length(const List *l)
Definition: pg_list.h:89
void * palloc(Size size)
Definition: mcxt.c:849
int i
#define qsort(a, b, c, d)
Definition: port.h:440
XLogRecPtr apply
static void SyncRepGetOldestSyncRecPtr ( XLogRecPtr writePtr,
XLogRecPtr flushPtr,
XLogRecPtr applyPtr,
List sync_standbys 
)
static

Definition at line 572 of file syncrep.c.

References WalSnd::apply, WalSnd::flush, lfirst_int, WalSnd::mutex, SpinLockAcquire, SpinLockRelease, WalSndCtl, WalSndCtlData::walsnds, write, WalSnd::write, and XLogRecPtrIsInvalid.

Referenced by SyncRepGetSyncRecPtr().

574 {
575  ListCell *cell;
576 
577  /*
578  * Scan through all sync standbys and calculate the oldest Write, Flush
579  * and Apply positions.
580  */
581  foreach(cell, sync_standbys)
582  {
583  WalSnd *walsnd = &WalSndCtl->walsnds[lfirst_int(cell)];
585  XLogRecPtr flush;
586  XLogRecPtr apply;
587 
588  SpinLockAcquire(&walsnd->mutex);
589  write = walsnd->write;
590  flush = walsnd->flush;
591  apply = walsnd->apply;
592  SpinLockRelease(&walsnd->mutex);
593 
594  if (XLogRecPtrIsInvalid(*writePtr) || *writePtr > write)
595  *writePtr = write;
596  if (XLogRecPtrIsInvalid(*flushPtr) || *flushPtr > flush)
597  *flushPtr = flush;
598  if (XLogRecPtrIsInvalid(*applyPtr) || *applyPtr > apply)
599  *applyPtr = apply;
600  }
601 }
XLogRecPtr write
#define write(a, b, c)
Definition: win32.h:14
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
WalSnd walsnds[FLEXIBLE_ARRAY_MEMBER]
slock_t mutex
#define SpinLockAcquire(lock)
Definition: spin.h:62
XLogRecPtr flush
#define lfirst_int(lc)
Definition: pg_list.h:107
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
#define SpinLockRelease(lock)
Definition: spin.h:64
uint64 XLogRecPtr
Definition: xlogdefs.h:21
XLogRecPtr apply
static int SyncRepGetStandbyPriority ( void  )
static

Definition at line 926 of file syncrep.c.

References am_cascading_walsender, application_name, SyncRepConfigData::member_names, SyncRepConfigData::nmembers, NULL, pg_strcasecmp(), SYNC_REP_PRIORITY, SyncRepConfigData::syncrep_method, and SyncStandbysDefined.

Referenced by SyncRepInitConfig().

927 {
928  const char *standby_name;
929  int priority;
930  bool found = false;
931 
932  /*
933  * Since synchronous cascade replication is not allowed, we always set the
934  * priority of cascading walsender to zero.
935  */
937  return 0;
938 
940  return 0;
941 
942  standby_name = SyncRepConfig->member_names;
943  for (priority = 1; priority <= SyncRepConfig->nmembers; priority++)
944  {
945  if (pg_strcasecmp(standby_name, application_name) == 0 ||
946  strcmp(standby_name, "*") == 0)
947  {
948  found = true;
949  break;
950  }
951  standby_name += strlen(standby_name) + 1;
952  }
953 
954  if (!found)
955  return 0;
956 
957  /*
958  * In quorum-based sync replication, all the standbys in the list have the
959  * same priority, one.
960  */
961  return (SyncRepConfig->syncrep_method == SYNC_REP_PRIORITY) ? priority : 1;
962 }
#define SYNC_REP_PRIORITY
Definition: syncrep.h:36
uint8 syncrep_method
Definition: syncrep.h:51
int pg_strcasecmp(const char *s1, const char *s2)
Definition: pgstrcasecmp.c:36
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
#define SyncStandbysDefined()
Definition: syncrep.c:92
#define NULL
Definition: c.h:229
char member_names[FLEXIBLE_ARRAY_MEMBER]
Definition: syncrep.h:54
char * application_name
Definition: guc.c:469
bool am_cascading_walsender
Definition: walsender.c:112
static bool SyncRepGetSyncRecPtr ( XLogRecPtr writePtr,
XLogRecPtr flushPtr,
XLogRecPtr applyPtr,
bool am_sync 
)
static

Definition at line 515 of file syncrep.c.

References InvalidXLogRecPtr, list_free(), list_length(), NULL, SyncRepConfigData::num_sync, SYNC_REP_PRIORITY, SyncRepConfigData::syncrep_method, SyncRepGetNthLatestSyncRecPtr(), SyncRepGetOldestSyncRecPtr(), and SyncRepGetSyncStandbys().

Referenced by SyncRepReleaseWaiters().

517 {
518  List *sync_standbys;
519 
520  *writePtr = InvalidXLogRecPtr;
521  *flushPtr = InvalidXLogRecPtr;
522  *applyPtr = InvalidXLogRecPtr;
523  *am_sync = false;
524 
525  /* Get standbys that are considered as synchronous at this moment */
526  sync_standbys = SyncRepGetSyncStandbys(am_sync);
527 
528  /*
529  * Quick exit if we are not managing a sync standby or there are not
530  * enough synchronous standbys.
531  */
532  if (!(*am_sync) ||
533  SyncRepConfig == NULL ||
534  list_length(sync_standbys) < SyncRepConfig->num_sync)
535  {
536  list_free(sync_standbys);
537  return false;
538  }
539 
540  /*
541  * In a priority-based sync replication, the synced positions are the
542  * oldest ones among sync standbys. In a quorum-based, they are the Nth
543  * latest ones.
544  *
545  * SyncRepGetNthLatestSyncRecPtr() also can calculate the oldest
546  * positions. But we use SyncRepGetOldestSyncRecPtr() for that calculation
547  * because it's a bit more efficient.
548  *
549  * XXX If the numbers of current and requested sync standbys are the same,
550  * we can use SyncRepGetOldestSyncRecPtr() to calculate the synced
551  * positions even in a quorum-based sync replication.
552  */
554  {
555  SyncRepGetOldestSyncRecPtr(writePtr, flushPtr, applyPtr,
556  sync_standbys);
557  }
558  else
559  {
560  SyncRepGetNthLatestSyncRecPtr(writePtr, flushPtr, applyPtr,
561  sync_standbys, SyncRepConfig->num_sync);
562  }
563 
564  list_free(sync_standbys);
565  return true;
566 }
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define SYNC_REP_PRIORITY
Definition: syncrep.h:36
uint8 syncrep_method
Definition: syncrep.h:51
static void SyncRepGetNthLatestSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, List *sync_standbys, uint8 nth)
Definition: syncrep.c:608
List * SyncRepGetSyncStandbys(bool *am_sync)
Definition: syncrep.c:677
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
#define NULL
Definition: c.h:229
static int list_length(const List *l)
Definition: pg_list.h:89
void list_free(List *list)
Definition: list.c:1133
static void SyncRepGetOldestSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, List *sync_standbys)
Definition: syncrep.c:572
Definition: pg_list.h:45
List* SyncRepGetSyncStandbys ( bool am_sync)

Definition at line 677 of file syncrep.c.

References NIL, NULL, SYNC_REP_PRIORITY, SyncRepConfigData::syncrep_method, SyncRepGetSyncStandbysPriority(), and SyncRepGetSyncStandbysQuorum().

Referenced by pg_stat_get_wal_senders(), and SyncRepGetSyncRecPtr().

678 {
679  /* Set default result */
680  if (am_sync != NULL)
681  *am_sync = false;
682 
683  /* Quick exit if sync replication is not requested */
684  if (SyncRepConfig == NULL)
685  return NIL;
686 
690 }
#define NIL
Definition: pg_list.h:69
static List * SyncRepGetSyncStandbysPriority(bool *am_sync)
Definition: syncrep.c:758
#define SYNC_REP_PRIORITY
Definition: syncrep.h:36
uint8 syncrep_method
Definition: syncrep.h:51
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
static List * SyncRepGetSyncStandbysQuorum(bool *am_sync)
Definition: syncrep.c:703
#define NULL
Definition: c.h:229
static List * SyncRepGetSyncStandbysPriority ( bool am_sync)
static

Definition at line 758 of file syncrep.c.

References Assert, WalSnd::flush, i, lappend_int(), lfirst_int, list_concat(), list_delete_cell(), list_free(), list_head(), list_length(), lnext, max_wal_senders, MyWalSnd, next, NIL, SyncRepConfigData::nmembers, NULL, SyncRepConfigData::num_sync, pfree(), WalSnd::pid, result, WalSnd::state, SYNC_REP_PRIORITY, WalSnd::sync_standby_priority, SyncRepConfigData::syncrep_method, WalSndCtl, WalSndCtlData::walsnds, WALSNDSTATE_STREAMING, and XLogRecPtrIsInvalid.

Referenced by SyncRepGetSyncStandbys().

759 {
760  List *result = NIL;
761  List *pending = NIL;
762  int lowest_priority;
763  int next_highest_priority;
764  int this_priority;
765  int priority;
766  int i;
767  bool am_in_pending = false;
768  volatile WalSnd *walsnd; /* Use volatile pointer to prevent code
769  * rearrangement */
770 
772 
773  lowest_priority = SyncRepConfig->nmembers;
774  next_highest_priority = lowest_priority + 1;
775 
776  /*
777  * Find the sync standbys which have the highest priority (i.e, 1). Also
778  * store all the other potential sync standbys into the pending list, in
779  * order to scan it later and find other sync standbys from it quickly.
780  */
781  for (i = 0; i < max_wal_senders; i++)
782  {
783  walsnd = &WalSndCtl->walsnds[i];
784 
785  /* Must be active */
786  if (walsnd->pid == 0)
787  continue;
788 
789  /* Must be streaming */
790  if (walsnd->state != WALSNDSTATE_STREAMING)
791  continue;
792 
793  /* Must be synchronous */
794  this_priority = walsnd->sync_standby_priority;
795  if (this_priority == 0)
796  continue;
797 
798  /* Must have a valid flush position */
799  if (XLogRecPtrIsInvalid(walsnd->flush))
800  continue;
801 
802  /*
803  * If the priority is equal to 1, consider this standby as sync and
804  * append it to the result. Otherwise append this standby to the
805  * pending list to check if it's actually sync or not later.
806  */
807  if (this_priority == 1)
808  {
809  result = lappend_int(result, i);
810  if (am_sync != NULL && walsnd == MyWalSnd)
811  *am_sync = true;
812  if (list_length(result) == SyncRepConfig->num_sync)
813  {
814  list_free(pending);
815  return result; /* Exit if got enough sync standbys */
816  }
817  }
818  else
819  {
820  pending = lappend_int(pending, i);
821  if (am_sync != NULL && walsnd == MyWalSnd)
822  am_in_pending = true;
823 
824  /*
825  * Track the highest priority among the standbys in the pending
826  * list, in order to use it as the starting priority for later
827  * scan of the list. This is useful to find quickly the sync
828  * standbys from the pending list later because we can skip
829  * unnecessary scans for the unused priorities.
830  */
831  if (this_priority < next_highest_priority)
832  next_highest_priority = this_priority;
833  }
834  }
835 
836  /*
837  * Consider all pending standbys as sync if the number of them plus
838  * already-found sync ones is lower than the configuration requests.
839  */
840  if (list_length(result) + list_length(pending) <= SyncRepConfig->num_sync)
841  {
842  bool needfree = (result != NIL && pending != NIL);
843 
844  /*
845  * Set *am_sync to true if this walsender is in the pending list
846  * because all pending standbys are considered as sync.
847  */
848  if (am_sync != NULL && !(*am_sync))
849  *am_sync = am_in_pending;
850 
851  result = list_concat(result, pending);
852  if (needfree)
853  pfree(pending);
854  return result;
855  }
856 
857  /*
858  * Find the sync standbys from the pending list.
859  */
860  priority = next_highest_priority;
861  while (priority <= lowest_priority)
862  {
863  ListCell *cell;
864  ListCell *prev = NULL;
865  ListCell *next;
866 
867  next_highest_priority = lowest_priority + 1;
868 
869  for (cell = list_head(pending); cell != NULL; cell = next)
870  {
871  i = lfirst_int(cell);
872  walsnd = &WalSndCtl->walsnds[i];
873 
874  next = lnext(cell);
875 
876  this_priority = walsnd->sync_standby_priority;
877  if (this_priority == priority)
878  {
879  result = lappend_int(result, i);
880  if (am_sync != NULL && walsnd == MyWalSnd)
881  *am_sync = true;
882 
883  /*
884  * We should always exit here after the scan of pending list
885  * starts because we know that the list has enough elements to
886  * reach SyncRepConfig->num_sync.
887  */
888  if (list_length(result) == SyncRepConfig->num_sync)
889  {
890  list_free(pending);
891  return result; /* Exit if got enough sync standbys */
892  }
893 
894  /*
895  * Remove the entry for this sync standby from the list to
896  * prevent us from looking at the same entry again.
897  */
898  pending = list_delete_cell(pending, cell, prev);
899 
900  continue;
901  }
902 
903  if (this_priority < next_highest_priority)
904  next_highest_priority = this_priority;
905 
906  prev = cell;
907  }
908 
909  priority = next_highest_priority;
910  }
911 
912  /* never reached, but keep compiler quiet */
913  Assert(false);
914  return result;
915 }
#define NIL
Definition: pg_list.h:69
static int32 next
Definition: blutils.c:210
#define SYNC_REP_PRIORITY
Definition: syncrep.h:36
uint8 syncrep_method
Definition: syncrep.h:51
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
List * list_concat(List *list1, List *list2)
Definition: list.c:321
return result
Definition: formatting.c:1632
WalSnd walsnds[FLEXIBLE_ARRAY_MEMBER]
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
XLogRecPtr flush
void pfree(void *pointer)
Definition: mcxt.c:950
#define lfirst_int(lc)
Definition: pg_list.h:107
WalSndState state
static ListCell * list_head(const List *l)
Definition: pg_list.h:77
#define lnext(lc)
Definition: pg_list.h:105
List * lappend_int(List *list, int datum)
Definition: list.c:146
int max_wal_senders
Definition: walsender.c:117
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
List * list_delete_cell(List *list, ListCell *cell, ListCell *prev)
Definition: list.c:528
WalSnd * MyWalSnd
Definition: walsender.c:108
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
int sync_standby_priority
static int list_length(const List *l)
Definition: pg_list.h:89
void list_free(List *list)
Definition: list.c:1133
int i
Definition: pg_list.h:45
static List * SyncRepGetSyncStandbysQuorum ( bool am_sync)
static

Definition at line 703 of file syncrep.c.

References Assert, WalSnd::flush, i, lappend_int(), max_wal_senders, MyWalSnd, NIL, NULL, WalSnd::pid, result, WalSnd::state, SYNC_REP_QUORUM, WalSnd::sync_standby_priority, SyncRepConfigData::syncrep_method, WalSndCtl, WalSndCtlData::walsnds, WALSNDSTATE_STREAMING, and XLogRecPtrIsInvalid.

Referenced by SyncRepGetSyncStandbys().

704 {
705  List *result = NIL;
706  int i;
707  volatile WalSnd *walsnd; /* Use volatile pointer to prevent code
708  * rearrangement */
709 
711 
712  for (i = 0; i < max_wal_senders; i++)
713  {
714  walsnd = &WalSndCtl->walsnds[i];
715 
716  /* Must be active */
717  if (walsnd->pid == 0)
718  continue;
719 
720  /* Must be streaming */
721  if (walsnd->state != WALSNDSTATE_STREAMING)
722  continue;
723 
724  /* Must be synchronous */
725  if (walsnd->sync_standby_priority == 0)
726  continue;
727 
728  /* Must have a valid flush position */
729  if (XLogRecPtrIsInvalid(walsnd->flush))
730  continue;
731 
732  /*
733  * Consider this standby as a candidate for quorum sync standbys and
734  * append it to the result.
735  */
736  result = lappend_int(result, i);
737  if (am_sync != NULL && walsnd == MyWalSnd)
738  *am_sync = true;
739  }
740 
741  return result;
742 }
#define NIL
Definition: pg_list.h:69
uint8 syncrep_method
Definition: syncrep.h:51
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
return result
Definition: formatting.c:1632
WalSnd walsnds[FLEXIBLE_ARRAY_MEMBER]
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
XLogRecPtr flush
WalSndState state
List * lappend_int(List *list, int datum)
Definition: list.c:146
int max_wal_senders
Definition: walsender.c:117
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
WalSnd * MyWalSnd
Definition: walsender.c:108
#define SYNC_REP_QUORUM
Definition: syncrep.h:37
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
int sync_standby_priority
int i
Definition: pg_list.h:45
void SyncRepInitConfig ( void  )

Definition at line 381 of file syncrep.c.

References application_name, DEBUG1, ereport, errmsg(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyWalSnd, WalSnd::sync_standby_priority, and SyncRepGetStandbyPriority().

Referenced by StartLogicalReplication(), StartReplication(), WalSndLoop(), WalSndWaitForWal(), and WalSndWriteData().

382 {
383  int priority;
384 
385  /*
386  * Determine if we are a potential sync standby and remember the result
387  * for handling replies from standby.
388  */
389  priority = SyncRepGetStandbyPriority();
390  if (MyWalSnd->sync_standby_priority != priority)
391  {
392  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
393  MyWalSnd->sync_standby_priority = priority;
394  LWLockRelease(SyncRepLock);
395  ereport(DEBUG1,
396  (errmsg("standby \"%s\" now has synchronous standby priority %u",
397  application_name, priority)));
398  }
399 }
#define DEBUG1
Definition: elog.h:25
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
#define ereport(elevel, rest)
Definition: elog.h:122
WalSnd * MyWalSnd
Definition: walsender.c:108
int sync_standby_priority
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
char * application_name
Definition: guc.c:469
int errmsg(const char *fmt,...)
Definition: elog.c:797
static int SyncRepGetStandbyPriority(void)
Definition: syncrep.c:926
static void SyncRepQueueInsert ( int  mode)
static

Definition at line 317 of file syncrep.c.

References Assert, MyProc, NUM_SYNC_REP_WAIT_MODE, offsetof, SHMQueueInsertAfter(), SHMQueuePrev(), PGPROC::syncRepLinks, WalSndCtlData::SyncRepQueue, PGPROC::waitLSN, and WalSndCtl.

Referenced by SyncRepWaitForLSN().

318 {
319  PGPROC *proc;
320 
321  Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
322  proc = (PGPROC *) SHMQueuePrev(&(WalSndCtl->SyncRepQueue[mode]),
323  &(WalSndCtl->SyncRepQueue[mode]),
324  offsetof(PGPROC, syncRepLinks));
325 
326  while (proc)
327  {
328  /*
329  * Stop at the queue element that we should after to ensure the queue
330  * is ordered by LSN.
331  */
332  if (proc->waitLSN < MyProc->waitLSN)
333  break;
334 
335  proc = (PGPROC *) SHMQueuePrev(&(WalSndCtl->SyncRepQueue[mode]),
336  &(proc->syncRepLinks),
337  offsetof(PGPROC, syncRepLinks));
338  }
339 
340  if (proc)
342  else
344 }
Pointer SHMQueuePrev(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:164
PGPROC * MyProc
Definition: proc.c:67
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
void SHMQueueInsertAfter(SHM_QUEUE *queue, SHM_QUEUE *elem)
Definition: shmqueue.c:108
SHM_QUEUE SyncRepQueue[NUM_SYNC_REP_WAIT_MODE]
#define Assert(condition)
Definition: c.h:675
SHM_QUEUE syncRepLinks
Definition: proc.h:149
#define NUM_SYNC_REP_WAIT_MODE
Definition: syncrep.h:28
Definition: proc.h:94
XLogRecPtr waitLSN
Definition: proc.h:147
#define offsetof(type, field)
Definition: c.h:555
void SyncRepReleaseWaiters ( void  )

Definition at line 409 of file syncrep.c.

References announce_next_takeover, application_name, DEBUG3, elog, ereport, errmsg(), WalSnd::flush, LOG, WalSndCtlData::lsn, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyWalSnd, WalSnd::state, SYNC_REP_PRIORITY, SYNC_REP_WAIT_APPLY, SYNC_REP_WAIT_FLUSH, SYNC_REP_WAIT_WRITE, WalSnd::sync_standby_priority, SyncRepConfigData::syncrep_method, SyncRepGetSyncRecPtr(), SyncRepWakeQueue(), WalSndCtl, WALSNDSTATE_STREAMING, and XLogRecPtrIsInvalid.

Referenced by ProcessStandbyReplyMessage().

410 {
411  volatile WalSndCtlData *walsndctl = WalSndCtl;
412  XLogRecPtr writePtr;
413  XLogRecPtr flushPtr;
414  XLogRecPtr applyPtr;
415  bool got_recptr;
416  bool am_sync;
417  int numwrite = 0;
418  int numflush = 0;
419  int numapply = 0;
420 
421  /*
422  * If this WALSender is serving a standby that is not on the list of
423  * potential sync standbys then we have nothing to do. If we are still
424  * starting up, still running base backup or the current flush position is
425  * still invalid, then leave quickly also.
426  */
427  if (MyWalSnd->sync_standby_priority == 0 ||
430  {
431  announce_next_takeover = true;
432  return;
433  }
434 
435  /*
436  * We're a potential sync standby. Release waiters if there are enough
437  * sync standbys and we are considered as sync.
438  */
439  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
440 
441  /*
442  * Check whether we are a sync standby or not, and calculate the synced
443  * positions among all sync standbys.
444  */
445  got_recptr = SyncRepGetSyncRecPtr(&writePtr, &flushPtr, &applyPtr, &am_sync);
446 
447  /*
448  * If we are managing a sync standby, though we weren't prior to this,
449  * then announce we are now a sync standby.
450  */
451  if (announce_next_takeover && am_sync)
452  {
453  announce_next_takeover = false;
454 
456  ereport(LOG,
457  (errmsg("standby \"%s\" is now a synchronous standby with priority %u",
459  else
460  ereport(LOG,
461  (errmsg("standby \"%s\" is now a candidate for quorum synchronous standby",
462  application_name)));
463  }
464 
465  /*
466  * If the number of sync standbys is less than requested or we aren't
467  * managing a sync standby then just leave.
468  */
469  if (!got_recptr || !am_sync)
470  {
471  LWLockRelease(SyncRepLock);
472  announce_next_takeover = !am_sync;
473  return;
474  }
475 
476  /*
477  * Set the lsn first so that when we wake backends they will release up to
478  * this location.
479  */
480  if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
481  {
482  walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
483  numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
484  }
485  if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
486  {
487  walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
488  numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
489  }
490  if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
491  {
492  walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
493  numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
494  }
495 
496  LWLockRelease(SyncRepLock);
497 
498  elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X, %d procs up to apply %X/%X",
499  numwrite, (uint32) (writePtr >> 32), (uint32) writePtr,
500  numflush, (uint32) (flushPtr >> 32), (uint32) flushPtr,
501  numapply, (uint32) (applyPtr >> 32), (uint32) applyPtr);
502 }
static bool SyncRepGetSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, bool *am_sync)
Definition: syncrep.c:515
#define DEBUG3
Definition: elog.h:23
#define SYNC_REP_PRIORITY
Definition: syncrep.h:36
uint8 syncrep_method
Definition: syncrep.h:51
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
#define LOG
Definition: elog.h:26
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
static int SyncRepWakeQueue(bool all, int mode)
Definition: syncrep.c:973
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
XLogRecPtr flush
#define SYNC_REP_WAIT_APPLY
Definition: syncrep.h:26
static bool announce_next_takeover
Definition: syncrep.c:95
WalSndState state
unsigned int uint32
Definition: c.h:268
#define ereport(elevel, rest)
Definition: elog.h:122
#define SYNC_REP_WAIT_FLUSH
Definition: syncrep.h:25
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
WalSnd * MyWalSnd
Definition: walsender.c:108
uint64 XLogRecPtr
Definition: xlogdefs.h:21
int sync_standby_priority
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
XLogRecPtr lsn[NUM_SYNC_REP_WAIT_MODE]
char * application_name
Definition: guc.c:469
int errmsg(const char *fmt,...)
Definition: elog.c:797
#define elog
Definition: elog.h:219
#define SYNC_REP_WAIT_WRITE
Definition: syncrep.h:24
void SyncRepUpdateSyncStandbysDefined ( void  )

Definition at line 1034 of file syncrep.c.

References i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), NUM_SYNC_REP_WAIT_MODE, WalSndCtlData::sync_standbys_defined, SyncRepWakeQueue(), SyncStandbysDefined, and WalSndCtl.

Referenced by UpdateSharedMemoryConfig().

1035 {
1036  bool sync_standbys_defined = SyncStandbysDefined();
1037 
1038  if (sync_standbys_defined != WalSndCtl->sync_standbys_defined)
1039  {
1040  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
1041 
1042  /*
1043  * If synchronous_standby_names has been reset to empty, it's futile
1044  * for backends to continue to waiting. Since the user no longer
1045  * wants synchronous replication, we'd better wake them up.
1046  */
1047  if (!sync_standbys_defined)
1048  {
1049  int i;
1050 
1051  for (i = 0; i < NUM_SYNC_REP_WAIT_MODE; i++)
1052  SyncRepWakeQueue(true, i);
1053  }
1054 
1055  /*
1056  * Only allow people to join the queue when there are synchronous
1057  * standbys defined. Without this interlock, there's a race
1058  * condition: we might wake up all the current waiters; then, some
1059  * backend that hasn't yet reloaded its config might go to sleep on
1060  * the queue (and never wake up). This prevents that.
1061  */
1062  WalSndCtl->sync_standbys_defined = sync_standbys_defined;
1063 
1064  LWLockRelease(SyncRepLock);
1065  }
1066 }
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
static int SyncRepWakeQueue(bool all, int mode)
Definition: syncrep.c:973
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
#define SyncStandbysDefined()
Definition: syncrep.c:92
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
int i
#define NUM_SYNC_REP_WAIT_MODE
Definition: syncrep.h:28
void SyncRepWaitForLSN ( XLogRecPtr  lsn,
bool  commit 
)

Definition at line 146 of file syncrep.c.

References Assert, DestNone, ereport, errcode(), errdetail(), errmsg(), get_ps_display(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), Min, MyLatch, MyProc, NULL, palloc(), pfree(), PostmasterIsAlive(), ProcDiePending, QueryCancelPending, ResetLatch(), set_ps_display(), SHMQueueIsDetached(), SYNC_REP_NOT_WAITING, SYNC_REP_WAIT_COMPLETE, SYNC_REP_WAIT_FLUSH, SYNC_REP_WAITING, WalSndCtlData::sync_standbys_defined, SyncRepCancelWait(), PGPROC::syncRepLinks, SyncRepQueueInsert(), SyncRepRequested, PGPROC::syncRepState, SyncRepWaitMode, SyncStandbysDefined, update_process_title, WAIT_EVENT_SYNC_REP, WaitLatch(), PGPROC::waitLSN, WalSndCtl, WARNING, whereToSendOutput, WL_LATCH_SET, and WL_POSTMASTER_DEATH.

Referenced by EndPrepare(), RecordTransactionAbortPrepared(), RecordTransactionCommit(), and RecordTransactionCommitPrepared().

147 {
148  char *new_status = NULL;
149  const char *old_status;
150  int mode;
151 
152  /* Cap the level for anything other than commit to remote flush only. */
153  if (commit)
154  mode = SyncRepWaitMode;
155  else
157 
158  /*
159  * Fast exit if user has not requested sync replication, or there are no
160  * sync replication standby names defined. Note that those standbys don't
161  * need to be connected.
162  */
164  return;
165 
167  Assert(WalSndCtl != NULL);
168 
169  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
171 
172  /*
173  * We don't wait for sync rep if WalSndCtl->sync_standbys_defined is not
174  * set. See SyncRepUpdateSyncStandbysDefined.
175  *
176  * Also check that the standby hasn't already replied. Unlikely race
177  * condition but we'll be fetching that cache line anyway so it's likely
178  * to be a low cost check.
179  */
181  lsn <= WalSndCtl->lsn[mode])
182  {
183  LWLockRelease(SyncRepLock);
184  return;
185  }
186 
187  /*
188  * Set our waitLSN so WALSender will know when to wake us, and add
189  * ourselves to the queue.
190  */
191  MyProc->waitLSN = lsn;
193  SyncRepQueueInsert(mode);
194  Assert(SyncRepQueueIsOrderedByLSN(mode));
195  LWLockRelease(SyncRepLock);
196 
197  /* Alter ps display to show waiting for sync rep. */
199  {
200  int len;
201 
202  old_status = get_ps_display(&len);
203  new_status = (char *) palloc(len + 32 + 1);
204  memcpy(new_status, old_status, len);
205  sprintf(new_status + len, " waiting for %X/%X",
206  (uint32) (lsn >> 32), (uint32) lsn);
207  set_ps_display(new_status, false);
208  new_status[len] = '\0'; /* truncate off " waiting ..." */
209  }
210 
211  /*
212  * Wait for specified LSN to be confirmed.
213  *
214  * Each proc has its own wait latch, so we perform a normal latch
215  * check/wait loop here.
216  */
217  for (;;)
218  {
219  /* Must reset the latch before testing state. */
221 
222  /*
223  * Acquiring the lock is not needed, the latch ensures proper
224  * barriers. If it looks like we're done, we must really be done,
225  * because once walsender changes the state to SYNC_REP_WAIT_COMPLETE,
226  * it will never update it again, so we can't be seeing a stale value
227  * in that case.
228  */
230  break;
231 
232  /*
233  * If a wait for synchronous replication is pending, we can neither
234  * acknowledge the commit nor raise ERROR or FATAL. The latter would
235  * lead the client to believe that the transaction aborted, which is
236  * not true: it's already committed locally. The former is no good
237  * either: the client has requested synchronous replication, and is
238  * entitled to assume that an acknowledged commit is also replicated,
239  * which might not be true. So in this case we issue a WARNING (which
240  * some clients may be able to interpret) and shut off further output.
241  * We do NOT reset ProcDiePending, so that the process will die after
242  * the commit is cleaned up.
243  */
244  if (ProcDiePending)
245  {
247  (errcode(ERRCODE_ADMIN_SHUTDOWN),
248  errmsg("canceling the wait for synchronous replication and terminating connection due to administrator command"),
249  errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
252  break;
253  }
254 
255  /*
256  * It's unclear what to do if a query cancel interrupt arrives. We
257  * can't actually abort at this point, but ignoring the interrupt
258  * altogether is not helpful, so we just terminate the wait with a
259  * suitable warning.
260  */
261  if (QueryCancelPending)
262  {
263  QueryCancelPending = false;
265  (errmsg("canceling wait for synchronous replication due to user request"),
266  errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
268  break;
269  }
270 
271  /*
272  * If the postmaster dies, we'll probably never get an
273  * acknowledgement, because all the wal sender processes will exit. So
274  * just bail out.
275  */
276  if (!PostmasterIsAlive())
277  {
278  ProcDiePending = true;
281  break;
282  }
283 
284  /*
285  * Wait on latch. Any condition that should wake us up will set the
286  * latch, so no need for timeout.
287  */
290  }
291 
292  /*
293  * WalSender has checked our LSN and has removed us from queue. Clean up
294  * state and leave. It's OK to reset these shared memory fields without
295  * holding SyncRepLock, because any walsenders will ignore us anyway when
296  * we're not on the queue.
297  */
300  MyProc->waitLSN = 0;
301 
302  if (new_status)
303  {
304  /* Reset ps display */
305  set_ps_display(new_status, false);
306  pfree(new_status);
307  }
308 }
static void SyncRepCancelWait(void)
Definition: syncrep.c:350
bool update_process_title
Definition: ps_status.c:35
static void SyncRepQueueInsert(int mode)
Definition: syncrep.c:317
PGPROC * MyProc
Definition: proc.c:67
#define SYNC_REP_WAITING
Definition: syncrep.h:32
#define Min(x, y)
Definition: c.h:806
void set_ps_display(const char *activity, bool force)
Definition: ps_status.c:326
#define SYNC_REP_NOT_WAITING
Definition: syncrep.h:31
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
int errcode(int sqlerrcode)
Definition: elog.c:575
void ResetLatch(volatile Latch *latch)
Definition: latch.c:498
volatile bool QueryCancelPending
Definition: globals.c:30
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:336
void pfree(void *pointer)
Definition: mcxt.c:950
Definition: dest.h:88
const char * get_ps_display(int *displen)
Definition: ps_status.c:405
#define SyncStandbysDefined()
Definition: syncrep.c:92
bool PostmasterIsAlive(void)
Definition: pmsignal.c:272
int errdetail(const char *fmt,...)
Definition: elog.c:873
unsigned int uint32
Definition: c.h:268
#define ereport(elevel, rest)
Definition: elog.h:122
#define SYNC_REP_WAIT_FLUSH
Definition: syncrep.h:25
#define SyncRepRequested()
Definition: syncrep.h:19
#define WARNING
Definition: elog.h:40
#define WL_POSTMASTER_DEATH
Definition: latch.h:128
#define SYNC_REP_WAIT_COMPLETE
Definition: syncrep.h:33
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
bool SHMQueueIsDetached(const SHM_QUEUE *queue)
Definition: shmqueue.c:47
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1111
SHM_QUEUE syncRepLinks
Definition: proc.h:149
volatile bool ProcDiePending
Definition: globals.c:31
void * palloc(Size size)
Definition: mcxt.c:849
int errmsg(const char *fmt,...)
Definition: elog.c:797
struct Latch * MyLatch
Definition: globals.c:51
int syncRepState
Definition: proc.h:148
CommandDest whereToSendOutput
Definition: postgres.c:86
static int SyncRepWaitMode
Definition: syncrep.c:98
#define WL_LATCH_SET
Definition: latch.h:124
XLogRecPtr waitLSN
Definition: proc.h:147
static int SyncRepWakeQueue ( bool  all,
int  mode 
)
static

Definition at line 973 of file syncrep.c.

References Assert, WalSndCtlData::lsn, NULL, NUM_SYNC_REP_WAIT_MODE, offsetof, PGPROC::procLatch, SetLatch(), SHMQueueDelete(), SHMQueueNext(), SYNC_REP_WAIT_COMPLETE, PGPROC::syncRepLinks, WalSndCtlData::SyncRepQueue, PGPROC::syncRepState, PGPROC::waitLSN, and WalSndCtl.

Referenced by SyncRepReleaseWaiters(), and SyncRepUpdateSyncStandbysDefined().

974 {
975  volatile WalSndCtlData *walsndctl = WalSndCtl;
976  PGPROC *proc = NULL;
977  PGPROC *thisproc = NULL;
978  int numprocs = 0;
979 
980  Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);
981  Assert(SyncRepQueueIsOrderedByLSN(mode));
982 
983  proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
984  &(WalSndCtl->SyncRepQueue[mode]),
985  offsetof(PGPROC, syncRepLinks));
986 
987  while (proc)
988  {
989  /*
990  * Assume the queue is ordered by LSN
991  */
992  if (!all && walsndctl->lsn[mode] < proc->waitLSN)
993  return numprocs;
994 
995  /*
996  * Move to next proc, so we can delete thisproc from the queue.
997  * thisproc is valid, proc may be NULL after this.
998  */
999  thisproc = proc;
1000  proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
1001  &(proc->syncRepLinks),
1002  offsetof(PGPROC, syncRepLinks));
1003 
1004  /*
1005  * Set state to complete; see SyncRepWaitForLSN() for discussion of
1006  * the various states.
1007  */
1009 
1010  /*
1011  * Remove thisproc from queue.
1012  */
1013  SHMQueueDelete(&(thisproc->syncRepLinks));
1014 
1015  /*
1016  * Wake only when we have set state and removed from queue.
1017  */
1018  SetLatch(&(thisproc->procLatch));
1019 
1020  numprocs++;
1021  }
1022 
1023  return numprocs;
1024 }
WalSndCtlData * WalSndCtl
Definition: walsender.c:105
Latch procLatch
Definition: proc.h:103
SHM_QUEUE SyncRepQueue[NUM_SYNC_REP_WAIT_MODE]
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
#define SYNC_REP_WAIT_COMPLETE
Definition: syncrep.h:33
void SetLatch(volatile Latch *latch)
Definition: latch.c:415
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
SHM_QUEUE syncRepLinks
Definition: proc.h:149
XLogRecPtr lsn[NUM_SYNC_REP_WAIT_MODE]
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68
#define NUM_SYNC_REP_WAIT_MODE
Definition: syncrep.h:28
int syncRepState
Definition: proc.h:148
Definition: proc.h:94
XLogRecPtr waitLSN
Definition: proc.h:147
#define offsetof(type, field)
Definition: c.h:555

Variable Documentation

bool announce_next_takeover = true
static

Definition at line 95 of file syncrep.c.

Referenced by SyncRepReleaseWaiters().

SyncRepConfigData* SyncRepConfig = NULL

Definition at line 97 of file syncrep.c.

Referenced by pg_stat_get_wal_senders().

char* SyncRepStandbyNames

Definition at line 90 of file syncrep.c.

int SyncRepWaitMode = SYNC_REP_NO_WAIT
static

Definition at line 98 of file syncrep.c.

Referenced by assign_synchronous_commit(), and SyncRepWaitForLSN().