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syncrep.h File Reference
#include "access/xlogdefs.h"
#include "utils/guc.h"
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Data Structures

struct  SyncRepConfigData
 

Macros

#define SyncRepRequested()   (max_wal_senders > 0 && synchronous_commit > SYNCHRONOUS_COMMIT_LOCAL_FLUSH)
 
#define SYNC_REP_NO_WAIT   (-1)
 
#define SYNC_REP_WAIT_WRITE   0
 
#define SYNC_REP_WAIT_FLUSH   1
 
#define SYNC_REP_WAIT_APPLY   2
 
#define NUM_SYNC_REP_WAIT_MODE   3
 
#define SYNC_REP_NOT_WAITING   0
 
#define SYNC_REP_WAITING   1
 
#define SYNC_REP_WAIT_COMPLETE   2
 
#define SYNC_REP_PRIORITY   0
 
#define SYNC_REP_QUORUM   1
 

Typedefs

typedef struct SyncRepConfigData SyncRepConfigData
 

Functions

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)
 
int syncrep_yyparse (void)
 
int syncrep_yylex (void)
 
void syncrep_yyerror (const char *str)
 
void syncrep_scanner_init (const char *query_string)
 
void syncrep_scanner_finish (void)
 

Variables

SyncRepConfigDataSyncRepConfig
 
SyncRepConfigDatasyncrep_parse_result
 
char * syncrep_parse_error_msg
 
char * SyncRepStandbyNames
 

Macro Definition Documentation

◆ NUM_SYNC_REP_WAIT_MODE

#define NUM_SYNC_REP_WAIT_MODE   3

◆ SYNC_REP_NO_WAIT

#define SYNC_REP_NO_WAIT   (-1)

Definition at line 23 of file syncrep.h.

Referenced by assign_synchronous_commit().

◆ SYNC_REP_NOT_WAITING

#define SYNC_REP_NOT_WAITING   0

Definition at line 31 of file syncrep.h.

Referenced by InitProcess(), SyncRepCancelWait(), and SyncRepWaitForLSN().

◆ SYNC_REP_PRIORITY

◆ SYNC_REP_QUORUM

#define SYNC_REP_QUORUM   1

Definition at line 37 of file syncrep.h.

Referenced by SyncRepGetSyncStandbysQuorum().

◆ SYNC_REP_WAIT_APPLY

#define SYNC_REP_WAIT_APPLY   2

◆ SYNC_REP_WAIT_COMPLETE

#define SYNC_REP_WAIT_COMPLETE   2

Definition at line 33 of file syncrep.h.

Referenced by SyncRepWaitForLSN(), and SyncRepWakeQueue().

◆ SYNC_REP_WAIT_FLUSH

#define SYNC_REP_WAIT_FLUSH   1

◆ SYNC_REP_WAIT_WRITE

#define SYNC_REP_WAIT_WRITE   0

◆ SYNC_REP_WAITING

#define SYNC_REP_WAITING   1

Definition at line 32 of file syncrep.h.

Referenced by SyncRepWaitForLSN().

◆ SyncRepRequested

#define SyncRepRequested ( )    (max_wal_senders > 0 && synchronous_commit > SYNCHRONOUS_COMMIT_LOCAL_FLUSH)

Definition at line 19 of file syncrep.h.

Referenced by SyncRepWaitForLSN().

Typedef Documentation

◆ SyncRepConfigData

Function Documentation

◆ assign_synchronous_commit()

void assign_synchronous_commit ( int  newval,
void *  extra 
)

Definition at line 1201 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.

1202 {
1203  switch (newval)
1204  {
1207  break;
1210  break;
1213  break;
1214  default:
1216  break;
1217  }
1218 }
#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

◆ assign_synchronous_standby_names()

void assign_synchronous_standby_names ( const char *  newval,
void *  extra 
)

Definition at line 1195 of file syncrep.c.

1196 {
1197  SyncRepConfig = (SyncRepConfigData *) extra;
1198 }
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97

◆ check_synchronous_standby_names()

bool check_synchronous_standby_names ( char **  newval,
void **  extra,
GucSource  source 
)

Definition at line 1138 of file syncrep.c.

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

1139 {
1140  if (*newval != NULL && (*newval)[0] != '\0')
1141  {
1142  int parse_rc;
1143  SyncRepConfigData *pconf;
1144 
1145  /* Reset communication variables to ensure a fresh start */
1146  syncrep_parse_result = NULL;
1147  syncrep_parse_error_msg = NULL;
1148 
1149  /* Parse the synchronous_standby_names string */
1151  parse_rc = syncrep_yyparse();
1153 
1154  if (parse_rc != 0 || syncrep_parse_result == NULL)
1155  {
1156  GUC_check_errcode(ERRCODE_SYNTAX_ERROR);
1159  else
1160  GUC_check_errdetail("synchronous_standby_names parser failed");
1161  return false;
1162  }
1163 
1164  if (syncrep_parse_result->num_sync <= 0)
1165  {
1166  GUC_check_errmsg("number of synchronous standbys (%d) must be greater than zero",
1168  return false;
1169  }
1170 
1171  /* GUC extra value must be malloc'd, not palloc'd */
1172  pconf = (SyncRepConfigData *)
1174  if (pconf == NULL)
1175  return false;
1177 
1178  *extra = (void *) pconf;
1179 
1180  /*
1181  * We need not explicitly clean up syncrep_parse_result. It, and any
1182  * other cruft generated during parsing, will be freed when the
1183  * current memory context is deleted. (This code is generally run in
1184  * a short-lived context used for config file processing, so that will
1185  * not be very long.)
1186  */
1187  }
1188  else
1189  *extra = NULL;
1190 
1191  return true;
1192 }
void syncrep_scanner_finish(void)
void syncrep_scanner_init(const char *query_string)
#define GUC_check_errdetail
Definition: guc.h:410
char * syncrep_parse_error_msg
#define GUC_check_errmsg
Definition: guc.h:406
void GUC_check_errcode(int sqlerrcode)
Definition: guc.c:10034
#define malloc(a)
Definition: header.h:50
SyncRepConfigData * syncrep_parse_result
#define newval
int syncrep_yyparse(void)

◆ syncrep_scanner_finish()

void syncrep_scanner_finish ( void  )

◆ syncrep_scanner_init()

void syncrep_scanner_init ( const char *  query_string)

◆ syncrep_yyerror()

void syncrep_yyerror ( const char *  str)

◆ syncrep_yylex()

int syncrep_yylex ( void  )

◆ syncrep_yyparse()

int syncrep_yyparse ( void  )

◆ SyncRepCleanupAtProcExit()

void SyncRepCleanupAtProcExit ( void  )

Definition at line 361 of file syncrep.c.

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

Referenced by ProcKill().

362 {
364  {
365  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
367  LWLockRelease(SyncRepLock);
368  }
369 }
PGPROC * MyProc
Definition: proc.c:67
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
bool SHMQueueIsDetached(const SHM_QUEUE *queue)
Definition: shmqueue.c:47
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
SHM_QUEUE syncRepLinks
Definition: proc.h:150
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68

◆ SyncRepGetSyncStandbys()

List* SyncRepGetSyncStandbys ( bool am_sync)

Definition at line 678 of file syncrep.c.

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

Referenced by pg_stat_get_wal_senders(), and SyncRepGetSyncRecPtr().

679 {
680  /* Set default result */
681  if (am_sync != NULL)
682  *am_sync = false;
683 
684  /* Quick exit if sync replication is not requested */
685  if (SyncRepConfig == NULL)
686  return NIL;
687 
691 }
#define NIL
Definition: pg_list.h:69
static List * SyncRepGetSyncStandbysPriority(bool *am_sync)
Definition: syncrep.c:769
#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:704

◆ SyncRepInitConfig()

void SyncRepInitConfig ( void  )

Definition at line 382 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().

383 {
384  int priority;
385 
386  /*
387  * Determine if we are a potential sync standby and remember the result
388  * for handling replies from standby.
389  */
390  priority = SyncRepGetStandbyPriority();
391  if (MyWalSnd->sync_standby_priority != priority)
392  {
393  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
394  MyWalSnd->sync_standby_priority = priority;
395  LWLockRelease(SyncRepLock);
396  ereport(DEBUG1,
397  (errmsg("standby \"%s\" now has synchronous standby priority %u",
398  application_name, priority)));
399  }
400 }
#define DEBUG1
Definition: elog.h:25
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
#define ereport(elevel, rest)
Definition: elog.h:122
WalSnd * MyWalSnd
Definition: walsender.c:112
int sync_standby_priority
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
char * application_name
Definition: guc.c:472
int errmsg(const char *fmt,...)
Definition: elog.c:797
static int SyncRepGetStandbyPriority(void)
Definition: syncrep.c:947

◆ SyncRepReleaseWaiters()

void SyncRepReleaseWaiters ( void  )

Definition at line 410 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().

411 {
412  volatile WalSndCtlData *walsndctl = WalSndCtl;
413  XLogRecPtr writePtr;
414  XLogRecPtr flushPtr;
415  XLogRecPtr applyPtr;
416  bool got_recptr;
417  bool am_sync;
418  int numwrite = 0;
419  int numflush = 0;
420  int numapply = 0;
421 
422  /*
423  * If this WALSender is serving a standby that is not on the list of
424  * potential sync standbys then we have nothing to do. If we are still
425  * starting up, still running base backup or the current flush position is
426  * still invalid, then leave quickly also.
427  */
428  if (MyWalSnd->sync_standby_priority == 0 ||
431  {
432  announce_next_takeover = true;
433  return;
434  }
435 
436  /*
437  * We're a potential sync standby. Release waiters if there are enough
438  * sync standbys and we are considered as sync.
439  */
440  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
441 
442  /*
443  * Check whether we are a sync standby or not, and calculate the synced
444  * positions among all sync standbys.
445  */
446  got_recptr = SyncRepGetSyncRecPtr(&writePtr, &flushPtr, &applyPtr, &am_sync);
447 
448  /*
449  * If we are managing a sync standby, though we weren't prior to this,
450  * then announce we are now a sync standby.
451  */
452  if (announce_next_takeover && am_sync)
453  {
454  announce_next_takeover = false;
455 
457  ereport(LOG,
458  (errmsg("standby \"%s\" is now a synchronous standby with priority %u",
460  else
461  ereport(LOG,
462  (errmsg("standby \"%s\" is now a candidate for quorum synchronous standby",
463  application_name)));
464  }
465 
466  /*
467  * If the number of sync standbys is less than requested or we aren't
468  * managing a sync standby then just leave.
469  */
470  if (!got_recptr || !am_sync)
471  {
472  LWLockRelease(SyncRepLock);
473  announce_next_takeover = !am_sync;
474  return;
475  }
476 
477  /*
478  * Set the lsn first so that when we wake backends they will release up to
479  * this location.
480  */
481  if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
482  {
483  walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
484  numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
485  }
486  if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
487  {
488  walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
489  numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
490  }
491  if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
492  {
493  walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
494  numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
495  }
496 
497  LWLockRelease(SyncRepLock);
498 
499  elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X, %d procs up to apply %X/%X",
500  numwrite, (uint32) (writePtr >> 32), (uint32) writePtr,
501  numflush, (uint32) (flushPtr >> 32), (uint32) flushPtr,
502  numapply, (uint32) (applyPtr >> 32), (uint32) applyPtr);
503 }
static bool SyncRepGetSyncRecPtr(XLogRecPtr *writePtr, XLogRecPtr *flushPtr, XLogRecPtr *applyPtr, bool *am_sync)
Definition: syncrep.c:516
#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:109
#define LOG
Definition: elog.h:26
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
static int SyncRepWakeQueue(bool all, int mode)
Definition: syncrep.c:994
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
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:325
#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:112
uint64 XLogRecPtr
Definition: xlogdefs.h:21
int sync_standby_priority
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
XLogRecPtr lsn[NUM_SYNC_REP_WAIT_MODE]
char * application_name
Definition: guc.c:472
int errmsg(const char *fmt,...)
Definition: elog.c:797
#define elog
Definition: elog.h:219
#define SYNC_REP_WAIT_WRITE
Definition: syncrep.h:24

◆ SyncRepUpdateSyncStandbysDefined()

void SyncRepUpdateSyncStandbysDefined ( void  )

Definition at line 1062 of file syncrep.c.

References Assert, i, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), NUM_SYNC_REP_WAIT_MODE, offsetof, SHMQueueNext(), WalSndCtlData::sync_standbys_defined, PGPROC::syncRepLinks, WalSndCtlData::SyncRepQueue, SyncRepWakeQueue(), SyncStandbysDefined, PGPROC::waitLSN, and WalSndCtl.

Referenced by UpdateSharedMemoryConfig().

1063 {
1064  bool sync_standbys_defined = SyncStandbysDefined();
1065 
1066  if (sync_standbys_defined != WalSndCtl->sync_standbys_defined)
1067  {
1068  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
1069 
1070  /*
1071  * If synchronous_standby_names has been reset to empty, it's futile
1072  * for backends to continue to waiting. Since the user no longer
1073  * wants synchronous replication, we'd better wake them up.
1074  */
1075  if (!sync_standbys_defined)
1076  {
1077  int i;
1078 
1079  for (i = 0; i < NUM_SYNC_REP_WAIT_MODE; i++)
1080  SyncRepWakeQueue(true, i);
1081  }
1082 
1083  /*
1084  * Only allow people to join the queue when there are synchronous
1085  * standbys defined. Without this interlock, there's a race
1086  * condition: we might wake up all the current waiters; then, some
1087  * backend that hasn't yet reloaded its config might go to sleep on
1088  * the queue (and never wake up). This prevents that.
1089  */
1090  WalSndCtl->sync_standbys_defined = sync_standbys_defined;
1091 
1092  LWLockRelease(SyncRepLock);
1093  }
1094 }
WalSndCtlData * WalSndCtl
Definition: walsender.c:109
static int SyncRepWakeQueue(bool all, int mode)
Definition: syncrep.c:994
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
#define SyncStandbysDefined()
Definition: syncrep.c:92
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
int i
#define NUM_SYNC_REP_WAIT_MODE
Definition: syncrep.h:28

◆ SyncRepWaitForLSN()

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, palloc(), pfree(), pg_read_barrier, 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, 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.
160  */
161  if (!SyncRepRequested())
162  return;
163 
165  Assert(WalSndCtl != NULL);
166 
167  LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
169 
170  /*
171  * We don't wait for sync rep if WalSndCtl->sync_standbys_defined is not
172  * set. See SyncRepUpdateSyncStandbysDefined.
173  *
174  * Also check that the standby hasn't already replied. Unlikely race
175  * condition but we'll be fetching that cache line anyway so it's likely
176  * to be a low cost check.
177  */
179  lsn <= WalSndCtl->lsn[mode])
180  {
181  LWLockRelease(SyncRepLock);
182  return;
183  }
184 
185  /*
186  * Set our waitLSN so WALSender will know when to wake us, and add
187  * ourselves to the queue.
188  */
189  MyProc->waitLSN = lsn;
191  SyncRepQueueInsert(mode);
192  Assert(SyncRepQueueIsOrderedByLSN(mode));
193  LWLockRelease(SyncRepLock);
194 
195  /* Alter ps display to show waiting for sync rep. */
197  {
198  int len;
199 
200  old_status = get_ps_display(&len);
201  new_status = (char *) palloc(len + 32 + 1);
202  memcpy(new_status, old_status, len);
203  sprintf(new_status + len, " waiting for %X/%X",
204  (uint32) (lsn >> 32), (uint32) lsn);
205  set_ps_display(new_status, false);
206  new_status[len] = '\0'; /* truncate off " waiting ..." */
207  }
208 
209  /*
210  * Wait for specified LSN to be confirmed.
211  *
212  * Each proc has its own wait latch, so we perform a normal latch
213  * check/wait loop here.
214  */
215  for (;;)
216  {
217  /* Must reset the latch before testing state. */
219 
220  /*
221  * Acquiring the lock is not needed, the latch ensures proper
222  * barriers. If it looks like we're done, we must really be done,
223  * because once walsender changes the state to SYNC_REP_WAIT_COMPLETE,
224  * it will never update it again, so we can't be seeing a stale value
225  * in that case.
226  */
228  break;
229 
230  /*
231  * If a wait for synchronous replication is pending, we can neither
232  * acknowledge the commit nor raise ERROR or FATAL. The latter would
233  * lead the client to believe that the transaction aborted, which is
234  * not true: it's already committed locally. The former is no good
235  * either: the client has requested synchronous replication, and is
236  * entitled to assume that an acknowledged commit is also replicated,
237  * which might not be true. So in this case we issue a WARNING (which
238  * some clients may be able to interpret) and shut off further output.
239  * We do NOT reset ProcDiePending, so that the process will die after
240  * the commit is cleaned up.
241  */
242  if (ProcDiePending)
243  {
245  (errcode(ERRCODE_ADMIN_SHUTDOWN),
246  errmsg("canceling the wait for synchronous replication and terminating connection due to administrator command"),
247  errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
250  break;
251  }
252 
253  /*
254  * It's unclear what to do if a query cancel interrupt arrives. We
255  * can't actually abort at this point, but ignoring the interrupt
256  * altogether is not helpful, so we just terminate the wait with a
257  * suitable warning.
258  */
259  if (QueryCancelPending)
260  {
261  QueryCancelPending = false;
263  (errmsg("canceling wait for synchronous replication due to user request"),
264  errdetail("The transaction has already committed locally, but might not have been replicated to the standby.")));
266  break;
267  }
268 
269  /*
270  * If the postmaster dies, we'll probably never get an
271  * acknowledgement, because all the wal sender processes will exit. So
272  * just bail out.
273  */
274  if (!PostmasterIsAlive())
275  {
276  ProcDiePending = true;
279  break;
280  }
281 
282  /*
283  * Wait on latch. Any condition that should wake us up will set the
284  * latch, so no need for timeout.
285  */
288  }
289 
290  /*
291  * WalSender has checked our LSN and has removed us from queue. Clean up
292  * state and leave. It's OK to reset these shared memory fields without
293  * holding SyncRepLock, because any walsenders will ignore us anyway when
294  * we're not on the queue. We need a read barrier to make sure we see the
295  * changes to the queue link (this might be unnecessary without
296  * assertions, but better safe than sorry).
297  */
298  pg_read_barrier();
301  MyProc->waitLSN = 0;
302 
303  if (new_status)
304  {
305  /* Reset ps display */
306  set_ps_display(new_status, false);
307  pfree(new_status);
308  }
309 }
static void SyncRepCancelWait(void)
Definition: syncrep.c:351
bool update_process_title
Definition: ps_status.c:35
static void SyncRepQueueInsert(int mode)
Definition: syncrep.c:318
PGPROC * MyProc
Definition: proc.c:67
#define SYNC_REP_WAITING
Definition: syncrep.h:32
#define Min(x, y)
Definition: c.h:857
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:109
int errcode(int sqlerrcode)
Definition: elog.c:575
void ResetLatch(volatile Latch *latch)
Definition: latch.c:497
volatile bool QueryCancelPending
Definition: globals.c:33
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1725
int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:336
void pfree(void *pointer)
Definition: mcxt.c:1031
Definition: dest.h:88
const char * get_ps_display(int *displen)
Definition: ps_status.c:405
bool PostmasterIsAlive(void)
Definition: pmsignal.c:272
int errdetail(const char *fmt,...)
Definition: elog.c:873
unsigned int uint32
Definition: c.h:325
#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 Assert(condition)
Definition: c.h:699
#define pg_read_barrier()
Definition: atomics.h:161
bool SHMQueueIsDetached(const SHM_QUEUE *queue)
Definition: shmqueue.c:47
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1121
SHM_QUEUE syncRepLinks
Definition: proc.h:150
volatile bool ProcDiePending
Definition: globals.c:34
void * palloc(Size size)
Definition: mcxt.c:924
int errmsg(const char *fmt,...)
Definition: elog.c:797
struct Latch * MyLatch
Definition: globals.c:55
int syncRepState
Definition: proc.h:149
CommandDest whereToSendOutput
Definition: postgres.c:89
static int SyncRepWaitMode
Definition: syncrep.c:98
#define WL_LATCH_SET
Definition: latch.h:124
XLogRecPtr waitLSN
Definition: proc.h:148

Variable Documentation

◆ syncrep_parse_error_msg

char* syncrep_parse_error_msg

◆ syncrep_parse_result

SyncRepConfigData* syncrep_parse_result

◆ SyncRepConfig

SyncRepConfigData* SyncRepConfig

Definition at line 97 of file syncrep.c.

Referenced by pg_stat_get_wal_senders().

◆ SyncRepStandbyNames

char* SyncRepStandbyNames

Definition at line 90 of file syncrep.c.