PostgreSQL Source Code  git master
proc.c File Reference
#include "postgres.h"
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include "access/transam.h"
#include "access/twophase.h"
#include "access/xlogutils.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/autovacuum.h"
#include "replication/slot.h"
#include "replication/syncrep.h"
#include "replication/walsender.h"
#include "storage/condition_variable.h"
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "storage/procsignal.h"
#include "storage/spin.h"
#include "storage/standby.h"
#include "utils/timeout.h"
#include "utils/timestamp.h"
Include dependency graph for proc.c:

Go to the source code of this file.

Functions

static void RemoveProcFromArray (int code, Datum arg)
 
static void ProcKill (int code, Datum arg)
 
static void AuxiliaryProcKill (int code, Datum arg)
 
static void CheckDeadLock (void)
 
Size ProcGlobalShmemSize (void)
 
int ProcGlobalSemas (void)
 
void InitProcGlobal (void)
 
void InitProcess (void)
 
void InitProcessPhase2 (void)
 
void InitAuxiliaryProcess (void)
 
void SetStartupBufferPinWaitBufId (int bufid)
 
int GetStartupBufferPinWaitBufId (void)
 
bool HaveNFreeProcs (int n)
 
bool IsWaitingForLock (void)
 
void LockErrorCleanup (void)
 
void ProcReleaseLocks (bool isCommit)
 
PGPROCAuxiliaryPidGetProc (int pid)
 
void ProcQueueInit (PROC_QUEUE *queue)
 
ProcWaitStatus ProcSleep (LOCALLOCK *locallock, LockMethod lockMethodTable)
 
PGPROCProcWakeup (PGPROC *proc, ProcWaitStatus waitStatus)
 
void ProcLockWakeup (LockMethod lockMethodTable, LOCK *lock)
 
void CheckDeadLockAlert (void)
 
void ProcWaitForSignal (uint32 wait_event_info)
 
void ProcSendSignal (int pgprocno)
 
void BecomeLockGroupLeader (void)
 
bool BecomeLockGroupMember (PGPROC *leader, int pid)
 

Variables

int DeadlockTimeout = 1000
 
int StatementTimeout = 0
 
int LockTimeout = 0
 
int IdleInTransactionSessionTimeout = 0
 
int IdleSessionTimeout = 0
 
bool log_lock_waits = false
 
PGPROCMyProc = NULL
 
NON_EXEC_STATIC slock_tProcStructLock = NULL
 
PROC_HDRProcGlobal = NULL
 
NON_EXEC_STATIC PGPROCAuxiliaryProcs = NULL
 
PGPROCPreparedXactProcs = NULL
 
static LOCALLOCKlockAwaited = NULL
 
static DeadLockState deadlock_state = DS_NOT_YET_CHECKED
 
static volatile sig_atomic_t got_deadlock_timeout
 

Function Documentation

◆ AuxiliaryPidGetProc()

PGPROC* AuxiliaryPidGetProc ( int  pid)

Definition at line 968 of file proc.c.

969 {
970  PGPROC *result = NULL;
971  int index;
972 
973  if (pid == 0) /* never match dummy PGPROCs */
974  return NULL;
975 
976  for (index = 0; index < NUM_AUXILIARY_PROCS; index++)
977  {
978  PGPROC *proc = &AuxiliaryProcs[index];
979 
980  if (proc->pid == pid)
981  {
982  result = proc;
983  break;
984  }
985  }
986  return result;
987 }
#define NUM_AUXILIARY_PROCS
Definition: proc.h:412
NON_EXEC_STATIC PGPROC * AuxiliaryProcs
Definition: proc.c:81
Definition: proc.h:160
int pid
Definition: proc.h:184
Definition: type.h:90

References AuxiliaryProcs, NUM_AUXILIARY_PROCS, and PGPROC::pid.

Referenced by pg_log_backend_memory_contexts(), and pg_stat_get_activity().

◆ AuxiliaryProcKill()

static void AuxiliaryProcKill ( int  code,
Datum  arg 
)
static

Definition at line 924 of file proc.c.

925 {
926  int proctype = DatumGetInt32(arg);
928  PGPROC *proc;
929 
930  Assert(proctype >= 0 && proctype < NUM_AUXILIARY_PROCS);
931 
932  auxproc = &AuxiliaryProcs[proctype];
933 
934  Assert(MyProc == auxproc);
935 
936  /* Release any LW locks I am holding (see notes above) */
938 
939  /* Cancel any pending condition variable sleep, too */
941 
942  /* look at the equivalent ProcKill() code for comments */
945 
946  proc = MyProc;
947  MyProc = NULL;
948  DisownLatch(&proc->procLatch);
949 
951 
952  /* Mark auxiliary proc no longer in use */
953  proc->pid = 0;
954 
955  /* Update shared estimate of spins_per_delay */
957 
959 }
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:166
void ConditionVariableCancelSleep(void)
void DisownLatch(Latch *latch)
Definition: latch.c:448
Assert(fmt[strlen(fmt) - 1] !='\n')
void LWLockReleaseAll(void)
Definition: lwlock.c:1899
void SwitchBackToLocalLatch(void)
Definition: miscinit.c:234
void * arg
#define DatumGetInt32(X)
Definition: postgres.h:516
int update_spins_per_delay(int shared_spins_per_delay)
Definition: s_lock.c:207
#define SpinLockRelease(lock)
Definition: spin.h:64
#define SpinLockAcquire(lock)
Definition: spin.h:62
PGPROC * MyProc
Definition: proc.c:68
PROC_HDR * ProcGlobal
Definition: proc.c:80
NON_EXEC_STATIC slock_t * ProcStructLock
Definition: proc.c:77
Latch procLatch
Definition: proc.h:168
int spins_per_delay
Definition: proc.h:392
void pgstat_reset_wait_event_storage(void)
Definition: wait_event.c:62

References arg, Assert(), AuxiliaryProcs, ConditionVariableCancelSleep(), DatumGetInt32, DisownLatch(), LWLockReleaseAll(), MyProc, NUM_AUXILIARY_PROCS, PG_USED_FOR_ASSERTS_ONLY, pgstat_reset_wait_event_storage(), PGPROC::pid, ProcGlobal, PGPROC::procLatch, ProcStructLock, SpinLockAcquire, SpinLockRelease, PROC_HDR::spins_per_delay, SwitchBackToLocalLatch(), and update_spins_per_delay().

Referenced by InitAuxiliaryProcess().

◆ BecomeLockGroupLeader()

void BecomeLockGroupLeader ( void  )

Definition at line 1900 of file proc.c.

1901 {
1902  LWLock *leader_lwlock;
1903 
1904  /* If we already did it, we don't need to do it again. */
1905  if (MyProc->lockGroupLeader == MyProc)
1906  return;
1907 
1908  /* We had better not be a follower. */
1909  Assert(MyProc->lockGroupLeader == NULL);
1910 
1911  /* Create single-member group, containing only ourselves. */
1912  leader_lwlock = LockHashPartitionLockByProc(MyProc);
1913  LWLockAcquire(leader_lwlock, LW_EXCLUSIVE);
1916  LWLockRelease(leader_lwlock);
1917 }
static void dlist_push_head(dlist_head *head, dlist_node *node)
Definition: ilist.h:300
#define LockHashPartitionLockByProc(leader_pgproc)
Definition: lock.h:534
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1196
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1800
@ LW_EXCLUSIVE
Definition: lwlock.h:104
Definition: lwlock.h:32
dlist_head lockGroupMembers
Definition: proc.h:290
dlist_node lockGroupLink
Definition: proc.h:291
PGPROC * lockGroupLeader
Definition: proc.h:289

References Assert(), dlist_push_head(), PGPROC::lockGroupLeader, PGPROC::lockGroupLink, PGPROC::lockGroupMembers, LockHashPartitionLockByProc, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), and MyProc.

Referenced by LaunchParallelWorkers().

◆ BecomeLockGroupMember()

bool BecomeLockGroupMember ( PGPROC leader,
int  pid 
)

Definition at line 1930 of file proc.c.

1931 {
1932  LWLock *leader_lwlock;
1933  bool ok = false;
1934 
1935  /* Group leader can't become member of group */
1936  Assert(MyProc != leader);
1937 
1938  /* Can't already be a member of a group */
1939  Assert(MyProc->lockGroupLeader == NULL);
1940 
1941  /* PID must be valid. */
1942  Assert(pid != 0);
1943 
1944  /*
1945  * Get lock protecting the group fields. Note LockHashPartitionLockByProc
1946  * accesses leader->pgprocno in a PGPROC that might be free. This is safe
1947  * because all PGPROCs' pgprocno fields are set during shared memory
1948  * initialization and never change thereafter; so we will acquire the
1949  * correct lock even if the leader PGPROC is in process of being recycled.
1950  */
1951  leader_lwlock = LockHashPartitionLockByProc(leader);
1952  LWLockAcquire(leader_lwlock, LW_EXCLUSIVE);
1953 
1954  /* Is this the leader we're looking for? */
1955  if (leader->pid == pid && leader->lockGroupLeader == leader)
1956  {
1957  /* OK, join the group */
1958  ok = true;
1959  MyProc->lockGroupLeader = leader;
1961  }
1962  LWLockRelease(leader_lwlock);
1963 
1964  return ok;
1965 }
static void dlist_push_tail(dlist_head *head, dlist_node *node)
Definition: ilist.h:317

References Assert(), dlist_push_tail(), PGPROC::lockGroupLeader, PGPROC::lockGroupLink, PGPROC::lockGroupMembers, LockHashPartitionLockByProc, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, and PGPROC::pid.

Referenced by ParallelWorkerMain().

◆ CheckDeadLock()

static void CheckDeadLock ( void  )
static

Definition at line 1761 of file proc.c.

1762 {
1763  int i;
1764 
1765  /*
1766  * Acquire exclusive lock on the entire shared lock data structures. Must
1767  * grab LWLocks in partition-number order to avoid LWLock deadlock.
1768  *
1769  * Note that the deadlock check interrupt had better not be enabled
1770  * anywhere that this process itself holds lock partition locks, else this
1771  * will wait forever. Also note that LWLockAcquire creates a critical
1772  * section, so that this routine cannot be interrupted by cancel/die
1773  * interrupts.
1774  */
1775  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
1777 
1778  /*
1779  * Check to see if we've been awoken by anyone in the interim.
1780  *
1781  * If we have, we can return and resume our transaction -- happy day.
1782  * Before we are awoken the process releasing the lock grants it to us so
1783  * we know that we don't have to wait anymore.
1784  *
1785  * We check by looking to see if we've been unlinked from the wait queue.
1786  * This is safe because we hold the lock partition lock.
1787  */
1788  if (MyProc->links.prev == NULL ||
1789  MyProc->links.next == NULL)
1790  goto check_done;
1791 
1792 #ifdef LOCK_DEBUG
1793  if (Debug_deadlocks)
1794  DumpAllLocks();
1795 #endif
1796 
1797  /* Run the deadlock check, and set deadlock_state for use by ProcSleep */
1799 
1801  {
1802  /*
1803  * Oops. We have a deadlock.
1804  *
1805  * Get this process out of wait state. (Note: we could do this more
1806  * efficiently by relying on lockAwaited, but use this coding to
1807  * preserve the flexibility to kill some other transaction than the
1808  * one detecting the deadlock.)
1809  *
1810  * RemoveFromWaitQueue sets MyProc->waitStatus to
1811  * PROC_WAIT_STATUS_ERROR, so ProcSleep will report an error after we
1812  * return from the signal handler.
1813  */
1814  Assert(MyProc->waitLock != NULL);
1816 
1817  /*
1818  * We're done here. Transaction abort caused by the error that
1819  * ProcSleep will raise will cause any other locks we hold to be
1820  * released, thus allowing other processes to wake up; we don't need
1821  * to do that here. NOTE: an exception is that releasing locks we
1822  * hold doesn't consider the possibility of waiters that were blocked
1823  * behind us on the lock we just failed to get, and might now be
1824  * wakable because we're not in front of them anymore. However,
1825  * RemoveFromWaitQueue took care of waking up any such processes.
1826  */
1827  }
1828 
1829  /*
1830  * And release locks. We do this in reverse order for two reasons: (1)
1831  * Anyone else who needs more than one of the locks will be trying to lock
1832  * them in increasing order; we don't want to release the other process
1833  * until it can get all the locks it needs. (2) This avoids O(N^2)
1834  * behavior inside LWLockRelease.
1835  */
1836 check_done:
1837  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
1839 }
DeadLockState DeadLockCheck(PGPROC *proc)
Definition: deadlock.c:217
int i
Definition: isn.c:73
void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
Definition: lock.c:1918
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:517
@ DS_HARD_DEADLOCK
Definition: lock.h:506
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:522
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:87
static DeadLockState deadlock_state
Definition: proc.c:87
LOCKTAG tag
Definition: lock.h:303
SHM_QUEUE links
Definition: proc.h:162
LOCK * waitLock
Definition: proc.h:217
struct SHM_QUEUE * next
Definition: shmem.h:31
struct SHM_QUEUE * prev
Definition: shmem.h:30

References Assert(), deadlock_state, DeadLockCheck(), DS_HARD_DEADLOCK, i, PGPROC::links, LockHashPartitionLockByIndex, LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, SHM_QUEUE::next, NUM_LOCK_PARTITIONS, SHM_QUEUE::prev, RemoveFromWaitQueue(), LOCK::tag, and PGPROC::waitLock.

Referenced by ProcSleep().

◆ CheckDeadLockAlert()

void CheckDeadLockAlert ( void  )

Definition at line 1847 of file proc.c.

1848 {
1849  int save_errno = errno;
1850 
1851  got_deadlock_timeout = true;
1852 
1853  /*
1854  * Have to set the latch again, even if handle_sig_alarm already did. Back
1855  * then got_deadlock_timeout wasn't yet set... It's unlikely that this
1856  * ever would be a problem, but setting a set latch again is cheap.
1857  *
1858  * Note that, when this function runs inside procsignal_sigusr1_handler(),
1859  * the handler function sets the latch again after the latch is set here.
1860  */
1861  SetLatch(MyLatch);
1862  errno = save_errno;
1863 }
struct Latch * MyLatch
Definition: globals.c:58
void SetLatch(Latch *latch)
Definition: latch.c:591
static volatile sig_atomic_t got_deadlock_timeout
Definition: proc.c:90

References got_deadlock_timeout, MyLatch, and SetLatch().

Referenced by InitPostgres(), and RecoveryConflictInterrupt().

◆ GetStartupBufferPinWaitBufId()

int GetStartupBufferPinWaitBufId ( void  )

Definition at line 645 of file proc.c.

646 {
647  /* use volatile pointer to prevent code rearrangement */
648  volatile PROC_HDR *procglobal = ProcGlobal;
649 
650  return procglobal->startupBufferPinWaitBufId;
651 }
Definition: proc.h:354
int startupBufferPinWaitBufId
Definition: proc.h:394

References ProcGlobal, and PROC_HDR::startupBufferPinWaitBufId.

Referenced by HoldingBufferPinThatDelaysRecovery(), and RecoveryConflictInterrupt().

◆ HaveNFreeProcs()

bool HaveNFreeProcs ( int  n)

Definition at line 659 of file proc.c.

660 {
661  PGPROC *proc;
662 
664 
665  proc = ProcGlobal->freeProcs;
666 
667  while (n > 0 && proc != NULL)
668  {
669  proc = (PGPROC *) proc->links.next;
670  n--;
671  }
672 
674 
675  return (n <= 0);
676 }
PGPROC * freeProcs
Definition: proc.h:376

References PROC_HDR::freeProcs, PGPROC::links, SHM_QUEUE::next, ProcGlobal, ProcStructLock, SpinLockAcquire, and SpinLockRelease.

Referenced by InitPostgres().

◆ InitAuxiliaryProcess()

void InitAuxiliaryProcess ( void  )

Definition at line 515 of file proc.c.

516 {
517  PGPROC *auxproc;
518  int proctype;
519 
520  /*
521  * ProcGlobal should be set up already (if we are a backend, we inherit
522  * this by fork() or EXEC_BACKEND mechanism from the postmaster).
523  */
524  if (ProcGlobal == NULL || AuxiliaryProcs == NULL)
525  elog(PANIC, "proc header uninitialized");
526 
527  if (MyProc != NULL)
528  elog(ERROR, "you already exist");
529 
530  /*
531  * We use the ProcStructLock to protect assignment and releasing of
532  * AuxiliaryProcs entries.
533  *
534  * While we are holding the ProcStructLock, also copy the current shared
535  * estimate of spins_per_delay to local storage.
536  */
538 
540 
541  /*
542  * Find a free auxproc ... *big* trouble if there isn't one ...
543  */
544  for (proctype = 0; proctype < NUM_AUXILIARY_PROCS; proctype++)
545  {
546  auxproc = &AuxiliaryProcs[proctype];
547  if (auxproc->pid == 0)
548  break;
549  }
550  if (proctype >= NUM_AUXILIARY_PROCS)
551  {
553  elog(FATAL, "all AuxiliaryProcs are in use");
554  }
555 
556  /* Mark auxiliary proc as in use by me */
557  /* use volatile pointer to prevent code rearrangement */
558  ((volatile PGPROC *) auxproc)->pid = MyProcPid;
559 
560  MyProc = auxproc;
561 
563 
564  /*
565  * Initialize all fields of MyProc, except for those previously
566  * initialized by InitProcGlobal.
567  */
571  MyProc->fpVXIDLock = false;
580  MyProc->delayChkptFlags = 0;
581  MyProc->statusFlags = 0;
582  MyProc->lwWaiting = false;
583  MyProc->lwWaitMode = 0;
584  MyProc->waitLock = NULL;
585  MyProc->waitProcLock = NULL;
587 #ifdef USE_ASSERT_CHECKING
588  {
589  int i;
590 
591  /* Last process should have released all locks. */
592  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
594  }
595 #endif
596 
597  /*
598  * Acquire ownership of the PGPROC's latch, so that we can use WaitLatch
599  * on it. That allows us to repoint the process latch, which so far
600  * points to process local one, to the shared one.
601  */
604 
605  /* now that we have a proc, report wait events to shared memory */
607 
608  /* Check that group locking fields are in a proper initial state. */
609  Assert(MyProc->lockGroupLeader == NULL);
611 
612  /*
613  * We might be reusing a semaphore that belonged to a failed process. So
614  * be careful and reinitialize its value here. (This is not strictly
615  * necessary anymore, but seems like a good idea for cleanliness.)
616  */
618 
619  /*
620  * Arrange to clean up at process exit.
621  */
623 }
static void pg_atomic_write_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
Definition: atomics.h:438
#define InvalidBackendId
Definition: backendid.h:23
#define FATAL
Definition: elog.h:35
#define PANIC
Definition: elog.h:36
#define ERROR
Definition: elog.h:33
#define elog(elevel,...)
Definition: elog.h:218
int MyProcPid
Definition: globals.c:44
bool IsBackgroundWorker
Definition: globals.c:115
static bool dlist_is_empty(dlist_head *head)
Definition: ilist.h:289
void on_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:361
void OwnLatch(Latch *latch)
Definition: latch.c:422
#define InvalidLocalTransactionId
Definition: lock.h:70
void SwitchToSharedLatch(void)
Definition: miscinit.c:214
void PGSemaphoreReset(PGSemaphore sema)
Definition: posix_sema.c:295
#define Int32GetDatum(X)
Definition: postgres.h:523
#define InvalidOid
Definition: postgres_ext.h:36
@ PROC_WAIT_STATUS_OK
Definition: proc.h:122
void set_spins_per_delay(int shared_spins_per_delay)
Definition: s_lock.c:196
void SHMQueueElemInit(SHM_QUEUE *queue)
Definition: shmqueue.c:57
bool SHMQueueEmpty(const SHM_QUEUE *queue)
Definition: shmqueue.c:180
static void AuxiliaryProcKill(int code, Datum arg)
Definition: proc.c:924
TransactionId xmin
Definition: proc.h:176
LocalTransactionId lxid
Definition: proc.h:181
PROCLOCK * waitProcLock
Definition: proc.h:218
uint8 lwWaitMode
Definition: proc.h:209
uint32 wait_event_info
Definition: proc.h:264
uint8 statusFlags
Definition: proc.h:227
Oid databaseId
Definition: proc.h:192
pg_atomic_uint64 waitStart
Definition: proc.h:222
bool fpVXIDLock
Definition: proc.h:281
BackendId backendId
Definition: proc.h:191
bool isBackgroundWorker
Definition: proc.h:198
TransactionId xid
Definition: proc.h:171
bool lwWaiting
Definition: proc.h:208
int delayChkptFlags
Definition: proc.h:225
LocalTransactionId fpLocalTransactionId
Definition: proc.h:282
PGSemaphore sem
Definition: proc.h:165
Oid roleId
Definition: proc.h:193
ProcWaitStatus waitStatus
Definition: proc.h:166
Oid tempNamespaceId
Definition: proc.h:195
SHM_QUEUE myProcLocks[NUM_LOCK_PARTITIONS]
Definition: proc.h:246
#define InvalidTransactionId
Definition: transam.h:31
void pgstat_set_wait_event_storage(uint32 *wait_event_info)
Definition: wait_event.c:50

References Assert(), AuxiliaryProcKill(), AuxiliaryProcs, PGPROC::backendId, PGPROC::databaseId, PGPROC::delayChkptFlags, dlist_is_empty(), elog, ERROR, FATAL, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, i, Int32GetDatum, InvalidBackendId, InvalidLocalTransactionId, InvalidOid, InvalidTransactionId, IsBackgroundWorker, PGPROC::isBackgroundWorker, PGPROC::links, PGPROC::lockGroupLeader, PGPROC::lockGroupMembers, PGPROC::lwWaiting, PGPROC::lwWaitMode, PGPROC::lxid, MyProc, PGPROC::myProcLocks, MyProcPid, NUM_AUXILIARY_PROCS, NUM_LOCK_PARTITIONS, on_shmem_exit(), OwnLatch(), PANIC, pg_atomic_write_u64(), PGSemaphoreReset(), pgstat_set_wait_event_storage(), PGPROC::pid, PROC_WAIT_STATUS_OK, ProcGlobal, PGPROC::procLatch, ProcStructLock, PGPROC::roleId, PGPROC::sem, set_spins_per_delay(), SHMQueueElemInit(), SHMQueueEmpty(), SpinLockAcquire, SpinLockRelease, PROC_HDR::spins_per_delay, PGPROC::statusFlags, SwitchToSharedLatch(), PGPROC::tempNamespaceId, PGPROC::wait_event_info, PGPROC::waitLock, PGPROC::waitProcLock, PGPROC::waitStart, PGPROC::waitStatus, PGPROC::xid, and PGPROC::xmin.

Referenced by AuxiliaryProcessMain().

◆ InitProcess()

void InitProcess ( void  )

Definition at line 301 of file proc.c.

302 {
303  PGPROC *volatile *procgloballist;
304 
305  /*
306  * ProcGlobal should be set up already (if we are a backend, we inherit
307  * this by fork() or EXEC_BACKEND mechanism from the postmaster).
308  */
309  if (ProcGlobal == NULL)
310  elog(PANIC, "proc header uninitialized");
311 
312  if (MyProc != NULL)
313  elog(ERROR, "you already exist");
314 
315  /* Decide which list should supply our PGPROC. */
317  procgloballist = &ProcGlobal->autovacFreeProcs;
318  else if (IsBackgroundWorker)
319  procgloballist = &ProcGlobal->bgworkerFreeProcs;
320  else if (am_walsender)
321  procgloballist = &ProcGlobal->walsenderFreeProcs;
322  else
323  procgloballist = &ProcGlobal->freeProcs;
324 
325  /*
326  * Try to get a proc struct from the appropriate free list. If this
327  * fails, we must be out of PGPROC structures (not to mention semaphores).
328  *
329  * While we are holding the ProcStructLock, also copy the current shared
330  * estimate of spins_per_delay to local storage.
331  */
333 
335 
336  MyProc = *procgloballist;
337 
338  if (MyProc != NULL)
339  {
340  *procgloballist = (PGPROC *) MyProc->links.next;
342  }
343  else
344  {
345  /*
346  * If we reach here, all the PGPROCs are in use. This is one of the
347  * possible places to detect "too many backends", so give the standard
348  * error message. XXX do we need to give a different failure message
349  * in the autovacuum case?
350  */
352  if (am_walsender)
353  ereport(FATAL,
354  (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
355  errmsg("number of requested standby connections exceeds max_wal_senders (currently %d)",
356  max_wal_senders)));
357  ereport(FATAL,
358  (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
359  errmsg("sorry, too many clients already")));
360  }
361 
362  /*
363  * Cross-check that the PGPROC is of the type we expect; if this were not
364  * the case, it would get returned to the wrong list.
365  */
366  Assert(MyProc->procgloballist == procgloballist);
367 
368  /*
369  * Now that we have a PGPROC, mark ourselves as an active postmaster
370  * child; this is so that the postmaster can detect it if we exit without
371  * cleaning up. (XXX autovac launcher currently doesn't participate in
372  * this; it probably should.)
373  */
376 
377  /*
378  * Initialize all fields of MyProc, except for those previously
379  * initialized by InitProcGlobal.
380  */
384  MyProc->fpVXIDLock = false;
388  MyProc->pid = MyProcPid;
389  /* backendId, databaseId and roleId will be filled in later */
395  MyProc->delayChkptFlags = 0;
396  MyProc->statusFlags = 0;
397  /* NB -- autovac launcher intentionally does not set IS_AUTOVACUUM */
400  MyProc->lwWaiting = false;
401  MyProc->lwWaitMode = 0;
402  MyProc->waitLock = NULL;
403  MyProc->waitProcLock = NULL;
405 #ifdef USE_ASSERT_CHECKING
406  {
407  int i;
408 
409  /* Last process should have released all locks. */
410  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
412  }
413 #endif
415 
416  /* Initialize fields for sync rep */
417  MyProc->waitLSN = 0;
420 
421  /* Initialize fields for group XID clearing. */
422  MyProc->procArrayGroupMember = false;
425 
426  /* Check that group locking fields are in a proper initial state. */
427  Assert(MyProc->lockGroupLeader == NULL);
429 
430  /* Initialize wait event information. */
431  MyProc->wait_event_info = 0;
432 
433  /* Initialize fields for group transaction status update. */
434  MyProc->clogGroupMember = false;
440 
441  /*
442  * Acquire ownership of the PGPROC's latch, so that we can use WaitLatch
443  * on it. That allows us to repoint the process latch, which so far
444  * points to process local one, to the shared one.
445  */
448 
449  /* now that we have a proc, report wait events to shared memory */
451 
452  /*
453  * We might be reusing a semaphore that belonged to a failed process. So
454  * be careful and reinitialize its value here. (This is not strictly
455  * necessary anymore, but seems like a good idea for cleanliness.)
456  */
458 
459  /*
460  * Arrange to clean up at backend exit.
461  */
463 
464  /*
465  * Now that we have a PGPROC, we could try to acquire locks, so initialize
466  * local state needed for LWLocks, and the deadlock checker.
467  */
470 }
static uint32 pg_atomic_read_u32(volatile pg_atomic_uint32 *ptr)
Definition: atomics.h:241
bool IsAutoVacuumLauncherProcess(void)
Definition: autovacuum.c:3303
bool IsAutoVacuumWorkerProcess(void)
Definition: autovacuum.c:3309
#define IsAnyAutoVacuumProcess()
Definition: autovacuum.h:55
#define TRANSACTION_STATUS_IN_PROGRESS
Definition: clog.h:27
void InitDeadLockChecking(void)
Definition: deadlock.c:143
int errcode(int sqlerrcode)
Definition: elog.c:693
int errmsg(const char *fmt,...)
Definition: elog.c:904
#define ereport(elevel,...)
Definition: elog.h:143
bool IsUnderPostmaster
Definition: globals.c:113
void InitLWLockAccess(void)
Definition: lwlock.c:580
void MarkPostmasterChildActive(void)
Definition: pmsignal.c:291
#define INVALID_PGPROCNO
Definition: proc.h:83
#define PROC_IS_AUTOVACUUM
Definition: proc.h:54
static void ProcKill(int code, Datum arg)
Definition: proc.c:803
PGPROC ** procgloballist
Definition: proc.h:163
bool procArrayGroupMember
Definition: proc.h:254
XLogRecPtr clogGroupMemberLsn
Definition: proc.h:274
pg_atomic_uint32 procArrayGroupNext
Definition: proc.h:256
int clogGroupMemberPage
Definition: proc.h:272
bool recoveryConflictPending
Definition: proc.h:205
TransactionId clogGroupMemberXid
Definition: proc.h:269
bool clogGroupMember
Definition: proc.h:267
XLogRecPtr waitLSN
Definition: proc.h:237
int syncRepState
Definition: proc.h:238
pg_atomic_uint32 clogGroupNext
Definition: proc.h:268
SHM_QUEUE syncRepLinks
Definition: proc.h:239
XidStatus clogGroupMemberXidStatus
Definition: proc.h:270
TransactionId procArrayGroupMemberXid
Definition: proc.h:262
PGPROC * walsenderFreeProcs
Definition: proc.h:382
PGPROC * autovacFreeProcs
Definition: proc.h:378
PGPROC * bgworkerFreeProcs
Definition: proc.h:380
#define SYNC_REP_NOT_WAITING
Definition: syncrep.h:31
bool am_walsender
Definition: walsender.c:116
int max_wal_senders
Definition: walsender.c:122
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28

References am_walsender, Assert(), PROC_HDR::autovacFreeProcs, PGPROC::backendId, PROC_HDR::bgworkerFreeProcs, PGPROC::clogGroupMember, PGPROC::clogGroupMemberLsn, PGPROC::clogGroupMemberPage, PGPROC::clogGroupMemberXid, PGPROC::clogGroupMemberXidStatus, PGPROC::clogGroupNext, PGPROC::databaseId, PGPROC::delayChkptFlags, dlist_is_empty(), elog, ereport, errcode(), errmsg(), ERROR, FATAL, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, PROC_HDR::freeProcs, i, InitDeadLockChecking(), InitLWLockAccess(), INVALID_PGPROCNO, InvalidBackendId, InvalidLocalTransactionId, InvalidOid, InvalidTransactionId, InvalidXLogRecPtr, IsAnyAutoVacuumProcess, IsAutoVacuumLauncherProcess(), IsAutoVacuumWorkerProcess(), IsBackgroundWorker, PGPROC::isBackgroundWorker, IsUnderPostmaster, PGPROC::links, PGPROC::lockGroupLeader, PGPROC::lockGroupMembers, PGPROC::lwWaiting, PGPROC::lwWaitMode, PGPROC::lxid, MarkPostmasterChildActive(), max_wal_senders, MyProc, PGPROC::myProcLocks, MyProcPid, SHM_QUEUE::next, NUM_LOCK_PARTITIONS, on_shmem_exit(), OwnLatch(), PANIC, pg_atomic_read_u32(), pg_atomic_write_u64(), PGSemaphoreReset(), pgstat_set_wait_event_storage(), PGPROC::pid, PROC_IS_AUTOVACUUM, PROC_WAIT_STATUS_OK, PGPROC::procArrayGroupMember, PGPROC::procArrayGroupMemberXid, PGPROC::procArrayGroupNext, ProcGlobal, PGPROC::procgloballist, ProcKill(), PGPROC::procLatch, ProcStructLock, PGPROC::recoveryConflictPending, PGPROC::roleId, PGPROC::sem, set_spins_per_delay(), SHMQueueElemInit(), SHMQueueEmpty(), SpinLockAcquire, SpinLockRelease, PROC_HDR::spins_per_delay, PGPROC::statusFlags, SwitchToSharedLatch(), SYNC_REP_NOT_WAITING, PGPROC::syncRepLinks, PGPROC::syncRepState, PGPROC::tempNamespaceId, TRANSACTION_STATUS_IN_PROGRESS, PGPROC::wait_event_info, PGPROC::waitLock, PGPROC::waitLSN, PGPROC::waitProcLock, PGPROC::waitStart, PGPROC::waitStatus, PROC_HDR::walsenderFreeProcs, PGPROC::xid, and PGPROC::xmin.

Referenced by AutoVacLauncherMain(), AutoVacWorkerMain(), BackendStartup(), BootstrapModeMain(), PostgresSingleUserMain(), and StartBackgroundWorker().

◆ InitProcessPhase2()

void InitProcessPhase2 ( void  )

Definition at line 480 of file proc.c.

481 {
482  Assert(MyProc != NULL);
483 
484  /*
485  * Add our PGPROC to the PGPROC array in shared memory.
486  */
488 
489  /*
490  * Arrange to clean that up at backend exit.
491  */
493 }
void ProcArrayAdd(PGPROC *proc)
Definition: procarray.c:460
static void RemoveProcFromArray(int code, Datum arg)
Definition: proc.c:792

References Assert(), MyProc, on_shmem_exit(), ProcArrayAdd(), and RemoveProcFromArray().

Referenced by InitPostgres().

◆ InitProcGlobal()

void InitProcGlobal ( void  )

Definition at line 159 of file proc.c.

160 {
161  PGPROC *procs;
162  int i,
163  j;
164  bool found;
166 
167  /* Create the ProcGlobal shared structure */
168  ProcGlobal = (PROC_HDR *)
169  ShmemInitStruct("Proc Header", sizeof(PROC_HDR), &found);
170  Assert(!found);
171 
172  /*
173  * Initialize the data structures.
174  */
176  ProcGlobal->freeProcs = NULL;
181  ProcGlobal->walwriterLatch = NULL;
185 
186  /*
187  * Create and initialize all the PGPROC structures we'll need. There are
188  * five separate consumers: (1) normal backends, (2) autovacuum workers
189  * and the autovacuum launcher, (3) background workers, (4) auxiliary
190  * processes, and (5) prepared transactions. Each PGPROC structure is
191  * dedicated to exactly one of these purposes, and they do not move
192  * between groups.
193  */
194  procs = (PGPROC *) ShmemAlloc(TotalProcs * sizeof(PGPROC));
195  MemSet(procs, 0, TotalProcs * sizeof(PGPROC));
196  ProcGlobal->allProcs = procs;
197  /* XXX allProcCount isn't really all of them; it excludes prepared xacts */
199 
200  /*
201  * Allocate arrays mirroring PGPROC fields in a dense manner. See
202  * PROC_HDR.
203  *
204  * XXX: It might make sense to increase padding for these arrays, given
205  * how hotly they are accessed.
206  */
207  ProcGlobal->xids =
208  (TransactionId *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->xids));
209  MemSet(ProcGlobal->xids, 0, TotalProcs * sizeof(*ProcGlobal->xids));
211  MemSet(ProcGlobal->subxidStates, 0, TotalProcs * sizeof(*ProcGlobal->subxidStates));
212  ProcGlobal->statusFlags = (uint8 *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->statusFlags));
213  MemSet(ProcGlobal->statusFlags, 0, TotalProcs * sizeof(*ProcGlobal->statusFlags));
214 
215  for (i = 0; i < TotalProcs; i++)
216  {
217  /* Common initialization for all PGPROCs, regardless of type. */
218 
219  /*
220  * Set up per-PGPROC semaphore, latch, and fpInfoLock. Prepared xact
221  * dummy PGPROCs don't need these though - they're never associated
222  * with a real process
223  */
225  {
226  procs[i].sem = PGSemaphoreCreate();
227  InitSharedLatch(&(procs[i].procLatch));
228  LWLockInitialize(&(procs[i].fpInfoLock), LWTRANCHE_LOCK_FASTPATH);
229  }
230  procs[i].pgprocno = i;
231 
232  /*
233  * Newly created PGPROCs for normal backends, autovacuum and bgworkers
234  * must be queued up on the appropriate free list. Because there can
235  * only ever be a small, fixed number of auxiliary processes, no free
236  * list is used in that case; InitAuxiliaryProcess() instead uses a
237  * linear search. PGPROCs for prepared transactions are added to a
238  * free list by TwoPhaseShmemInit().
239  */
240  if (i < MaxConnections)
241  {
242  /* PGPROC for normal backend, add to freeProcs list */
243  procs[i].links.next = (SHM_QUEUE *) ProcGlobal->freeProcs;
244  ProcGlobal->freeProcs = &procs[i];
246  }
247  else if (i < MaxConnections + autovacuum_max_workers + 1)
248  {
249  /* PGPROC for AV launcher/worker, add to autovacFreeProcs list */
251  ProcGlobal->autovacFreeProcs = &procs[i];
253  }
255  {
256  /* PGPROC for bgworker, add to bgworkerFreeProcs list */
258  ProcGlobal->bgworkerFreeProcs = &procs[i];
260  }
261  else if (i < MaxBackends)
262  {
263  /* PGPROC for walsender, add to walsenderFreeProcs list */
265  ProcGlobal->walsenderFreeProcs = &procs[i];
267  }
268 
269  /* Initialize myProcLocks[] shared memory queues. */
270  for (j = 0; j < NUM_LOCK_PARTITIONS; j++)
271  SHMQueueInit(&(procs[i].myProcLocks[j]));
272 
273  /* Initialize lockGroupMembers list. */
274  dlist_init(&procs[i].lockGroupMembers);
275 
276  /*
277  * Initialize the atomic variables, otherwise, it won't be safe to
278  * access them for backends that aren't currently in use.
279  */
280  pg_atomic_init_u32(&(procs[i].procArrayGroupNext), INVALID_PGPROCNO);
281  pg_atomic_init_u32(&(procs[i].clogGroupNext), INVALID_PGPROCNO);
282  pg_atomic_init_u64(&(procs[i].waitStart), 0);
283  }
284 
285  /*
286  * Save pointers to the blocks of PGPROC structures reserved for auxiliary
287  * processes and prepared transactions.
288  */
289  AuxiliaryProcs = &procs[MaxBackends];
291 
292  /* Create ProcStructLock spinlock, too */
293  ProcStructLock = (slock_t *) ShmemAlloc(sizeof(slock_t));
295 }
static void pg_atomic_init_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
Definition: atomics.h:223
static void pg_atomic_init_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
Definition: atomics.h:415
int autovacuum_max_workers
Definition: autovacuum.c:116
unsigned int uint32
Definition: c.h:452
unsigned char uint8
Definition: c.h:450
#define MemSet(start, val, len)
Definition: c.h:1019
uint32 TransactionId
Definition: c.h:598
int MaxConnections
Definition: globals.c:137
int MaxBackends
Definition: globals.c:140
int max_worker_processes
Definition: globals.c:138
static void dlist_init(dlist_head *head)
Definition: ilist.h:278
int j
Definition: isn.c:74
void InitSharedLatch(Latch *latch)
Definition: latch.c:389
void LWLockInitialize(LWLock *lock, int tranche_id)
Definition: lwlock.c:734
@ LWTRANCHE_LOCK_FASTPATH
Definition: lwlock.h:180
PGSemaphore PGSemaphoreCreate(void)
Definition: posix_sema.c:262
#define DEFAULT_SPINS_PER_DELAY
Definition: s_lock.h:1053
int slock_t
Definition: s_lock.h:975
void * ShmemAlloc(Size size)
Definition: shmem.c:161
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:396
void SHMQueueInit(SHM_QUEUE *queue)
Definition: shmqueue.c:36
#define SpinLockInit(lock)
Definition: spin.h:60
PGPROC * PreparedXactProcs
Definition: proc.c:82
int pgprocno
Definition: proc.h:188
uint8 * statusFlags
Definition: proc.h:371
XidCacheStatus * subxidStates
Definition: proc.h:365
Latch * walwriterLatch
Definition: proc.h:388
PGPROC * allProcs
Definition: proc.h:356
pg_atomic_uint32 clogGroupFirst
Definition: proc.h:386
TransactionId * xids
Definition: proc.h:359
Latch * checkpointerLatch
Definition: proc.h:390
pg_atomic_uint32 procArrayGroupFirst
Definition: proc.h:384
uint32 allProcCount
Definition: proc.h:374
int max_prepared_xacts
Definition: twophase.c:117

References PROC_HDR::allProcCount, PROC_HDR::allProcs, Assert(), PROC_HDR::autovacFreeProcs, autovacuum_max_workers, AuxiliaryProcs, PROC_HDR::bgworkerFreeProcs, PROC_HDR::checkpointerLatch, PROC_HDR::clogGroupFirst, DEFAULT_SPINS_PER_DELAY, dlist_init(), PROC_HDR::freeProcs, i, InitSharedLatch(), INVALID_PGPROCNO, j, PGPROC::links, LWLockInitialize(), LWTRANCHE_LOCK_FASTPATH, max_prepared_xacts, max_worker_processes, MaxBackends, MaxConnections, MemSet, SHM_QUEUE::next, NUM_AUXILIARY_PROCS, NUM_LOCK_PARTITIONS, pg_atomic_init_u32(), pg_atomic_init_u64(), PGPROC::pgprocno, PGSemaphoreCreate(), PreparedXactProcs, PROC_HDR::procArrayGroupFirst, ProcGlobal, PGPROC::procgloballist, ProcStructLock, PGPROC::sem, ShmemAlloc(), ShmemInitStruct(), SHMQueueInit(), SpinLockInit, PROC_HDR::spins_per_delay, PROC_HDR::startupBufferPinWaitBufId, PROC_HDR::statusFlags, PROC_HDR::subxidStates, PROC_HDR::walsenderFreeProcs, PROC_HDR::walwriterLatch, and PROC_HDR::xids.

Referenced by CreateSharedMemoryAndSemaphores().

◆ IsWaitingForLock()

bool IsWaitingForLock ( void  )

Definition at line 682 of file proc.c.

683 {
684  if (lockAwaited == NULL)
685  return false;
686 
687  return true;
688 }
static LOCALLOCK * lockAwaited
Definition: proc.c:85

References lockAwaited.

Referenced by RecoveryConflictInterrupt().

◆ LockErrorCleanup()

void LockErrorCleanup ( void  )

Definition at line 699 of file proc.c.

700 {
701  LWLock *partitionLock;
702  DisableTimeoutParams timeouts[2];
703 
704  HOLD_INTERRUPTS();
705 
707 
708  /* Nothing to do if we weren't waiting for a lock */
709  if (lockAwaited == NULL)
710  {
712  return;
713  }
714 
715  /*
716  * Turn off the deadlock and lock timeout timers, if they are still
717  * running (see ProcSleep). Note we must preserve the LOCK_TIMEOUT
718  * indicator flag, since this function is executed before
719  * ProcessInterrupts when responding to SIGINT; else we'd lose the
720  * knowledge that the SIGINT came from a lock timeout and not an external
721  * source.
722  */
723  timeouts[0].id = DEADLOCK_TIMEOUT;
724  timeouts[0].keep_indicator = false;
725  timeouts[1].id = LOCK_TIMEOUT;
726  timeouts[1].keep_indicator = true;
727  disable_timeouts(timeouts, 2);
728 
729  /* Unlink myself from the wait queue, if on it (might not be anymore!) */
730  partitionLock = LockHashPartitionLock(lockAwaited->hashcode);
731  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
732 
733  if (MyProc->links.next != NULL)
734  {
735  /* We could not have been granted the lock yet */
737  }
738  else
739  {
740  /*
741  * Somebody kicked us off the lock queue already. Perhaps they
742  * granted us the lock, or perhaps they detected a deadlock. If they
743  * did grant us the lock, we'd better remember it in our local lock
744  * table.
745  */
748  }
749 
750  lockAwaited = NULL;
751 
752  LWLockRelease(partitionLock);
753 
755 }
void GrantAwaitedLock(void)
Definition: lock.c:1786
void AbortStrongLockAcquire(void)
Definition: lock.c:1757
#define LockHashPartitionLock(hashcode)
Definition: lock.h:519
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:134
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:132
TimeoutId id
Definition: timeout.h:70
uint32 hashcode
Definition: lock.h:424
void disable_timeouts(const DisableTimeoutParams *timeouts, int count)
Definition: timeout.c:722
@ LOCK_TIMEOUT
Definition: timeout.h:28
@ DEADLOCK_TIMEOUT
Definition: timeout.h:27

References AbortStrongLockAcquire(), DEADLOCK_TIMEOUT, disable_timeouts(), GrantAwaitedLock(), LOCALLOCK::hashcode, HOLD_INTERRUPTS, DisableTimeoutParams::id, DisableTimeoutParams::keep_indicator, PGPROC::links, LOCK_TIMEOUT, lockAwaited, LockHashPartitionLock, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, SHM_QUEUE::next, PROC_WAIT_STATUS_OK, RemoveFromWaitQueue(), RESUME_INTERRUPTS, and PGPROC::waitStatus.

Referenced by AbortSubTransaction(), AbortTransaction(), ProcessInterrupts(), and ProcReleaseLocks().

◆ ProcGlobalSemas()

int ProcGlobalSemas ( void  )

Definition at line 124 of file proc.c.

125 {
126  /*
127  * We need a sema per backend (including autovacuum), plus one for each
128  * auxiliary process.
129  */
131 }

References MaxBackends, and NUM_AUXILIARY_PROCS.

Referenced by CalculateShmemSize().

◆ ProcGlobalShmemSize()

Size ProcGlobalShmemSize ( void  )

Definition at line 102 of file proc.c.

103 {
104  Size size = 0;
105  Size TotalProcs =
107 
108  /* ProcGlobal */
109  size = add_size(size, sizeof(PROC_HDR));
110  size = add_size(size, mul_size(TotalProcs, sizeof(PGPROC)));
111  size = add_size(size, sizeof(slock_t));
112 
113  size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->xids)));
114  size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->subxidStates)));
115  size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->statusFlags)));
116 
117  return size;
118 }
size_t Size
Definition: c.h:551
Size add_size(Size s1, Size s2)
Definition: shmem.c:502
Size mul_size(Size s1, Size s2)
Definition: shmem.c:519

References add_size(), max_prepared_xacts, MaxBackends, mul_size(), NUM_AUXILIARY_PROCS, ProcGlobal, PROC_HDR::statusFlags, PROC_HDR::subxidStates, and PROC_HDR::xids.

Referenced by CalculateShmemSize().

◆ ProcKill()

static void ProcKill ( int  code,
Datum  arg 
)
static

Definition at line 803 of file proc.c.

804 {
805  PGPROC *proc;
806  PGPROC *volatile *procgloballist;
807 
808  Assert(MyProc != NULL);
809 
810  /* Make sure we're out of the sync rep lists */
812 
813 #ifdef USE_ASSERT_CHECKING
814  {
815  int i;
816 
817  /* Last process should have released all locks. */
818  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
820  }
821 #endif
822 
823  /*
824  * Release any LW locks I am holding. There really shouldn't be any, but
825  * it's cheap to check again before we cut the knees off the LWLock
826  * facility by releasing our PGPROC ...
827  */
829 
830  /* Cancel any pending condition variable sleep, too */
832 
833  /*
834  * Detach from any lock group of which we are a member. If the leader
835  * exist before all other group members, its PGPROC will remain allocated
836  * until the last group process exits; that process must return the
837  * leader's PGPROC to the appropriate list.
838  */
839  if (MyProc->lockGroupLeader != NULL)
840  {
841  PGPROC *leader = MyProc->lockGroupLeader;
842  LWLock *leader_lwlock = LockHashPartitionLockByProc(leader);
843 
844  LWLockAcquire(leader_lwlock, LW_EXCLUSIVE);
847  if (dlist_is_empty(&leader->lockGroupMembers))
848  {
849  leader->lockGroupLeader = NULL;
850  if (leader != MyProc)
851  {
852  procgloballist = leader->procgloballist;
853 
854  /* Leader exited first; return its PGPROC. */
856  leader->links.next = (SHM_QUEUE *) *procgloballist;
857  *procgloballist = leader;
859  }
860  }
861  else if (leader != MyProc)
862  MyProc->lockGroupLeader = NULL;
863  LWLockRelease(leader_lwlock);
864  }
865 
866  /*
867  * Reset MyLatch to the process local one. This is so that signal
868  * handlers et al can continue using the latch after the shared latch
869  * isn't ours anymore.
870  *
871  * Similarly, stop reporting wait events to MyProc->wait_event_info.
872  *
873  * After that clear MyProc and disown the shared latch.
874  */
877 
878  proc = MyProc;
879  MyProc = NULL;
880  DisownLatch(&proc->procLatch);
881 
882  procgloballist = proc->procgloballist;
884 
885  /*
886  * If we're still a member of a locking group, that means we're a leader
887  * which has somehow exited before its children. The last remaining child
888  * will release our PGPROC. Otherwise, release it now.
889  */
890  if (proc->lockGroupLeader == NULL)
891  {
892  /* Since lockGroupLeader is NULL, lockGroupMembers should be empty. */
894 
895  /* Return PGPROC structure (and semaphore) to appropriate freelist */
896  proc->links.next = (SHM_QUEUE *) *procgloballist;
897  *procgloballist = proc;
898  }
899 
900  /* Update shared estimate of spins_per_delay */
902 
904 
905  /*
906  * This process is no longer present in shared memory in any meaningful
907  * way, so tell the postmaster we've cleaned up acceptably well. (XXX
908  * autovac launcher should be included here someday)
909  */
912 
913  /* wake autovac launcher if needed -- see comments in FreeWorkerInfo */
914  if (AutovacuumLauncherPid != 0)
916 }
int AutovacuumLauncherPid
Definition: autovacuum.c:303
static void dlist_delete(dlist_node *node)
Definition: ilist.h:358
void MarkPostmasterChildInactive(void)
Definition: pmsignal.c:324
void SyncRepCleanupAtProcExit(void)
Definition: syncrep.c:382
#define kill(pid, sig)
Definition: win32_port.h:464
#define SIGUSR2
Definition: win32_port.h:180

References Assert(), AutovacuumLauncherPid, ConditionVariableCancelSleep(), DisownLatch(), dlist_delete(), dlist_is_empty(), i, IsAutoVacuumLauncherProcess(), IsUnderPostmaster, kill, PGPROC::links, PGPROC::lockGroupLeader, PGPROC::lockGroupLink, PGPROC::lockGroupMembers, LockHashPartitionLockByProc, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LWLockReleaseAll(), MarkPostmasterChildInactive(), MyProc, PGPROC::myProcLocks, SHM_QUEUE::next, NUM_LOCK_PARTITIONS, pgstat_reset_wait_event_storage(), ProcGlobal, PGPROC::procgloballist, PGPROC::procLatch, ProcStructLock, SHMQueueEmpty(), SIGUSR2, SpinLockAcquire, SpinLockRelease, PROC_HDR::spins_per_delay, SwitchBackToLocalLatch(), SyncRepCleanupAtProcExit(), and update_spins_per_delay().

Referenced by InitProcess().

◆ ProcLockWakeup()

void ProcLockWakeup ( LockMethod  lockMethodTable,
LOCK lock 
)

Definition at line 1702 of file proc.c.

1703 {
1704  PROC_QUEUE *waitQueue = &(lock->waitProcs);
1705  int queue_size = waitQueue->size;
1706  PGPROC *proc;
1707  LOCKMASK aheadRequests = 0;
1708 
1709  Assert(queue_size >= 0);
1710 
1711  if (queue_size == 0)
1712  return;
1713 
1714  proc = (PGPROC *) waitQueue->links.next;
1715 
1716  while (queue_size-- > 0)
1717  {
1718  LOCKMODE lockmode = proc->waitLockMode;
1719 
1720  /*
1721  * Waken if (a) doesn't conflict with requests of earlier waiters, and
1722  * (b) doesn't conflict with already-held locks.
1723  */
1724  if ((lockMethodTable->conflictTab[lockmode] & aheadRequests) == 0 &&
1725  !LockCheckConflicts(lockMethodTable, lockmode, lock,
1726  proc->waitProcLock))
1727  {
1728  /* OK to waken */
1729  GrantLock(lock, proc->waitProcLock, lockmode);
1730  proc = ProcWakeup(proc, PROC_WAIT_STATUS_OK);
1731 
1732  /*
1733  * ProcWakeup removes proc from the lock's waiting process queue
1734  * and returns the next proc in chain; don't use proc's next-link,
1735  * because it's been cleared.
1736  */
1737  }
1738  else
1739  {
1740  /*
1741  * Cannot wake this guy. Remember his request for later checks.
1742  */
1743  aheadRequests |= LOCKBIT_ON(lockmode);
1744  proc = (PGPROC *) proc->links.next;
1745  }
1746  }
1747 
1748  Assert(waitQueue->size >= 0);
1749 }
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1555
bool LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
Definition: lock.c:1420
#define LOCKBIT_ON(lockmode)
Definition: lock.h:89
int LOCKMODE
Definition: lockdefs.h:26
int LOCKMASK
Definition: lockdefs.h:25
while(p+4<=pend)
PGPROC * ProcWakeup(PGPROC *proc, ProcWaitStatus waitStatus)
Definition: proc.c:1665
PROC_QUEUE waitProcs
Definition: lock.h:309
const LOCKMASK * conflictTab
Definition: lock.h:116
LOCKMODE waitLockMode
Definition: proc.h:219
SHM_QUEUE links
Definition: lock.h:32
int size
Definition: lock.h:33

References Assert(), LockMethodData::conflictTab, GrantLock(), PROC_QUEUE::links, PGPROC::links, LOCKBIT_ON, LockCheckConflicts(), SHM_QUEUE::next, PROC_WAIT_STATUS_OK, ProcWakeup(), PROC_QUEUE::size, PGPROC::waitLockMode, PGPROC::waitProcLock, LOCK::waitProcs, and while().

Referenced by CleanUpLock(), and DeadLockCheck().

◆ ProcQueueInit()

void ProcQueueInit ( PROC_QUEUE queue)

Definition at line 1021 of file proc.c.

1022 {
1023  SHMQueueInit(&(queue->links));
1024  queue->size = 0;
1025 }

References PROC_QUEUE::links, SHMQueueInit(), and PROC_QUEUE::size.

Referenced by DeadLockCheck(), lock_twophase_recover(), and SetupLockInTable().

◆ ProcReleaseLocks()

void ProcReleaseLocks ( bool  isCommit)

Definition at line 775 of file proc.c.

776 {
777  if (!MyProc)
778  return;
779  /* If waiting, get off wait queue (should only be needed after error) */
781  /* Release standard locks, including session-level if aborting */
783  /* Release transaction-level advisory locks */
785 }
void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
Definition: lock.c:2180
#define DEFAULT_LOCKMETHOD
Definition: lock.h:130
#define USER_LOCKMETHOD
Definition: lock.h:131
void LockErrorCleanup(void)
Definition: proc.c:699

References DEFAULT_LOCKMETHOD, LockErrorCleanup(), LockReleaseAll(), MyProc, and USER_LOCKMETHOD.

Referenced by ResourceOwnerReleaseInternal().

◆ ProcSendSignal()

void ProcSendSignal ( int  pgprocno)

Definition at line 1885 of file proc.c.

1886 {
1887  if (pgprocno < 0 || pgprocno >= ProcGlobal->allProcCount)
1888  elog(ERROR, "pgprocno out of range");
1889 
1890  SetLatch(&ProcGlobal->allProcs[pgprocno].procLatch);
1891 }

References PROC_HDR::allProcCount, PROC_HDR::allProcs, elog, ERROR, ProcGlobal, PGPROC::procLatch, and SetLatch().

Referenced by ReleasePredicateLocks(), and UnpinBuffer().

◆ ProcSleep()

ProcWaitStatus ProcSleep ( LOCALLOCK locallock,
LockMethod  lockMethodTable 
)

Definition at line 1045 of file proc.c.

1046 {
1047  LOCKMODE lockmode = locallock->tag.mode;
1048  LOCK *lock = locallock->lock;
1049  PROCLOCK *proclock = locallock->proclock;
1050  uint32 hashcode = locallock->hashcode;
1051  LWLock *partitionLock = LockHashPartitionLock(hashcode);
1052  PROC_QUEUE *waitQueue = &(lock->waitProcs);
1053  LOCKMASK myHeldLocks = MyProc->heldLocks;
1054  TimestampTz standbyWaitStart = 0;
1055  bool early_deadlock = false;
1056  bool allow_autovacuum_cancel = true;
1057  bool logged_recovery_conflict = false;
1058  ProcWaitStatus myWaitStatus;
1059  PGPROC *proc;
1060  PGPROC *leader = MyProc->lockGroupLeader;
1061  int i;
1062 
1063  /*
1064  * If group locking is in use, locks held by members of my locking group
1065  * need to be included in myHeldLocks. This is not required for relation
1066  * extension or page locks which conflict among group members. However,
1067  * including them in myHeldLocks will give group members the priority to
1068  * get those locks as compared to other backends which are also trying to
1069  * acquire those locks. OTOH, we can avoid giving priority to group
1070  * members for that kind of locks, but there doesn't appear to be a clear
1071  * advantage of the same.
1072  */
1073  if (leader != NULL)
1074  {
1075  SHM_QUEUE *procLocks = &(lock->procLocks);
1076  PROCLOCK *otherproclock;
1077 
1078  otherproclock = (PROCLOCK *)
1079  SHMQueueNext(procLocks, procLocks, offsetof(PROCLOCK, lockLink));
1080  while (otherproclock != NULL)
1081  {
1082  if (otherproclock->groupLeader == leader)
1083  myHeldLocks |= otherproclock->holdMask;
1084  otherproclock = (PROCLOCK *)
1085  SHMQueueNext(procLocks, &otherproclock->lockLink,
1086  offsetof(PROCLOCK, lockLink));
1087  }
1088  }
1089 
1090  /*
1091  * Determine where to add myself in the wait queue.
1092  *
1093  * Normally I should go at the end of the queue. However, if I already
1094  * hold locks that conflict with the request of any previous waiter, put
1095  * myself in the queue just in front of the first such waiter. This is not
1096  * a necessary step, since deadlock detection would move me to before that
1097  * waiter anyway; but it's relatively cheap to detect such a conflict
1098  * immediately, and avoid delaying till deadlock timeout.
1099  *
1100  * Special case: if I find I should go in front of some waiter, check to
1101  * see if I conflict with already-held locks or the requests before that
1102  * waiter. If not, then just grant myself the requested lock immediately.
1103  * This is the same as the test for immediate grant in LockAcquire, except
1104  * we are only considering the part of the wait queue before my insertion
1105  * point.
1106  */
1107  if (myHeldLocks != 0)
1108  {
1109  LOCKMASK aheadRequests = 0;
1110 
1111  proc = (PGPROC *) waitQueue->links.next;
1112  for (i = 0; i < waitQueue->size; i++)
1113  {
1114  /*
1115  * If we're part of the same locking group as this waiter, its
1116  * locks neither conflict with ours nor contribute to
1117  * aheadRequests.
1118  */
1119  if (leader != NULL && leader == proc->lockGroupLeader)
1120  {
1121  proc = (PGPROC *) proc->links.next;
1122  continue;
1123  }
1124  /* Must he wait for me? */
1125  if (lockMethodTable->conflictTab[proc->waitLockMode] & myHeldLocks)
1126  {
1127  /* Must I wait for him ? */
1128  if (lockMethodTable->conflictTab[lockmode] & proc->heldLocks)
1129  {
1130  /*
1131  * Yes, so we have a deadlock. Easiest way to clean up
1132  * correctly is to call RemoveFromWaitQueue(), but we
1133  * can't do that until we are *on* the wait queue. So, set
1134  * a flag to check below, and break out of loop. Also,
1135  * record deadlock info for later message.
1136  */
1137  RememberSimpleDeadLock(MyProc, lockmode, lock, proc);
1138  early_deadlock = true;
1139  break;
1140  }
1141  /* I must go before this waiter. Check special case. */
1142  if ((lockMethodTable->conflictTab[lockmode] & aheadRequests) == 0 &&
1143  !LockCheckConflicts(lockMethodTable, lockmode, lock,
1144  proclock))
1145  {
1146  /* Skip the wait and just grant myself the lock. */
1147  GrantLock(lock, proclock, lockmode);
1148  GrantAwaitedLock();
1149  return PROC_WAIT_STATUS_OK;
1150  }
1151  /* Break out of loop to put myself before him */
1152  break;
1153  }
1154  /* Nope, so advance to next waiter */
1155  aheadRequests |= LOCKBIT_ON(proc->waitLockMode);
1156  proc = (PGPROC *) proc->links.next;
1157  }
1158 
1159  /*
1160  * If we fall out of loop normally, proc points to waitQueue head, so
1161  * we will insert at tail of queue as desired.
1162  */
1163  }
1164  else
1165  {
1166  /* I hold no locks, so I can't push in front of anyone. */
1167  proc = (PGPROC *) &(waitQueue->links);
1168  }
1169 
1170  /*
1171  * Insert self into queue, ahead of the given proc (or at tail of queue).
1172  */
1173  SHMQueueInsertBefore(&(proc->links), &(MyProc->links));
1174  waitQueue->size++;
1175 
1176  lock->waitMask |= LOCKBIT_ON(lockmode);
1177 
1178  /* Set up wait information in PGPROC object, too */
1179  MyProc->waitLock = lock;
1180  MyProc->waitProcLock = proclock;
1181  MyProc->waitLockMode = lockmode;
1182 
1184 
1185  /*
1186  * If we detected deadlock, give up without waiting. This must agree with
1187  * CheckDeadLock's recovery code.
1188  */
1189  if (early_deadlock)
1190  {
1191  RemoveFromWaitQueue(MyProc, hashcode);
1192  return PROC_WAIT_STATUS_ERROR;
1193  }
1194 
1195  /* mark that we are waiting for a lock */
1196  lockAwaited = locallock;
1197 
1198  /*
1199  * Release the lock table's partition lock.
1200  *
1201  * NOTE: this may also cause us to exit critical-section state, possibly
1202  * allowing a cancel/die interrupt to be accepted. This is OK because we
1203  * have recorded the fact that we are waiting for a lock, and so
1204  * LockErrorCleanup will clean up if cancel/die happens.
1205  */
1206  LWLockRelease(partitionLock);
1207 
1208  /*
1209  * Also, now that we will successfully clean up after an ereport, it's
1210  * safe to check to see if there's a buffer pin deadlock against the
1211  * Startup process. Of course, that's only necessary if we're doing Hot
1212  * Standby and are not the Startup process ourselves.
1213  */
1214  if (RecoveryInProgress() && !InRecovery)
1216 
1217  /* Reset deadlock_state before enabling the timeout handler */
1219  got_deadlock_timeout = false;
1220 
1221  /*
1222  * Set timer so we can wake up after awhile and check for a deadlock. If a
1223  * deadlock is detected, the handler sets MyProc->waitStatus =
1224  * PROC_WAIT_STATUS_ERROR, allowing us to know that we must report failure
1225  * rather than success.
1226  *
1227  * By delaying the check until we've waited for a bit, we can avoid
1228  * running the rather expensive deadlock-check code in most cases.
1229  *
1230  * If LockTimeout is set, also enable the timeout for that. We can save a
1231  * few cycles by enabling both timeout sources in one call.
1232  *
1233  * If InHotStandby we set lock waits slightly later for clarity with other
1234  * code.
1235  */
1236  if (!InHotStandby)
1237  {
1238  if (LockTimeout > 0)
1239  {
1240  EnableTimeoutParams timeouts[2];
1241 
1242  timeouts[0].id = DEADLOCK_TIMEOUT;
1243  timeouts[0].type = TMPARAM_AFTER;
1244  timeouts[0].delay_ms = DeadlockTimeout;
1245  timeouts[1].id = LOCK_TIMEOUT;
1246  timeouts[1].type = TMPARAM_AFTER;
1247  timeouts[1].delay_ms = LockTimeout;
1248  enable_timeouts(timeouts, 2);
1249  }
1250  else
1252 
1253  /*
1254  * Use the current time obtained for the deadlock timeout timer as
1255  * waitStart (i.e., the time when this process started waiting for the
1256  * lock). Since getting the current time newly can cause overhead, we
1257  * reuse the already-obtained time to avoid that overhead.
1258  *
1259  * Note that waitStart is updated without holding the lock table's
1260  * partition lock, to avoid the overhead by additional lock
1261  * acquisition. This can cause "waitstart" in pg_locks to become NULL
1262  * for a very short period of time after the wait started even though
1263  * "granted" is false. This is OK in practice because we can assume
1264  * that users are likely to look at "waitstart" when waiting for the
1265  * lock for a long time.
1266  */
1269  }
1270  else if (log_recovery_conflict_waits)
1271  {
1272  /*
1273  * Set the wait start timestamp if logging is enabled and in hot
1274  * standby.
1275  */
1276  standbyWaitStart = GetCurrentTimestamp();
1277  }
1278 
1279  /*
1280  * If somebody wakes us between LWLockRelease and WaitLatch, the latch
1281  * will not wait. But a set latch does not necessarily mean that the lock
1282  * is free now, as there are many other sources for latch sets than
1283  * somebody releasing the lock.
1284  *
1285  * We process interrupts whenever the latch has been set, so cancel/die
1286  * interrupts are processed quickly. This means we must not mind losing
1287  * control to a cancel/die interrupt here. We don't, because we have no
1288  * shared-state-change work to do after being granted the lock (the
1289  * grantor did it all). We do have to worry about canceling the deadlock
1290  * timeout and updating the locallock table, but if we lose control to an
1291  * error, LockErrorCleanup will fix that up.
1292  */
1293  do
1294  {
1295  if (InHotStandby)
1296  {
1297  bool maybe_log_conflict =
1298  (standbyWaitStart != 0 && !logged_recovery_conflict);
1299 
1300  /* Set a timer and wait for that or for the lock to be granted */
1302  maybe_log_conflict);
1303 
1304  /*
1305  * Emit the log message if the startup process is waiting longer
1306  * than deadlock_timeout for recovery conflict on lock.
1307  */
1308  if (maybe_log_conflict)
1309  {
1311 
1312  if (TimestampDifferenceExceeds(standbyWaitStart, now,
1313  DeadlockTimeout))
1314  {
1315  VirtualTransactionId *vxids;
1316  int cnt;
1317 
1318  vxids = GetLockConflicts(&locallock->tag.lock,
1319  AccessExclusiveLock, &cnt);
1320 
1321  /*
1322  * Log the recovery conflict and the list of PIDs of
1323  * backends holding the conflicting lock. Note that we do
1324  * logging even if there are no such backends right now
1325  * because the startup process here has already waited
1326  * longer than deadlock_timeout.
1327  */
1329  standbyWaitStart, now,
1330  cnt > 0 ? vxids : NULL, true);
1331  logged_recovery_conflict = true;
1332  }
1333  }
1334  }
1335  else
1336  {
1338  PG_WAIT_LOCK | locallock->tag.lock.locktag_type);
1340  /* check for deadlocks first, as that's probably log-worthy */
1342  {
1343  CheckDeadLock();
1344  got_deadlock_timeout = false;
1345  }
1347  }
1348 
1349  /*
1350  * waitStatus could change from PROC_WAIT_STATUS_WAITING to something
1351  * else asynchronously. Read it just once per loop to prevent
1352  * surprising behavior (such as missing log messages).
1353  */
1354  myWaitStatus = *((volatile ProcWaitStatus *) &MyProc->waitStatus);
1355 
1356  /*
1357  * If we are not deadlocked, but are waiting on an autovacuum-induced
1358  * task, send a signal to interrupt it.
1359  */
1360  if (deadlock_state == DS_BLOCKED_BY_AUTOVACUUM && allow_autovacuum_cancel)
1361  {
1362  PGPROC *autovac = GetBlockingAutoVacuumPgproc();
1363  uint8 statusFlags;
1364  uint8 lockmethod_copy;
1365  LOCKTAG locktag_copy;
1366 
1367  /*
1368  * Grab info we need, then release lock immediately. Note this
1369  * coding means that there is a tiny chance that the process
1370  * terminates its current transaction and starts a different one
1371  * before we have a change to send the signal; the worst possible
1372  * consequence is that a for-wraparound vacuum is cancelled. But
1373  * that could happen in any case unless we were to do kill() with
1374  * the lock held, which is much more undesirable.
1375  */
1376  LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
1377  statusFlags = ProcGlobal->statusFlags[autovac->pgxactoff];
1378  lockmethod_copy = lock->tag.locktag_lockmethodid;
1379  locktag_copy = lock->tag;
1380  LWLockRelease(ProcArrayLock);
1381 
1382  /*
1383  * Only do it if the worker is not working to protect against Xid
1384  * wraparound.
1385  */
1386  if ((statusFlags & PROC_IS_AUTOVACUUM) &&
1387  !(statusFlags & PROC_VACUUM_FOR_WRAPAROUND))
1388  {
1389  int pid = autovac->pid;
1390 
1391  /* report the case, if configured to do so */
1393  {
1394  StringInfoData locktagbuf;
1395  StringInfoData logbuf; /* errdetail for server log */
1396 
1397  initStringInfo(&locktagbuf);
1398  initStringInfo(&logbuf);
1399  DescribeLockTag(&locktagbuf, &locktag_copy);
1400  appendStringInfo(&logbuf,
1401  "Process %d waits for %s on %s.",
1402  MyProcPid,
1403  GetLockmodeName(lockmethod_copy, lockmode),
1404  locktagbuf.data);
1405 
1406  ereport(DEBUG1,
1407  (errmsg_internal("sending cancel to blocking autovacuum PID %d",
1408  pid),
1409  errdetail_log("%s", logbuf.data)));
1410 
1411  pfree(locktagbuf.data);
1412  pfree(logbuf.data);
1413  }
1414 
1415  /* send the autovacuum worker Back to Old Kent Road */
1416  if (kill(pid, SIGINT) < 0)
1417  {
1418  /*
1419  * There's a race condition here: once we release the
1420  * ProcArrayLock, it's possible for the autovac worker to
1421  * close up shop and exit before we can do the kill().
1422  * Therefore, we do not whinge about no-such-process.
1423  * Other errors such as EPERM could conceivably happen if
1424  * the kernel recycles the PID fast enough, but such cases
1425  * seem improbable enough that it's probably best to issue
1426  * a warning if we see some other errno.
1427  */
1428  if (errno != ESRCH)
1429  ereport(WARNING,
1430  (errmsg("could not send signal to process %d: %m",
1431  pid)));
1432  }
1433  }
1434 
1435  /* prevent signal from being sent again more than once */
1436  allow_autovacuum_cancel = false;
1437  }
1438 
1439  /*
1440  * If awoken after the deadlock check interrupt has run, and
1441  * log_lock_waits is on, then report about the wait.
1442  */
1444  {
1446  lock_waiters_sbuf,
1447  lock_holders_sbuf;
1448  const char *modename;
1449  long secs;
1450  int usecs;
1451  long msecs;
1452  SHM_QUEUE *procLocks;
1453  PROCLOCK *proclock;
1454  bool first_holder = true,
1455  first_waiter = true;
1456  int lockHoldersNum = 0;
1457 
1458  initStringInfo(&buf);
1459  initStringInfo(&lock_waiters_sbuf);
1460  initStringInfo(&lock_holders_sbuf);
1461 
1462  DescribeLockTag(&buf, &locallock->tag.lock);
1463  modename = GetLockmodeName(locallock->tag.lock.locktag_lockmethodid,
1464  lockmode);
1467  &secs, &usecs);
1468  msecs = secs * 1000 + usecs / 1000;
1469  usecs = usecs % 1000;
1470 
1471  /*
1472  * we loop over the lock's procLocks to gather a list of all
1473  * holders and waiters. Thus we will be able to provide more
1474  * detailed information for lock debugging purposes.
1475  *
1476  * lock->procLocks contains all processes which hold or wait for
1477  * this lock.
1478  */
1479 
1480  LWLockAcquire(partitionLock, LW_SHARED);
1481 
1482  procLocks = &(lock->procLocks);
1483  proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
1484  offsetof(PROCLOCK, lockLink));
1485 
1486  while (proclock)
1487  {
1488  /*
1489  * we are a waiter if myProc->waitProcLock == proclock; we are
1490  * a holder if it is NULL or something different
1491  */
1492  if (proclock->tag.myProc->waitProcLock == proclock)
1493  {
1494  if (first_waiter)
1495  {
1496  appendStringInfo(&lock_waiters_sbuf, "%d",
1497  proclock->tag.myProc->pid);
1498  first_waiter = false;
1499  }
1500  else
1501  appendStringInfo(&lock_waiters_sbuf, ", %d",
1502  proclock->tag.myProc->pid);
1503  }
1504  else
1505  {
1506  if (first_holder)
1507  {
1508  appendStringInfo(&lock_holders_sbuf, "%d",
1509  proclock->tag.myProc->pid);
1510  first_holder = false;
1511  }
1512  else
1513  appendStringInfo(&lock_holders_sbuf, ", %d",
1514  proclock->tag.myProc->pid);
1515 
1516  lockHoldersNum++;
1517  }
1518 
1519  proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
1520  offsetof(PROCLOCK, lockLink));
1521  }
1522 
1523  LWLockRelease(partitionLock);
1524 
1526  ereport(LOG,
1527  (errmsg("process %d avoided deadlock for %s on %s by rearranging queue order after %ld.%03d ms",
1528  MyProcPid, modename, buf.data, msecs, usecs),
1529  (errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
1530  "Processes holding the lock: %s. Wait queue: %s.",
1531  lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
1532  else if (deadlock_state == DS_HARD_DEADLOCK)
1533  {
1534  /*
1535  * This message is a bit redundant with the error that will be
1536  * reported subsequently, but in some cases the error report
1537  * might not make it to the log (eg, if it's caught by an
1538  * exception handler), and we want to ensure all long-wait
1539  * events get logged.
1540  */
1541  ereport(LOG,
1542  (errmsg("process %d detected deadlock while waiting for %s on %s after %ld.%03d ms",
1543  MyProcPid, modename, buf.data, msecs, usecs),
1544  (errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
1545  "Processes holding the lock: %s. Wait queue: %s.",
1546  lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
1547  }
1548 
1549  if (myWaitStatus == PROC_WAIT_STATUS_WAITING)
1550  ereport(LOG,
1551  (errmsg("process %d still waiting for %s on %s after %ld.%03d ms",
1552  MyProcPid, modename, buf.data, msecs, usecs),
1553  (errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
1554  "Processes holding the lock: %s. Wait queue: %s.",
1555  lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
1556  else if (myWaitStatus == PROC_WAIT_STATUS_OK)
1557  ereport(LOG,
1558  (errmsg("process %d acquired %s on %s after %ld.%03d ms",
1559  MyProcPid, modename, buf.data, msecs, usecs)));
1560  else
1561  {
1562  Assert(myWaitStatus == PROC_WAIT_STATUS_ERROR);
1563 
1564  /*
1565  * Currently, the deadlock checker always kicks its own
1566  * process, which means that we'll only see
1567  * PROC_WAIT_STATUS_ERROR when deadlock_state ==
1568  * DS_HARD_DEADLOCK, and there's no need to print redundant
1569  * messages. But for completeness and future-proofing, print
1570  * a message if it looks like someone else kicked us off the
1571  * lock.
1572  */
1574  ereport(LOG,
1575  (errmsg("process %d failed to acquire %s on %s after %ld.%03d ms",
1576  MyProcPid, modename, buf.data, msecs, usecs),
1577  (errdetail_log_plural("Process holding the lock: %s. Wait queue: %s.",
1578  "Processes holding the lock: %s. Wait queue: %s.",
1579  lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
1580  }
1581 
1582  /*
1583  * At this point we might still need to wait for the lock. Reset
1584  * state so we don't print the above messages again.
1585  */
1587 
1588  pfree(buf.data);
1589  pfree(lock_holders_sbuf.data);
1590  pfree(lock_waiters_sbuf.data);
1591  }
1592  } while (myWaitStatus == PROC_WAIT_STATUS_WAITING);
1593 
1594  /*
1595  * Disable the timers, if they are still running. As in LockErrorCleanup,
1596  * we must preserve the LOCK_TIMEOUT indicator flag: if a lock timeout has
1597  * already caused QueryCancelPending to become set, we want the cancel to
1598  * be reported as a lock timeout, not a user cancel.
1599  */
1600  if (!InHotStandby)
1601  {
1602  if (LockTimeout > 0)
1603  {
1604  DisableTimeoutParams timeouts[2];
1605 
1606  timeouts[0].id = DEADLOCK_TIMEOUT;
1607  timeouts[0].keep_indicator = false;
1608  timeouts[1].id = LOCK_TIMEOUT;
1609  timeouts[1].keep_indicator = true;
1610  disable_timeouts(timeouts, 2);
1611  }
1612  else
1614  }
1615 
1616  /*
1617  * Emit the log message if recovery conflict on lock was resolved but the
1618  * startup process waited longer than deadlock_timeout for it.
1619  */
1620  if (InHotStandby && logged_recovery_conflict)
1622  standbyWaitStart, GetCurrentTimestamp(),
1623  NULL, false);
1624 
1625  /*
1626  * Re-acquire the lock table's partition lock. We have to do this to hold
1627  * off cancel/die interrupts before we can mess with lockAwaited (else we
1628  * might have a missed or duplicated locallock update).
1629  */
1630  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
1631 
1632  /*
1633  * We no longer want LockErrorCleanup to do anything.
1634  */
1635  lockAwaited = NULL;
1636 
1637  /*
1638  * If we got the lock, be sure to remember it in the locallock table.
1639  */
1641  GrantAwaitedLock();
1642 
1643  /*
1644  * We don't have to do anything else, because the awaker did all the
1645  * necessary update of the lock table and MyProc.
1646  */
1647  return MyProc->waitStatus;
1648 }
void TimestampDifference(TimestampTz start_time, TimestampTz stop_time, long *secs, int *microsecs)
Definition: timestamp.c:1650
bool TimestampDifferenceExceeds(TimestampTz start_time, TimestampTz stop_time, int msec)
Definition: timestamp.c:1705
TimestampTz GetCurrentTimestamp(void)
Definition: timestamp.c:1574
Datum now(PG_FUNCTION_ARGS)
Definition: timestamp.c:1538
#define offsetof(type, field)
Definition: c.h:738
int64 TimestampTz
Definition: timestamp.h:39
PGPROC * GetBlockingAutoVacuumPgproc(void)
Definition: deadlock.c:293
void RememberSimpleDeadLock(PGPROC *proc1, LOCKMODE lockmode, LOCK *lock, PGPROC *proc2)
Definition: deadlock.c:1162
int errmsg_internal(const char *fmt,...)
Definition: elog.c:991
bool message_level_is_interesting(int elevel)
Definition: elog.c:265
int errdetail_log_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1106
int errdetail_log(const char *fmt,...)
Definition: elog.c:1085
#define LOG
Definition: elog.h:25
#define WARNING
Definition: elog.h:30
#define DEBUG1
Definition: elog.h:24
void ResetLatch(Latch *latch)
Definition: latch.c:683
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:476
#define WL_EXIT_ON_PM_DEATH
Definition: latch.h:130
#define WL_LATCH_SET
Definition: latch.h:125
void DescribeLockTag(StringInfo buf, const LOCKTAG *tag)
Definition: lmgr.c:1129
VirtualTransactionId * GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp)
Definition: lock.c:2914
const char * GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
Definition: lock.c:4100
@ DS_BLOCKED_BY_AUTOVACUUM
Definition: lock.h:507
@ DS_NO_DEADLOCK
Definition: lock.h:504
@ DS_NOT_YET_CHECKED
Definition: lock.h:503
@ DS_SOFT_DEADLOCK
Definition: lock.h:505
#define AccessExclusiveLock
Definition: lockdefs.h:43
@ LW_SHARED
Definition: lwlock.h:105
void pfree(void *pointer)
Definition: mcxt.c:1175
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121
static char * buf
Definition: pg_test_fsync.c:67
#define PROC_VACUUM_FOR_WRAPAROUND
Definition: proc.h:57
ProcWaitStatus
Definition: proc.h:121
@ PROC_WAIT_STATUS_WAITING
Definition: proc.h:123
@ PROC_WAIT_STATUS_ERROR
Definition: proc.h:124
@ PROCSIG_RECOVERY_CONFLICT_LOCK
Definition: procsignal.h:42
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
void SHMQueueInsertBefore(SHM_QUEUE *queue, SHM_QUEUE *elem)
Definition: shmqueue.c:89
bool log_lock_waits
Definition: proc.c:65
int DeadlockTimeout
Definition: proc.c:60
static void CheckDeadLock(void)
Definition: proc.c:1761
int LockTimeout
Definition: proc.c:62
void CheckRecoveryConflictDeadlock(void)
Definition: standby.c:867
bool log_recovery_conflict_waits
Definition: standby.c:43
void LogRecoveryConflict(ProcSignalReason reason, TimestampTz wait_start, TimestampTz now, VirtualTransactionId *wait_list, bool still_waiting)
Definition: standby.c:251
void ResolveRecoveryConflictWithLock(LOCKTAG locktag, bool logging_conflict)
Definition: standby.c:585
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:91
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59
TimeoutType type
Definition: timeout.h:60
TimeoutId id
Definition: timeout.h:59
LOCKTAG lock
Definition: lock.h:402
LOCKMODE mode
Definition: lock.h:403
LOCK * lock
Definition: lock.h:425
PROCLOCK * proclock
Definition: lock.h:426
LOCALLOCKTAG tag
Definition: lock.h:421
Definition: lock.h:168
uint8 locktag_type
Definition: lock.h:173
uint8 locktag_lockmethodid
Definition: lock.h:174
Definition: lock.h:301
SHM_QUEUE procLocks
Definition: lock.h:308
LOCKMASK waitMask
Definition: lock.h:307
int pgxactoff
Definition: proc.h:186
LOCKMASK heldLocks
Definition: proc.h:220
PGPROC * myProc
Definition: lock.h:358
Definition: lock.h:362
LOCKMASK holdMask
Definition: lock.h:368
PGPROC * groupLeader
Definition: lock.h:367
SHM_QUEUE lockLink
Definition: lock.h:370
PROCLOCKTAG tag
Definition: lock.h:364
void enable_timeout_after(TimeoutId id, int delay_ms)
Definition: timeout.c:564
TimestampTz get_timeout_start_time(TimeoutId id)
Definition: timeout.c:817
void disable_timeout(TimeoutId id, bool keep_indicator)
Definition: timeout.c:689
void enable_timeouts(const EnableTimeoutParams *timeouts, int count)
Definition: timeout.c:634
@ TMPARAM_AFTER
Definition: timeout.h:52
#define PG_WAIT_LOCK
Definition: wait_event.h:19
bool RecoveryInProgress(void)
Definition: xlog.c:5762
bool InRecovery
Definition: xlogutils.c:53
#define InHotStandby
Definition: xlogutils.h:57

References AccessExclusiveLock, appendStringInfo(), Assert(), buf, CHECK_FOR_INTERRUPTS, CheckDeadLock(), CheckRecoveryConflictDeadlock(), LockMethodData::conflictTab, StringInfoData::data, deadlock_state, DEADLOCK_TIMEOUT, DeadlockTimeout, DEBUG1, EnableTimeoutParams::delay_ms, DescribeLockTag(), disable_timeout(), disable_timeouts(), DS_BLOCKED_BY_AUTOVACUUM, DS_HARD_DEADLOCK, DS_NO_DEADLOCK, DS_NOT_YET_CHECKED, DS_SOFT_DEADLOCK, enable_timeout_after(), enable_timeouts(), ereport, errdetail_log(), errdetail_log_plural(), errmsg(), errmsg_internal(), get_timeout_start_time(), GetBlockingAutoVacuumPgproc(), GetCurrentTimestamp(), GetLockConflicts(), GetLockmodeName(), got_deadlock_timeout, GrantAwaitedLock(), GrantLock(), PROCLOCK::groupLeader, LOCALLOCK::hashcode, PGPROC::heldLocks, PROCLOCK::holdMask, i, EnableTimeoutParams::id, DisableTimeoutParams::id, InHotStandby, initStringInfo(), InRecovery, DisableTimeoutParams::keep_indicator, kill, PROC_QUEUE::links, PGPROC::links, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_TIMEOUT, lockAwaited, LOCKBIT_ON, LockCheckConflicts(), PGPROC::lockGroupLeader, LockHashPartitionLock, PROCLOCK::lockLink, LOCKTAG::locktag_lockmethodid, LOCKTAG::locktag_type, LockTimeout, LOG, log_lock_waits, log_recovery_conflict_waits, LogRecoveryConflict(), LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), message_level_is_interesting(), LOCALLOCKTAG::mode, MyLatch, MyProc, PROCLOCKTAG::myProc, MyProcPid, SHM_QUEUE::next, now(), offsetof, pfree(), pg_atomic_write_u64(), PG_WAIT_LOCK, PGPROC::pgxactoff, PGPROC::pid, PROC_IS_AUTOVACUUM, PROC_VACUUM_FOR_WRAPAROUND, PROC_WAIT_STATUS_ERROR, PROC_WAIT_STATUS_OK, PROC_WAIT_STATUS_WAITING, ProcGlobal, LOCALLOCK::proclock, LOCK::procLocks, PROCSIG_RECOVERY_CONFLICT_LOCK, RecoveryInProgress(), RememberSimpleDeadLock(), RemoveFromWaitQueue(), ResetLatch(), ResolveRecoveryConflictWithLock(), SHMQueueInsertBefore(), SHMQueueNext(), PROC_QUEUE::size, PROC_HDR::statusFlags, LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, TimestampDifference(), TimestampDifferenceExceeds(), TMPARAM_AFTER, EnableTimeoutParams::type, WaitLatch(), PGPROC::waitLock, PGPROC::waitLockMode, LOCK::waitMask, PGPROC::waitProcLock, LOCK::waitProcs, PGPROC::waitStart, PGPROC::waitStatus, WARNING, WL_EXIT_ON_PM_DEATH, and WL_LATCH_SET.

Referenced by WaitOnLock().

◆ ProcWaitForSignal()

void ProcWaitForSignal ( uint32  wait_event_info)

◆ ProcWakeup()

PGPROC* ProcWakeup ( PGPROC proc,
ProcWaitStatus  waitStatus 
)

Definition at line 1665 of file proc.c.

1666 {
1667  PGPROC *retProc;
1668 
1669  /* Proc should be sleeping ... */
1670  if (proc->links.prev == NULL ||
1671  proc->links.next == NULL)
1672  return NULL;
1674 
1675  /* Save next process before we zap the list link */
1676  retProc = (PGPROC *) proc->links.next;
1677 
1678  /* Remove process from wait queue */
1679  SHMQueueDelete(&(proc->links));
1680  (proc->waitLock->waitProcs.size)--;
1681 
1682  /* Clean up process' state and pass it the ok/fail signal */
1683  proc->waitLock = NULL;
1684  proc->waitProcLock = NULL;
1685  proc->waitStatus = waitStatus;
1687 
1688  /* And awaken it */
1689  SetLatch(&proc->procLatch);
1690 
1691  return retProc;
1692 }
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68

References Assert(), PGPROC::links, MyProc, SHM_QUEUE::next, pg_atomic_write_u64(), SHM_QUEUE::prev, PROC_WAIT_STATUS_WAITING, PGPROC::procLatch, SetLatch(), SHMQueueDelete(), PROC_QUEUE::size, PGPROC::waitLock, PGPROC::waitProcLock, LOCK::waitProcs, PGPROC::waitStart, and PGPROC::waitStatus.

Referenced by ProcLockWakeup().

◆ RemoveProcFromArray()

static void RemoveProcFromArray ( int  code,
Datum  arg 
)
static

Definition at line 792 of file proc.c.

793 {
794  Assert(MyProc != NULL);
796 }
void ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
Definition: procarray.c:556

References Assert(), InvalidTransactionId, MyProc, and ProcArrayRemove().

Referenced by InitProcessPhase2().

◆ SetStartupBufferPinWaitBufId()

void SetStartupBufferPinWaitBufId ( int  bufid)

Definition at line 633 of file proc.c.

634 {
635  /* use volatile pointer to prevent code rearrangement */
636  volatile PROC_HDR *procglobal = ProcGlobal;
637 
638  procglobal->startupBufferPinWaitBufId = bufid;
639 }

References ProcGlobal, and PROC_HDR::startupBufferPinWaitBufId.

Referenced by LockBufferForCleanup().

Variable Documentation

◆ AuxiliaryProcs

NON_EXEC_STATIC PGPROC* AuxiliaryProcs = NULL

◆ deadlock_state

DeadLockState deadlock_state = DS_NOT_YET_CHECKED
static

Definition at line 87 of file proc.c.

Referenced by CheckDeadLock(), and ProcSleep().

◆ DeadlockTimeout

◆ got_deadlock_timeout

volatile sig_atomic_t got_deadlock_timeout
static

Definition at line 90 of file proc.c.

Referenced by CheckDeadLockAlert(), and ProcSleep().

◆ IdleInTransactionSessionTimeout

int IdleInTransactionSessionTimeout = 0

Definition at line 63 of file proc.c.

Referenced by PostgresMain(), and ProcessInterrupts().

◆ IdleSessionTimeout

int IdleSessionTimeout = 0

Definition at line 64 of file proc.c.

Referenced by PostgresMain(), and ProcessInterrupts().

◆ lockAwaited

LOCALLOCK* lockAwaited = NULL
static

Definition at line 85 of file proc.c.

Referenced by IsWaitingForLock(), LockErrorCleanup(), and ProcSleep().

◆ LockTimeout

int LockTimeout = 0

Definition at line 62 of file proc.c.

Referenced by ProcSleep().

◆ log_lock_waits

bool log_lock_waits = false

Definition at line 65 of file proc.c.

Referenced by ProcSleep().

◆ MyProc

PGPROC* MyProc = NULL

Definition at line 68 of file proc.c.

Referenced by _bt_parallel_build_main(), AbortTransaction(), AtEOSubXact_Namespace(), AtEOXact_Namespace(), AtEOXact_Snapshot(), attach_to_queues(), AutoVacWorkerMain(), AuxiliaryProcKill(), BackgroundWriterMain(), BaseInit(), BecomeLockGroupLeader(), BecomeLockGroupMember(), CheckDeadLock(), CheckpointerMain(), CommitTransaction(), ComputeXidHorizons(), ConditionVariableBroadcast(), ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableTimedSleep(), CountOtherDBBackends(), CreateReplicationSlot(), DefineIndex(), EndPrepare(), errdetail_abort(), exec_eval_simple_expr(), exec_simple_check_plan(), exec_stmt_call(), ExecParallelGetReceiver(), ExecParallelSetupTupleQueues(), ExportSnapshot(), FastPathGetRelationLockEntry(), FastPathGrantRelationLock(), FastPathUnGrantRelationLock(), FindLockCycleRecurseMember(), fmgr_sql(), get_cast_hashentry(), GetCurrentVirtualXIDs(), GetLockConflicts(), GetNewTransactionId(), GetSerializableTransactionSnapshotInt(), GetSnapshotData(), GetSnapshotDataReuse(), GetStableLatestTransactionId(), init_sql_fcache(), InitAuxiliaryProcess(), InitBufferPoolAccess(), InitializeParallelDSM(), InitializeSessionUserId(), InitPostgres(), InitProcess(), InitProcessPhase2(), InitTempTableNamespace(), InitWalSenderSlot(), lock_and_open_sequence(), LockAcquireExtended(), LockBufferForCleanup(), LockCheckConflicts(), LockErrorCleanup(), LockRelease(), LockReleaseAll(), log_line_prefix(), logicalrep_worker_attach(), LWLockAcquire(), LWLockAcquireOrWait(), LWLockAttemptLock(), LWLockDequeueSelf(), LWLockQueueSelf(), LWLockWaitForVar(), MarkAsPreparingGuts(), MarkBufferDirtyHint(), MinimumActiveBackends(), parallel_vacuum_main(), ParallelWorkerMain(), PgArchiverMain(), pgstat_report_activity(), PhysicalReplicationSlotNewXmin(), PostPrepare_Locks(), PrepareTransaction(), ProcArrayGroupClearXid(), ProcArrayInstallImportedXmin(), ProcArrayInstallRestoredXmin(), ProcessStandbyHSFeedbackMessage(), ProcKill(), ProcReleaseLocks(), ProcSleep(), ProcWakeup(), RecordTransactionCommit(), RecordTransactionCommitPrepared(), RecoveryConflictInterrupt(), ReinitializeParallelDSM(), RelationTruncate(), RemoveProcFromArray(), ReplicationSlotRelease(), ResolveRecoveryConflictWithLock(), set_indexsafe_procflags(), setup_dynamic_shared_memory(), SharedInvalBackendInit(), shm_mq_attach(), shm_mq_detach_internal(), shm_mq_receive(), shm_mq_sendv(), shm_mq_wait_for_attach(), SnapBuildInitialSnapshot(), SnapshotResetXmin(), StartTransaction(), StartupDecodingContext(), SwitchBackToLocalLatch(), SwitchToSharedLatch(), SyncRepCancelWait(), SyncRepCleanupAtProcExit(), SyncRepQueueInsert(), SyncRepWaitForLSN(), TerminateOtherDBBackends(), TransactionGroupUpdateXidStatus(), TransactionIdIsInProgress(), TransactionIdLimitedForOldSnapshots(), TransactionIdSetPageStatus(), TruncateMultiXact(), UnlockBuffers(), vacuum_rel(), VirtualXactLockTableCleanup(), VirtualXactLockTableInsert(), WaitXLogInsertionsToFinish(), WALInsertLockAcquire(), WalReceiverMain(), WalWriterMain(), write_csvlog(), write_jsonlog(), XidCacheRemoveRunningXids(), and XLogSaveBufferForHint().

◆ PreparedXactProcs

PGPROC* PreparedXactProcs = NULL

Definition at line 82 of file proc.c.

Referenced by InitProcGlobal(), and TwoPhaseShmemInit().

◆ ProcGlobal

◆ ProcStructLock

NON_EXEC_STATIC slock_t* ProcStructLock = NULL

◆ StatementTimeout

int StatementTimeout = 0

Definition at line 61 of file proc.c.

Referenced by enable_statement_timeout().