PostgreSQL Source Code  git master
lock.h File Reference
#include "storage/lockdefs.h"
#include "storage/backendid.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
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Data Structures

struct  PROC_QUEUE
 
struct  VirtualTransactionId
 
struct  LockMethodData
 
struct  LOCKTAG
 
struct  LOCK
 
struct  PROCLOCKTAG
 
struct  PROCLOCK
 
struct  LOCALLOCKTAG
 
struct  LOCALLOCKOWNER
 
struct  LOCALLOCK
 
struct  LockInstanceData
 
struct  LockData
 
struct  BlockedProcData
 
struct  BlockedProcsData
 

Macros

#define InvalidLocalTransactionId   0
 
#define LocalTransactionIdIsValid(lxid)   ((lxid) != InvalidLocalTransactionId)
 
#define VirtualTransactionIdIsValid(vxid)
 
#define VirtualTransactionIdEquals(vxid1, vxid2)
 
#define SetInvalidVirtualTransactionId(vxid)
 
#define GET_VXID_FROM_PGPROC(vxid, proc)
 
#define MAX_LOCKMODES   10
 
#define LOCKBIT_ON(lockmode)   (1 << (lockmode))
 
#define LOCKBIT_OFF(lockmode)   (~(1 << (lockmode)))
 
#define DEFAULT_LOCKMETHOD   1
 
#define USER_LOCKMETHOD   2
 
#define LOCKTAG_LAST_TYPE   LOCKTAG_ADVISORY
 
#define SET_LOCKTAG_RELATION(locktag, dboid, reloid)
 
#define SET_LOCKTAG_RELATION_EXTEND(locktag, dboid, reloid)
 
#define SET_LOCKTAG_PAGE(locktag, dboid, reloid, blocknum)
 
#define SET_LOCKTAG_TUPLE(locktag, dboid, reloid, blocknum, offnum)
 
#define SET_LOCKTAG_TRANSACTION(locktag, xid)
 
#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid)
 
#define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag, xid, token)
 
#define SET_LOCKTAG_OBJECT(locktag, dboid, classoid, objoid, objsubid)
 
#define SET_LOCKTAG_ADVISORY(locktag, id1, id2, id3, id4)
 
#define LOCK_LOCKMETHOD(lock)   ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)
 
#define PROCLOCK_LOCKMETHOD(proclock)   LOCK_LOCKMETHOD(*((proclock).tag.myLock))
 
#define LOCALLOCK_LOCKMETHOD(llock)   ((llock).tag.lock.locktag_lockmethodid)
 
#define LockHashPartition(hashcode)   ((hashcode) % NUM_LOCK_PARTITIONS)
 
#define LockHashPartitionLock(hashcode)
 
#define LockHashPartitionLockByIndex(i)   (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock)
 
#define LockHashPartitionLockByProc(leader_pgproc)   LockHashPartitionLock((leader_pgproc)->pgprocno)
 

Typedefs

typedef struct PGPROC PGPROC
 
typedef struct PROC_QUEUE PROC_QUEUE
 
typedef struct LockMethodData LockMethodData
 
typedef const LockMethodDataLockMethod
 
typedef uint16 LOCKMETHODID
 
typedef enum LockTagType LockTagType
 
typedef struct LOCKTAG LOCKTAG
 
typedef struct LOCK LOCK
 
typedef struct PROCLOCKTAG PROCLOCKTAG
 
typedef struct PROCLOCK PROCLOCK
 
typedef struct LOCALLOCKTAG LOCALLOCKTAG
 
typedef struct LOCALLOCKOWNER LOCALLOCKOWNER
 
typedef struct LOCALLOCK LOCALLOCK
 
typedef struct LockInstanceData LockInstanceData
 
typedef struct LockData LockData
 
typedef struct BlockedProcData BlockedProcData
 
typedef struct BlockedProcsData BlockedProcsData
 

Enumerations

enum  LockTagType {
  LOCKTAG_RELATION, LOCKTAG_RELATION_EXTEND, LOCKTAG_PAGE, LOCKTAG_TUPLE,
  LOCKTAG_TRANSACTION, LOCKTAG_VIRTUALTRANSACTION, LOCKTAG_SPECULATIVE_TOKEN, LOCKTAG_OBJECT,
  LOCKTAG_USERLOCK, LOCKTAG_ADVISORY
}
 
enum  LockAcquireResult { LOCKACQUIRE_NOT_AVAIL, LOCKACQUIRE_OK, LOCKACQUIRE_ALREADY_HELD, LOCKACQUIRE_ALREADY_CLEAR }
 
enum  DeadLockState {
  DS_NOT_YET_CHECKED, DS_NO_DEADLOCK, DS_SOFT_DEADLOCK, DS_HARD_DEADLOCK,
  DS_BLOCKED_BY_AUTOVACUUM
}
 

Functions

void InitLocks (void)
 
LockMethod GetLocksMethodTable (const LOCK *lock)
 
LockMethod GetLockTagsMethodTable (const LOCKTAG *locktag)
 
uint32 LockTagHashCode (const LOCKTAG *locktag)
 
bool DoLockModesConflict (LOCKMODE mode1, LOCKMODE mode2)
 
LockAcquireResult LockAcquire (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait)
 
LockAcquireResult LockAcquireExtended (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait, bool reportMemoryError, LOCALLOCK **locallockp)
 
void AbortStrongLockAcquire (void)
 
void MarkLockClear (LOCALLOCK *locallock)
 
bool LockRelease (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
 
void LockReleaseAll (LOCKMETHODID lockmethodid, bool allLocks)
 
void LockReleaseSession (LOCKMETHODID lockmethodid)
 
void LockReleaseCurrentOwner (LOCALLOCK **locallocks, int nlocks)
 
void LockReassignCurrentOwner (LOCALLOCK **locallocks, int nlocks)
 
bool LockHeldByMe (const LOCKTAG *locktag, LOCKMODE lockmode)
 
bool LockHasWaiters (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
 
VirtualTransactionIdGetLockConflicts (const LOCKTAG *locktag, LOCKMODE lockmode, int *countp)
 
void AtPrepare_Locks (void)
 
void PostPrepare_Locks (TransactionId xid)
 
int LockCheckConflicts (LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
 
void GrantLock (LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
 
void GrantAwaitedLock (void)
 
void RemoveFromWaitQueue (PGPROC *proc, uint32 hashcode)
 
Size LockShmemSize (void)
 
LockDataGetLockStatusData (void)
 
BlockedProcsDataGetBlockerStatusData (int blocked_pid)
 
xl_standby_lockGetRunningTransactionLocks (int *nlocks)
 
const char * GetLockmodeName (LOCKMETHODID lockmethodid, LOCKMODE mode)
 
void lock_twophase_recover (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void lock_twophase_postcommit (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void lock_twophase_postabort (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
void lock_twophase_standby_recover (TransactionId xid, uint16 info, void *recdata, uint32 len)
 
DeadLockState DeadLockCheck (PGPROC *proc)
 
PGPROCGetBlockingAutoVacuumPgproc (void)
 
void DeadLockReport (void) pg_attribute_noreturn()
 
void RememberSimpleDeadLock (PGPROC *proc1, LOCKMODE lockmode, LOCK *lock, PGPROC *proc2)
 
void InitDeadLockChecking (void)
 
int LockWaiterCount (const LOCKTAG *locktag)
 
void VirtualXactLockTableInsert (VirtualTransactionId vxid)
 
void VirtualXactLockTableCleanup (void)
 
bool VirtualXactLock (VirtualTransactionId vxid, bool wait)
 

Variables

int max_locks_per_xact
 
const char *const LockTagTypeNames []
 

Macro Definition Documentation

◆ DEFAULT_LOCKMETHOD

#define DEFAULT_LOCKMETHOD   1

◆ GET_VXID_FROM_PGPROC

#define GET_VXID_FROM_PGPROC (   vxid,
  proc 
)
Value:
((vxid).backendId = (proc).backendId, \
(vxid).localTransactionId = (proc).lxid)

Definition at line 80 of file lock.h.

Referenced by CancelDBBackends(), CancelVirtualTransaction(), GetConflictingVirtualXIDs(), GetCurrentVirtualXIDs(), GetLockConflicts(), GetSerializableTransactionSnapshotInt(), GetVirtualXIDsDelayingChkpt(), and HaveVirtualXIDsDelayingChkpt().

◆ InvalidLocalTransactionId

◆ LOCALLOCK_LOCKMETHOD

#define LOCALLOCK_LOCKMETHOD (   llock)    ((llock).tag.lock.locktag_lockmethodid)

Definition at line 422 of file lock.h.

Referenced by LockReleaseAll(), LockReleaseSession(), and WaitOnLock().

◆ LocalTransactionIdIsValid

#define LocalTransactionIdIsValid (   lxid)    ((lxid) != InvalidLocalTransactionId)

Definition at line 70 of file lock.h.

Referenced by GetNextLocalTransactionId(), and VirtualXactLockTableCleanup().

◆ LOCK_LOCKMETHOD

#define LOCK_LOCKMETHOD (   lock)    ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)

Definition at line 304 of file lock.h.

Referenced by GetLocksMethodTable(), LockReleaseAll(), and RemoveFromWaitQueue().

◆ LOCKBIT_OFF

#define LOCKBIT_OFF (   lockmode)    (~(1 << (lockmode)))

Definition at line 88 of file lock.h.

Referenced by GrantLock(), pg_lock_status(), RemoveFromWaitQueue(), and UnGrantLock().

◆ LOCKBIT_ON

◆ LockHashPartition

#define LockHashPartition (   hashcode)    ((hashcode) % NUM_LOCK_PARTITIONS)

Definition at line 501 of file lock.h.

Referenced by lock_twophase_recover(), and SetupLockInTable().

◆ LockHashPartitionLock

#define LockHashPartitionLock (   hashcode)

◆ LockHashPartitionLockByIndex

#define LockHashPartitionLockByIndex (   i)    (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock)

◆ LockHashPartitionLockByProc

#define LockHashPartitionLockByProc (   leader_pgproc)    LockHashPartitionLock((leader_pgproc)->pgprocno)

Definition at line 518 of file lock.h.

Referenced by BecomeLockGroupLeader(), BecomeLockGroupMember(), and ProcKill().

◆ LOCKTAG_LAST_TYPE

#define LOCKTAG_LAST_TYPE   LOCKTAG_ADVISORY

Definition at line 152 of file lock.h.

Referenced by GetLockNameFromTagType(), and pg_lock_status().

◆ MAX_LOCKMODES

◆ PROCLOCK_LOCKMETHOD

#define PROCLOCK_LOCKMETHOD (   proclock)    LOCK_LOCKMETHOD(*((proclock).tag.myLock))

Definition at line 361 of file lock.h.

◆ SET_LOCKTAG_ADVISORY

#define SET_LOCKTAG_ADVISORY (   locktag,
  id1,
  id2,
  id3,
  id4 
)
Value:
((locktag).locktag_field1 = (id1), \
(locktag).locktag_field2 = (id2), \
(locktag).locktag_field3 = (id3), \
(locktag).locktag_field4 = (id4), \
(locktag).locktag_type = LOCKTAG_ADVISORY, \
(locktag).locktag_lockmethodid = USER_LOCKMETHOD)
#define USER_LOCKMETHOD
Definition: lock.h:129

Definition at line 261 of file lock.h.

◆ SET_LOCKTAG_OBJECT

#define SET_LOCKTAG_OBJECT (   locktag,
  dboid,
  classoid,
  objoid,
  objsubid 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (classoid), \
(locktag).locktag_field3 = (objoid), \
(locktag).locktag_field4 = (objsubid), \
(locktag).locktag_type = LOCKTAG_OBJECT, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128
Oid classoid
Definition: pg_shseclabel.h:31

Definition at line 253 of file lock.h.

Referenced by LockDatabaseObject(), LockSharedObject(), LockSharedObjectForSession(), UnlockDatabaseObject(), UnlockSharedObject(), and UnlockSharedObjectForSession().

◆ SET_LOCKTAG_PAGE

#define SET_LOCKTAG_PAGE (   locktag,
  dboid,
  reloid,
  blocknum 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (reloid), \
(locktag).locktag_field3 = (blocknum), \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_PAGE, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 199 of file lock.h.

Referenced by ConditionalLockPage(), LockPage(), and UnlockPage().

◆ SET_LOCKTAG_RELATION

#define SET_LOCKTAG_RELATION (   locktag,
  dboid,
  reloid 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (reloid), \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_RELATION, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 181 of file lock.h.

Referenced by CheckRelationLockedByMe(), ConditionalLockRelation(), DefineIndex(), GetLockStatusData(), index_drop(), LockHasWaitersRelation(), LockRelation(), LockRelationIdForSession(), ReindexRelationConcurrently(), SetLocktagRelationOid(), StandbyAcquireAccessExclusiveLock(), StandbyReleaseLockList(), UnlockRelation(), UnlockRelationId(), and UnlockRelationIdForSession().

◆ SET_LOCKTAG_RELATION_EXTEND

#define SET_LOCKTAG_RELATION_EXTEND (   locktag,
  dboid,
  reloid 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (reloid), \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 190 of file lock.h.

Referenced by ConditionalLockRelationForExtension(), LockRelationForExtension(), RelationExtensionLockWaiterCount(), and UnlockRelationForExtension().

◆ SET_LOCKTAG_SPECULATIVE_INSERTION

#define SET_LOCKTAG_SPECULATIVE_INSERTION (   locktag,
  xid,
  token 
)
Value:
((locktag).locktag_field1 = (xid), \
(locktag).locktag_field2 = (token), \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 238 of file lock.h.

Referenced by SpeculativeInsertionLockAcquire(), SpeculativeInsertionLockRelease(), and SpeculativeInsertionWait().

◆ SET_LOCKTAG_TRANSACTION

#define SET_LOCKTAG_TRANSACTION (   locktag,
  xid 
)
Value:
((locktag).locktag_field1 = (xid), \
(locktag).locktag_field2 = 0, \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_TRANSACTION, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 217 of file lock.h.

Referenced by ConditionalXactLockTableWait(), XactLockTableDelete(), XactLockTableInsert(), and XactLockTableWait().

◆ SET_LOCKTAG_TUPLE

#define SET_LOCKTAG_TUPLE (   locktag,
  dboid,
  reloid,
  blocknum,
  offnum 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (reloid), \
(locktag).locktag_field3 = (blocknum), \
(locktag).locktag_field4 = (offnum), \
(locktag).locktag_type = LOCKTAG_TUPLE, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 208 of file lock.h.

Referenced by ConditionalLockTuple(), LockTuple(), and UnlockTuple().

◆ SET_LOCKTAG_VIRTUALTRANSACTION

#define SET_LOCKTAG_VIRTUALTRANSACTION (   locktag,
  vxid 
)
Value:
((locktag).locktag_field1 = (vxid).backendId, \
(locktag).locktag_field2 = (vxid).localTransactionId, \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128

Definition at line 226 of file lock.h.

Referenced by GetLockStatusData(), VirtualXactLock(), and VirtualXactLockTableCleanup().

◆ SetInvalidVirtualTransactionId

#define SetInvalidVirtualTransactionId (   vxid)
Value:
((vxid).backendId = InvalidBackendId, \
(vxid).localTransactionId = InvalidLocalTransactionId)
#define InvalidBackendId
Definition: backendid.h:23
#define InvalidLocalTransactionId
Definition: lock.h:69

Definition at line 77 of file lock.h.

Referenced by InitPredicateLocks(), and WaitForOlderSnapshots().

◆ USER_LOCKMETHOD

#define USER_LOCKMETHOD   2

Definition at line 129 of file lock.h.

Referenced by DiscardAll(), pg_advisory_unlock_all(), ProcReleaseLocks(), and ShutdownPostgres().

◆ VirtualTransactionIdEquals

#define VirtualTransactionIdEquals (   vxid1,
  vxid2 
)
Value:
((vxid1).backendId == (vxid2).backendId && \
(vxid1).localTransactionId == (vxid2).localTransactionId)

Definition at line 74 of file lock.h.

Referenced by GetLockConflicts(), HaveVirtualXIDsDelayingChkpt(), and WaitForOlderSnapshots().

◆ VirtualTransactionIdIsValid

#define VirtualTransactionIdIsValid (   vxid)

Typedef Documentation

◆ BlockedProcData

◆ BlockedProcsData

◆ LOCALLOCK

◆ LOCALLOCKOWNER

◆ LOCALLOCKTAG

◆ LOCK

typedef struct LOCK LOCK

◆ LockData

◆ LockInstanceData

◆ LockMethod

Definition at line 119 of file lock.h.

◆ LockMethodData

◆ LOCKMETHODID

Definition at line 125 of file lock.h.

◆ LOCKTAG

◆ LockTagType

◆ PGPROC

Definition at line 28 of file lock.h.

◆ PROC_QUEUE

◆ PROCLOCK

◆ PROCLOCKTAG

Enumeration Type Documentation

◆ DeadLockState

Enumerator
DS_NOT_YET_CHECKED 
DS_NO_DEADLOCK 
DS_SOFT_DEADLOCK 
DS_HARD_DEADLOCK 
DS_BLOCKED_BY_AUTOVACUUM 

Definition at line 485 of file lock.h.

486 {
487  DS_NOT_YET_CHECKED, /* no deadlock check has run yet */
488  DS_NO_DEADLOCK, /* no deadlock detected */
489  DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */
490  DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */
491  DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum
492  * worker */
493 } DeadLockState;
DeadLockState
Definition: lock.h:485

◆ LockAcquireResult

Enumerator
LOCKACQUIRE_NOT_AVAIL 
LOCKACQUIRE_OK 
LOCKACQUIRE_ALREADY_HELD 
LOCKACQUIRE_ALREADY_CLEAR 

Definition at line 476 of file lock.h.

477 {
478  LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */
479  LOCKACQUIRE_OK, /* lock successfully acquired */
480  LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */
481  LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */
LockAcquireResult
Definition: lock.h:476

◆ LockTagType

Enumerator
LOCKTAG_RELATION 
LOCKTAG_RELATION_EXTEND 
LOCKTAG_PAGE 
LOCKTAG_TUPLE 
LOCKTAG_TRANSACTION 
LOCKTAG_VIRTUALTRANSACTION 
LOCKTAG_SPECULATIVE_TOKEN 
LOCKTAG_OBJECT 
LOCKTAG_USERLOCK 
LOCKTAG_ADVISORY 

Definition at line 138 of file lock.h.

139 {
140  LOCKTAG_RELATION, /* whole relation */
141  LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */
142  LOCKTAG_PAGE, /* one page of a relation */
143  LOCKTAG_TUPLE, /* one physical tuple */
144  LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
145  LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
146  LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */
147  LOCKTAG_OBJECT, /* non-relation database object */
148  LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */
149  LOCKTAG_ADVISORY /* advisory user locks */
150 } LockTagType;
LockTagType
Definition: lock.h:138

Function Documentation

◆ AbortStrongLockAcquire()

void AbortStrongLockAcquire ( void  )

Definition at line 1666 of file lock.c.

References Assert, FastPathStrongRelationLockData::count, FastPathStrongLockHashPartition, LOCALLOCK::hashcode, LOCALLOCK::holdsStrongLockCount, FastPathStrongRelationLockData::mutex, SpinLockAcquire, SpinLockRelease, and StrongLockInProgress.

Referenced by LockAcquireExtended(), and LockErrorCleanup().

1667 {
1668  uint32 fasthashcode;
1669  LOCALLOCK *locallock = StrongLockInProgress;
1670 
1671  if (locallock == NULL)
1672  return;
1673 
1674  fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
1675  Assert(locallock->holdsStrongLockCount == true);
1677  Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
1678  FastPathStrongRelationLocks->count[fasthashcode]--;
1679  locallock->holdsStrongLockCount = false;
1680  StrongLockInProgress = NULL;
1682 }
uint32 hashcode
Definition: lock.h:411
bool holdsStrongLockCount
Definition: lock.h:418
uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]
Definition: lock.c:241
#define FastPathStrongLockHashPartition(hashcode)
Definition: lock.c:235
static LOCALLOCK * StrongLockInProgress
Definition: lock.c:259
#define SpinLockAcquire(lock)
Definition: spin.h:62
static volatile FastPathStrongRelationLockData * FastPathStrongRelationLocks
Definition: lock.c:244
unsigned int uint32
Definition: c.h:358
#define SpinLockRelease(lock)
Definition: spin.h:64
#define Assert(condition)
Definition: c.h:732

◆ AtPrepare_Locks()

void AtPrepare_Locks ( void  )

Definition at line 3139 of file lock.c.

References ereport, errcode(), errmsg(), ERROR, FastPathGetRelationLockEntry(), hash_seq_init(), hash_seq_search(), LOCALLOCK::holdsStrongLockCount, i, LOCALLOCKTAG::lock, LOCALLOCK::lock, TwoPhaseLockRecord::lockmode, LOCALLOCK::lockOwners, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_type, LOCKTAG_VIRTUALTRANSACTION, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, LOCALLOCK::nLocks, LOCALLOCK::numLockOwners, LOCALLOCK::proclock, RegisterTwoPhaseRecord(), status(), PROCLOCK::tag, LOCALLOCK::tag, and TWOPHASE_RM_LOCK_ID.

Referenced by PrepareTransaction().

3140 {
3142  LOCALLOCK *locallock;
3143 
3144  /*
3145  * For the most part, we don't need to touch shared memory for this ---
3146  * all the necessary state information is in the locallock table.
3147  * Fast-path locks are an exception, however: we move any such locks to
3148  * the main table before allowing PREPARE TRANSACTION to succeed.
3149  */
3151 
3152  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3153  {
3154  TwoPhaseLockRecord record;
3155  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3156  bool haveSessionLock;
3157  bool haveXactLock;
3158  int i;
3159 
3160  /*
3161  * Ignore VXID locks. We don't want those to be held by prepared
3162  * transactions, since they aren't meaningful after a restart.
3163  */
3164  if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3165  continue;
3166 
3167  /* Ignore it if we don't actually hold the lock */
3168  if (locallock->nLocks <= 0)
3169  continue;
3170 
3171  /* Scan to see whether we hold it at session or transaction level */
3172  haveSessionLock = haveXactLock = false;
3173  for (i = locallock->numLockOwners - 1; i >= 0; i--)
3174  {
3175  if (lockOwners[i].owner == NULL)
3176  haveSessionLock = true;
3177  else
3178  haveXactLock = true;
3179  }
3180 
3181  /* Ignore it if we have only session lock */
3182  if (!haveXactLock)
3183  continue;
3184 
3185  /*
3186  * If we have both session- and transaction-level locks, fail. This
3187  * should never happen with regular locks, since we only take those at
3188  * session level in some special operations like VACUUM. It's
3189  * possible to hit this with advisory locks, though.
3190  *
3191  * It would be nice if we could keep the session hold and give away
3192  * the transactional hold to the prepared xact. However, that would
3193  * require two PROCLOCK objects, and we cannot be sure that another
3194  * PROCLOCK will be available when it comes time for PostPrepare_Locks
3195  * to do the deed. So for now, we error out while we can still do so
3196  * safely.
3197  */
3198  if (haveSessionLock)
3199  ereport(ERROR,
3200  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3201  errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3202 
3203  /*
3204  * If the local lock was taken via the fast-path, we need to move it
3205  * to the primary lock table, or just get a pointer to the existing
3206  * primary lock table entry if by chance it's already been
3207  * transferred.
3208  */
3209  if (locallock->proclock == NULL)
3210  {
3211  locallock->proclock = FastPathGetRelationLockEntry(locallock);
3212  locallock->lock = locallock->proclock->tag.myLock;
3213  }
3214 
3215  /*
3216  * Arrange to not release any strong lock count held by this lock
3217  * entry. We must retain the count until the prepared transaction is
3218  * committed or rolled back.
3219  */
3220  locallock->holdsStrongLockCount = false;
3221 
3222  /*
3223  * Create a 2PC record.
3224  */
3225  memcpy(&(record.locktag), &(locallock->tag.lock), sizeof(LOCKTAG));
3226  record.lockmode = locallock->tag.mode;
3227 
3229  &record, sizeof(TwoPhaseLockRecord));
3230  }
3231 }
PROCLOCKTAG tag
Definition: lock.h:351
LOCALLOCKTAG tag
Definition: lock.h:408
static HTAB * LockMethodLocalHash
Definition: lock.c:255
bool holdsStrongLockCount
Definition: lock.h:418
int numLockOwners
Definition: lock.h:415
LOCKTAG lock
Definition: lock.h:389
static PROCLOCK * FastPathGetRelationLockEntry(LOCALLOCK *locallock)
Definition: lock.c:2719
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
Definition: lock.h:164
int errcode(int sqlerrcode)
Definition: elog.c:570
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1204
LOCKTAG locktag
Definition: lock.c:160
#define ERROR
Definition: elog.h:43
#define ereport(elevel, rest)
Definition: elog.h:141
uint8 locktag_type
Definition: lock.h:170
#define TWOPHASE_RM_LOCK_ID
Definition: twophase_rmgr.h:25
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
LOCK * lock
Definition: lock.h:412
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
int64 nLocks
Definition: lock.h:414
int errmsg(const char *fmt,...)
Definition: elog.c:784
int i
LOCK * myLock
Definition: lock.h:344
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227
LOCKMODE lockmode
Definition: lock.c:161

◆ DeadLockCheck()

DeadLockState DeadLockCheck ( PGPROC proc)

Definition at line 217 of file deadlock.c.

References Assert, DeadLockCheckRecurse(), DS_BLOCKED_BY_AUTOVACUUM, DS_HARD_DEADLOCK, DS_NO_DEADLOCK, DS_SOFT_DEADLOCK, elog, FATAL, FindLockCycle(), GetLocksMethodTable(), i, PROC_QUEUE::links, PGPROC::links, WAIT_ORDER::lock, nCurConstraints, nPossibleConstraints, WAIT_ORDER::nProcs, nWaitOrders, ProcLockWakeup(), ProcQueueInit(), WAIT_ORDER::procs, SHMQueueInsertBefore(), PROC_QUEUE::size, and LOCK::waitProcs.

Referenced by CheckDeadLock().

218 {
219  int i,
220  j;
221 
222  /* Initialize to "no constraints" */
223  nCurConstraints = 0;
225  nWaitOrders = 0;
226 
227  /* Initialize to not blocked by an autovacuum worker */
229 
230  /* Search for deadlocks and possible fixes */
231  if (DeadLockCheckRecurse(proc))
232  {
233  /*
234  * Call FindLockCycle one more time, to record the correct
235  * deadlockDetails[] for the basic state with no rearrangements.
236  */
237  int nSoftEdges;
238 
239  TRACE_POSTGRESQL_DEADLOCK_FOUND();
240 
241  nWaitOrders = 0;
242  if (!FindLockCycle(proc, possibleConstraints, &nSoftEdges))
243  elog(FATAL, "deadlock seems to have disappeared");
244 
245  return DS_HARD_DEADLOCK; /* cannot find a non-deadlocked state */
246  }
247 
248  /* Apply any needed rearrangements of wait queues */
249  for (i = 0; i < nWaitOrders; i++)
250  {
251  LOCK *lock = waitOrders[i].lock;
252  PGPROC **procs = waitOrders[i].procs;
253  int nProcs = waitOrders[i].nProcs;
254  PROC_QUEUE *waitQueue = &(lock->waitProcs);
255 
256  Assert(nProcs == waitQueue->size);
257 
258 #ifdef DEBUG_DEADLOCK
259  PrintLockQueue(lock, "DeadLockCheck:");
260 #endif
261 
262  /* Reset the queue and re-add procs in the desired order */
263  ProcQueueInit(waitQueue);
264  for (j = 0; j < nProcs; j++)
265  {
266  SHMQueueInsertBefore(&(waitQueue->links), &(procs[j]->links));
267  waitQueue->size++;
268  }
269 
270 #ifdef DEBUG_DEADLOCK
271  PrintLockQueue(lock, "rearranged to:");
272 #endif
273 
274  /* See if any waiters for the lock can be woken up now */
275  ProcLockWakeup(GetLocksMethodTable(lock), lock);
276  }
277 
278  /* Return code tells caller if we had to escape a deadlock or not */
279  if (nWaitOrders > 0)
280  return DS_SOFT_DEADLOCK;
281  else if (blocking_autovacuum_proc != NULL)
283  else
284  return DS_NO_DEADLOCK;
285 }
static WAIT_ORDER * waitOrders
Definition: deadlock.c:111
SHM_QUEUE links
Definition: lock.h:32
SHM_QUEUE links
Definition: proc.h:98
static PGPROC * blocking_autovacuum_proc
Definition: deadlock.c:128
void SHMQueueInsertBefore(SHM_QUEUE *queue, SHM_QUEUE *elem)
Definition: shmqueue.c:89
static int nCurConstraints
Definition: deadlock.c:117
static int nPossibleConstraints
Definition: deadlock.c:122
int nProcs
Definition: deadlock.c:60
PROC_QUEUE waitProcs
Definition: lock.h:297
LOCK * lock
Definition: deadlock.c:58
static bool FindLockCycle(PGPROC *checkProc, EDGE *softEdges, int *nSoftEdges)
Definition: deadlock.c:449
PGPROC ** procs
Definition: deadlock.c:59
#define FATAL
Definition: elog.h:52
void ProcQueueInit(PROC_QUEUE *queue)
Definition: proc.c:1039
Definition: lock.h:288
void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock)
Definition: proc.c:1629
#define Assert(condition)
Definition: c.h:732
static EDGE * possibleConstraints
Definition: deadlock.c:121
static bool DeadLockCheckRecurse(PGPROC *proc)
Definition: deadlock.c:315
#define elog(elevel,...)
Definition: elog.h:226
int i
int size
Definition: lock.h:33
static int nWaitOrders
Definition: deadlock.c:112
Definition: proc.h:95
LockMethod GetLocksMethodTable(const LOCK *lock)
Definition: lock.c:460

◆ DeadLockReport()

void DeadLockReport ( void  )

Definition at line 1083 of file deadlock.c.

References _, appendBinaryStringInfo(), appendStringInfo(), appendStringInfoChar(), StringInfoData::data, DescribeLockTag(), ereport, errcode(), errdetail_internal(), errdetail_log(), errhint(), errmsg(), ERROR, GetLockmodeName(), i, initStringInfo(), StringInfoData::len, DEADLOCK_INFO::lockmode, DEADLOCK_INFO::locktag, LOCKTAG::locktag_lockmethodid, nDeadlockDetails, pgstat_get_backend_current_activity(), pgstat_report_deadlock(), DEADLOCK_INFO::pid, and resetStringInfo().

Referenced by WaitOnLock().

1084 {
1085  StringInfoData clientbuf; /* errdetail for client */
1086  StringInfoData logbuf; /* errdetail for server log */
1087  StringInfoData locktagbuf;
1088  int i;
1089 
1090  initStringInfo(&clientbuf);
1091  initStringInfo(&logbuf);
1092  initStringInfo(&locktagbuf);
1093 
1094  /* Generate the "waits for" lines sent to the client */
1095  for (i = 0; i < nDeadlockDetails; i++)
1096  {
1097  DEADLOCK_INFO *info = &deadlockDetails[i];
1098  int nextpid;
1099 
1100  /* The last proc waits for the first one... */
1101  if (i < nDeadlockDetails - 1)
1102  nextpid = info[1].pid;
1103  else
1104  nextpid = deadlockDetails[0].pid;
1105 
1106  /* reset locktagbuf to hold next object description */
1107  resetStringInfo(&locktagbuf);
1108 
1109  DescribeLockTag(&locktagbuf, &info->locktag);
1110 
1111  if (i > 0)
1112  appendStringInfoChar(&clientbuf, '\n');
1113 
1114  appendStringInfo(&clientbuf,
1115  _("Process %d waits for %s on %s; blocked by process %d."),
1116  info->pid,
1118  info->lockmode),
1119  locktagbuf.data,
1120  nextpid);
1121  }
1122 
1123  /* Duplicate all the above for the server ... */
1124  appendBinaryStringInfo(&logbuf, clientbuf.data, clientbuf.len);
1125 
1126  /* ... and add info about query strings */
1127  for (i = 0; i < nDeadlockDetails; i++)
1128  {
1129  DEADLOCK_INFO *info = &deadlockDetails[i];
1130 
1131  appendStringInfoChar(&logbuf, '\n');
1132 
1133  appendStringInfo(&logbuf,
1134  _("Process %d: %s"),
1135  info->pid,
1137  }
1138 
1140 
1141  ereport(ERROR,
1142  (errcode(ERRCODE_T_R_DEADLOCK_DETECTED),
1143  errmsg("deadlock detected"),
1144  errdetail_internal("%s", clientbuf.data),
1145  errdetail_log("%s", logbuf.data),
1146  errhint("See server log for query details.")));
1147 }
void pgstat_report_deadlock(void)
Definition: pgstat.c:1511
int errhint(const char *fmt,...)
Definition: elog.c:974
const char * GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
Definition: lock.c:3925
LOCKMODE lockmode
Definition: deadlock.c:74
int errcode(int sqlerrcode)
Definition: elog.c:570
int errdetail_internal(const char *fmt,...)
Definition: elog.c:887
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:78
#define ERROR
Definition: elog.h:43
void DescribeLockTag(StringInfo buf, const LOCKTAG *tag)
Definition: lmgr.c:1087
static int nDeadlockDetails
Definition: deadlock.c:125
void resetStringInfo(StringInfo str)
Definition: stringinfo.c:62
int errdetail_log(const char *fmt,...)
Definition: elog.c:908
#define ereport(elevel, rest)
Definition: elog.h:141
const char * pgstat_get_backend_current_activity(int pid, bool checkUser)
Definition: pgstat.c:4137
void appendStringInfoChar(StringInfo str, char ch)
Definition: stringinfo.c:175
void initStringInfo(StringInfo str)
Definition: stringinfo.c:46
static DEADLOCK_INFO * deadlockDetails
Definition: deadlock.c:124
uint8 locktag_lockmethodid
Definition: lock.h:171
int errmsg(const char *fmt,...)
Definition: elog.c:784
int i
LOCKTAG locktag
Definition: deadlock.c:73
#define _(x)
Definition: elog.c:84
void appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
Definition: stringinfo.c:214

◆ DoLockModesConflict()

bool DoLockModesConflict ( LOCKMODE  mode1,
LOCKMODE  mode2 
)

Definition at line 556 of file lock.c.

References LockMethodData::conflictTab, DEFAULT_LOCKMETHOD, and LOCKBIT_ON.

Referenced by Do_MultiXactIdWait(), DoesMultiXactIdConflict(), initialize_reloptions(), and test_lockmode_for_conflict().

557 {
558  LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
559 
560  if (lockMethodTable->conflictTab[mode1] & LOCKBIT_ON(mode2))
561  return true;
562 
563  return false;
564 }
const LOCKMASK * conflictTab
Definition: lock.h:114
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
static const LockMethod LockMethods[]
Definition: lock.c:150

◆ GetBlockerStatusData()

BlockedProcsData* GetBlockerStatusData ( int  blocked_pid)

Definition at line 3662 of file lock.c.

References Assert, BackendPidGetProcWithLock(), dlist_iter::cur, dlist_container, dlist_foreach, GetSingleProcBlockerStatusData(), i, PGPROC::lockGroupLeader, PGPROC::lockGroupMembers, LockHashPartitionLockByIndex, BlockedProcsData::locks, LW_SHARED, LWLockAcquire(), LWLockRelease(), MaxBackends, BlockedProcsData::maxlocks, BlockedProcsData::maxpids, BlockedProcsData::maxprocs, BlockedProcsData::nlocks, BlockedProcsData::npids, BlockedProcsData::nprocs, NUM_LOCK_PARTITIONS, palloc(), BlockedProcsData::procs, and BlockedProcsData::waiter_pids.

Referenced by pg_blocking_pids().

3663 {
3664  BlockedProcsData *data;
3665  PGPROC *proc;
3666  int i;
3667 
3668  data = (BlockedProcsData *) palloc(sizeof(BlockedProcsData));
3669 
3670  /*
3671  * Guess how much space we'll need, and preallocate. Most of the time
3672  * this will avoid needing to do repalloc while holding the LWLocks. (We
3673  * assume, but check with an Assert, that MaxBackends is enough entries
3674  * for the procs[] array; the other two could need enlargement, though.)
3675  */
3676  data->nprocs = data->nlocks = data->npids = 0;
3677  data->maxprocs = data->maxlocks = data->maxpids = MaxBackends;
3678  data->procs = (BlockedProcData *) palloc(sizeof(BlockedProcData) * data->maxprocs);
3679  data->locks = (LockInstanceData *) palloc(sizeof(LockInstanceData) * data->maxlocks);
3680  data->waiter_pids = (int *) palloc(sizeof(int) * data->maxpids);
3681 
3682  /*
3683  * In order to search the ProcArray for blocked_pid and assume that that
3684  * entry won't immediately disappear under us, we must hold ProcArrayLock.
3685  * In addition, to examine the lock grouping fields of any other backend,
3686  * we must hold all the hash partition locks. (Only one of those locks is
3687  * actually relevant for any one lock group, but we can't know which one
3688  * ahead of time.) It's fairly annoying to hold all those locks
3689  * throughout this, but it's no worse than GetLockStatusData(), and it
3690  * does have the advantage that we're guaranteed to return a
3691  * self-consistent instantaneous state.
3692  */
3693  LWLockAcquire(ProcArrayLock, LW_SHARED);
3694 
3695  proc = BackendPidGetProcWithLock(blocked_pid);
3696 
3697  /* Nothing to do if it's gone */
3698  if (proc != NULL)
3699  {
3700  /*
3701  * Acquire lock on the entire shared lock data structure. See notes
3702  * in GetLockStatusData().
3703  */
3704  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3706 
3707  if (proc->lockGroupLeader == NULL)
3708  {
3709  /* Easy case, proc is not a lock group member */
3710  GetSingleProcBlockerStatusData(proc, data);
3711  }
3712  else
3713  {
3714  /* Examine all procs in proc's lock group */
3715  dlist_iter iter;
3716 
3718  {
3719  PGPROC *memberProc;
3720 
3721  memberProc = dlist_container(PGPROC, lockGroupLink, iter.cur);
3722  GetSingleProcBlockerStatusData(memberProc, data);
3723  }
3724  }
3725 
3726  /*
3727  * And release locks. See notes in GetLockStatusData().
3728  */
3729  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
3731 
3732  Assert(data->nprocs <= data->maxprocs);
3733  }
3734 
3735  LWLockRelease(ProcArrayLock);
3736 
3737  return data;
3738 }
int * waiter_pids
Definition: lock.h:465
dlist_head lockGroupMembers
Definition: proc.h:204
#define dlist_foreach(iter, lhead)
Definition: ilist.h:507
BlockedProcData * procs
Definition: lock.h:463
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
PGPROC * BackendPidGetProcWithLock(int pid)
Definition: procarray.c:2386
static void GetSingleProcBlockerStatusData(PGPROC *blocked_proc, BlockedProcsData *data)
Definition: lock.c:3742
#define dlist_container(type, membername, ptr)
Definition: ilist.h:477
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:506
int MaxBackends
Definition: globals.c:135
int maxlocks
Definition: lock.h:469
LockInstanceData * locks
Definition: lock.h:464
dlist_node * cur
Definition: ilist.h:161
#define Assert(condition)
Definition: c.h:732
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
void * palloc(Size size)
Definition: mcxt.c:924
int i
Definition: proc.h:95
PGPROC * lockGroupLeader
Definition: proc.h:203
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:117
int maxprocs
Definition: lock.h:467

◆ GetBlockingAutoVacuumPgproc()

PGPROC* GetBlockingAutoVacuumPgproc ( void  )

Definition at line 293 of file deadlock.c.

References blocking_autovacuum_proc.

Referenced by ProcSleep().

294 {
295  PGPROC *ptr;
296 
299 
300  return ptr;
301 }
static PGPROC * blocking_autovacuum_proc
Definition: deadlock.c:128
Definition: proc.h:95

◆ GetLockConflicts()

VirtualTransactionId* GetLockConflicts ( const LOCKTAG locktag,
LOCKMODE  lockmode,
int *  countp 
)

Definition at line 2821 of file lock.c.

References PROC_HDR::allProcCount, PROC_HDR::allProcs, VirtualTransactionId::backendId, PGPROC::backendLock, ConflictsWithRelationFastPath, LockMethodData::conflictTab, PGPROC::databaseId, elog, ERROR, FAST_PATH_GET_BITS, FAST_PATH_LOCKNUMBER_OFFSET, FP_LOCK_SLOTS_PER_BACKEND, PGPROC::fpRelId, GET_VXID_FROM_PGPROC, HASH_FIND, hash_search_with_hash_value(), PROCLOCK::holdMask, i, InHotStandby, InvalidBackendId, InvalidLocalTransactionId, lengthof, VirtualTransactionId::localTransactionId, LockHashPartitionLock, PROCLOCK::lockLink, TwoPhaseLockRecord::lockmode, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_SHARED, LWLockAcquire(), LWLockRelease(), MaxBackends, MemoryContextAlloc(), MyProc, PROCLOCKTAG::myProc, LockMethodData::numLockModes, offsetof, palloc0(), PANIC, ProcGlobal, LOCK::procLocks, SHMQueueNext(), PROCLOCK::tag, TopMemoryContext, VirtualTransactionIdEquals, and VirtualTransactionIdIsValid.

Referenced by ResolveRecoveryConflictWithLock(), and WaitForLockersMultiple().

2822 {
2823  static VirtualTransactionId *vxids;
2824  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
2825  LockMethod lockMethodTable;
2826  LOCK *lock;
2827  LOCKMASK conflictMask;
2828  SHM_QUEUE *procLocks;
2829  PROCLOCK *proclock;
2830  uint32 hashcode;
2831  LWLock *partitionLock;
2832  int count = 0;
2833  int fast_count = 0;
2834 
2835  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2836  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2837  lockMethodTable = LockMethods[lockmethodid];
2838  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
2839  elog(ERROR, "unrecognized lock mode: %d", lockmode);
2840 
2841  /*
2842  * Allocate memory to store results, and fill with InvalidVXID. We only
2843  * need enough space for MaxBackends + a terminator, since prepared xacts
2844  * don't count. InHotStandby allocate once in TopMemoryContext.
2845  */
2846  if (InHotStandby)
2847  {
2848  if (vxids == NULL)
2849  vxids = (VirtualTransactionId *)
2851  sizeof(VirtualTransactionId) * (MaxBackends + 1));
2852  }
2853  else
2854  vxids = (VirtualTransactionId *)
2855  palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1));
2856 
2857  /* Compute hash code and partition lock, and look up conflicting modes. */
2858  hashcode = LockTagHashCode(locktag);
2859  partitionLock = LockHashPartitionLock(hashcode);
2860  conflictMask = lockMethodTable->conflictTab[lockmode];
2861 
2862  /*
2863  * Fast path locks might not have been entered in the primary lock table.
2864  * If the lock we're dealing with could conflict with such a lock, we must
2865  * examine each backend's fast-path array for conflicts.
2866  */
2867  if (ConflictsWithRelationFastPath(locktag, lockmode))
2868  {
2869  int i;
2870  Oid relid = locktag->locktag_field2;
2871  VirtualTransactionId vxid;
2872 
2873  /*
2874  * Iterate over relevant PGPROCs. Anything held by a prepared
2875  * transaction will have been transferred to the primary lock table,
2876  * so we need not worry about those. This is all a bit fuzzy, because
2877  * new locks could be taken after we've visited a particular
2878  * partition, but the callers had better be prepared to deal with that
2879  * anyway, since the locks could equally well be taken between the
2880  * time we return the value and the time the caller does something
2881  * with it.
2882  */
2883  for (i = 0; i < ProcGlobal->allProcCount; i++)
2884  {
2885  PGPROC *proc = &ProcGlobal->allProcs[i];
2886  uint32 f;
2887 
2888  /* A backend never blocks itself */
2889  if (proc == MyProc)
2890  continue;
2891 
2893 
2894  /*
2895  * If the target backend isn't referencing the same database as
2896  * the lock, then we needn't examine the individual relation IDs
2897  * at all; none of them can be relevant.
2898  *
2899  * See FastPathTransferRelationLocks() for discussion of why we do
2900  * this test after acquiring the lock.
2901  */
2902  if (proc->databaseId != locktag->locktag_field1)
2903  {
2904  LWLockRelease(&proc->backendLock);
2905  continue;
2906  }
2907 
2908  for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
2909  {
2910  uint32 lockmask;
2911 
2912  /* Look for an allocated slot matching the given relid. */
2913  if (relid != proc->fpRelId[f])
2914  continue;
2915  lockmask = FAST_PATH_GET_BITS(proc, f);
2916  if (!lockmask)
2917  continue;
2918  lockmask <<= FAST_PATH_LOCKNUMBER_OFFSET;
2919 
2920  /*
2921  * There can only be one entry per relation, so if we found it
2922  * and it doesn't conflict, we can skip the rest of the slots.
2923  */
2924  if ((lockmask & conflictMask) == 0)
2925  break;
2926 
2927  /* Conflict! */
2928  GET_VXID_FROM_PGPROC(vxid, *proc);
2929 
2930  /*
2931  * If we see an invalid VXID, then either the xact has already
2932  * committed (or aborted), or it's a prepared xact. In either
2933  * case we may ignore it.
2934  */
2935  if (VirtualTransactionIdIsValid(vxid))
2936  vxids[count++] = vxid;
2937 
2938  /* No need to examine remaining slots. */
2939  break;
2940  }
2941 
2942  LWLockRelease(&proc->backendLock);
2943  }
2944  }
2945 
2946  /* Remember how many fast-path conflicts we found. */
2947  fast_count = count;
2948 
2949  /*
2950  * Look up the lock object matching the tag.
2951  */
2952  LWLockAcquire(partitionLock, LW_SHARED);
2953 
2955  (const void *) locktag,
2956  hashcode,
2957  HASH_FIND,
2958  NULL);
2959  if (!lock)
2960  {
2961  /*
2962  * If the lock object doesn't exist, there is nothing holding a lock
2963  * on this lockable object.
2964  */
2965  LWLockRelease(partitionLock);
2966  vxids[count].backendId = InvalidBackendId;
2968  if (countp)
2969  *countp = count;
2970  return vxids;
2971  }
2972 
2973  /*
2974  * Examine each existing holder (or awaiter) of the lock.
2975  */
2976 
2977  procLocks = &(lock->procLocks);
2978 
2979  proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
2980  offsetof(PROCLOCK, lockLink));
2981 
2982  while (proclock)
2983  {
2984  if (conflictMask & proclock->holdMask)
2985  {
2986  PGPROC *proc = proclock->tag.myProc;
2987 
2988  /* A backend never blocks itself */
2989  if (proc != MyProc)
2990  {
2991  VirtualTransactionId vxid;
2992 
2993  GET_VXID_FROM_PGPROC(vxid, *proc);
2994 
2995  /*
2996  * If we see an invalid VXID, then either the xact has already
2997  * committed (or aborted), or it's a prepared xact. In either
2998  * case we may ignore it.
2999  */
3000  if (VirtualTransactionIdIsValid(vxid))
3001  {
3002  int i;
3003 
3004  /* Avoid duplicate entries. */
3005  for (i = 0; i < fast_count; ++i)
3006  if (VirtualTransactionIdEquals(vxids[i], vxid))
3007  break;
3008  if (i >= fast_count)
3009  vxids[count++] = vxid;
3010  }
3011  }
3012  }
3013 
3014  proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
3015  offsetof(PROCLOCK, lockLink));
3016  }
3017 
3018  LWLockRelease(partitionLock);
3019 
3020  if (count > MaxBackends) /* should never happen */
3021  elog(PANIC, "too many conflicting locks found");
3022 
3023  vxids[count].backendId = InvalidBackendId;
3025  if (countp)
3026  *countp = count;
3027  return vxids;
3028 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:919
PROCLOCKTAG tag
Definition: lock.h:351
Definition: lwlock.h:32
#define ConflictsWithRelationFastPath(locktag, mode)
Definition: lock.c:205
#define GET_VXID_FROM_PGPROC(vxid, proc)
Definition: lock.h:80
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
#define FAST_PATH_GET_BITS(proc, n)
Definition: lock.c:177
const LOCKMASK * conflictTab
Definition: lock.h:114
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
SHM_QUEUE lockLink
Definition: lock.h:357
#define InHotStandby
Definition: xlog.h:74
PROC_HDR * ProcGlobal
Definition: proc.c:81
#define lengthof(array)
Definition: c.h:662
unsigned int Oid
Definition: postgres_ext.h:31
LocalTransactionId localTransactionId
Definition: lock.h:66
#define PANIC
Definition: elog.h:53
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define VirtualTransactionIdEquals(vxid1, vxid2)
Definition: lock.h:74
#define ERROR
Definition: elog.h:43
int MaxBackends
Definition: globals.c:135
#define FP_LOCK_SLOTS_PER_BACKEND
Definition: proc.h:71
uint32 locktag_field2
Definition: lock.h:167
Oid databaseId
Definition: proc.h:114
unsigned int uint32
Definition: c.h:358
Definition: lock.h:288
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
MemoryContext TopMemoryContext
Definition: mcxt.c:44
uint16 LOCKMETHODID
Definition: lock.h:125
SHM_QUEUE procLocks
Definition: lock.h:296
#define VirtualTransactionIdIsValid(vxid)
Definition: lock.h:71
#define InvalidBackendId
Definition: backendid.h:23
void * palloc0(Size size)
Definition: mcxt.c:955
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
Oid fpRelId[FP_LOCK_SLOTS_PER_BACKEND]
Definition: proc.h:194
BackendId backendId
Definition: lock.h:65
LWLock backendLock
Definition: proc.h:190
static HTAB * LockMethodLockHash
Definition: lock.c:253
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
uint32 allProcCount
Definition: proc.h:251
int LOCKMASK
Definition: lockdefs.h:25
uint8 locktag_lockmethodid
Definition: lock.h:171
PGPROC * myProc
Definition: lock.h:345
#define FAST_PATH_LOCKNUMBER_OFFSET
Definition: lock.c:175
Definition: lock.h:348
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:771
#define elog(elevel,...)
Definition: elog.h:226
#define InvalidLocalTransactionId
Definition: lock.h:69
int i
PGPROC * allProcs
Definition: proc.h:247
static const LockMethod LockMethods[]
Definition: lock.c:150
uint32 locktag_field1
Definition: lock.h:166
Definition: proc.h:95
#define offsetof(type, field)
Definition: c.h:655
int numLockModes
Definition: lock.h:113

◆ GetLockmodeName()

const char* GetLockmodeName ( LOCKMETHODID  lockmethodid,
LOCKMODE  mode 
)

Definition at line 3925 of file lock.c.

References Assert, elog, hash_seq_init(), hash_seq_search(), i, lengthof, LOCK_PRINT, LockMethodData::lockModeNames, LOG, mode, PROCLOCKTAG::myLock, MyProc, PROCLOCKTAG::myProc, PGPROC::myProcLocks, NUM_LOCK_PARTITIONS, offsetof, PROCLOCK::procLink, PROCLOCK_PRINT, SHMQueueNext(), status(), PROCLOCK::tag, and PGPROC::waitLock.

Referenced by CheckRelationLockedByMe(), DeadLockReport(), pg_lock_status(), and ProcSleep().

3926 {
3927  Assert(lockmethodid > 0 && lockmethodid < lengthof(LockMethods));
3928  Assert(mode > 0 && mode <= LockMethods[lockmethodid]->numLockModes);
3929  return LockMethods[lockmethodid]->lockModeNames[mode];
3930 }
static PgChecksumMode mode
Definition: pg_checksums.c:61
#define lengthof(array)
Definition: c.h:662
#define Assert(condition)
Definition: c.h:732
static const LockMethod LockMethods[]
Definition: lock.c:150
const char *const * lockModeNames
Definition: lock.h:115

◆ GetLocksMethodTable()

LockMethod GetLocksMethodTable ( const LOCK lock)

Definition at line 460 of file lock.c.

References Assert, lengthof, and LOCK_LOCKMETHOD.

Referenced by DeadLockCheck(), and FindLockCycleRecurseMember().

461 {
462  LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*lock);
463 
464  Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
465  return LockMethods[lockmethodid];
466 }
#define lengthof(array)
Definition: c.h:662
uint16 LOCKMETHODID
Definition: lock.h:125
#define Assert(condition)
Definition: c.h:732
static const LockMethod LockMethods[]
Definition: lock.c:150
#define LOCK_LOCKMETHOD(lock)
Definition: lock.h:304

◆ GetLockStatusData()

LockData* GetLockStatusData ( void  )

Definition at line 3478 of file lock.c.

References PROC_HDR::allProcCount, PROC_HDR::allProcs, Assert, LockInstanceData::backend, VirtualTransactionId::backendId, PGPROC::backendId, PGPROC::backendLock, PGPROC::databaseId, ExclusiveLock, FAST_PATH_GET_BITS, FAST_PATH_LOCKNUMBER_OFFSET, LockInstanceData::fastpath, FP_LOCK_SLOTS_PER_BACKEND, PGPROC::fpLocalTransactionId, PGPROC::fpRelId, PGPROC::fpVXIDLock, PROCLOCK::groupLeader, hash_get_num_entries(), hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, LockInstanceData::holdMask, i, LockInstanceData::leaderPid, VirtualTransactionId::localTransactionId, LOCKBIT_ON, LockHashPartitionLockByIndex, LockData::locks, LockInstanceData::locktag, LW_SHARED, LWLockAcquire(), LWLockRelease(), PGPROC::lxid, LockInstanceData::lxid, MaxBackends, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, LockData::nelements, NoLock, NUM_LOCK_PARTITIONS, palloc(), PGPROC::pid, LockInstanceData::pid, ProcGlobal, repalloc(), SET_LOCKTAG_RELATION, SET_LOCKTAG_VIRTUALTRANSACTION, LOCK::tag, PROCLOCK::tag, PGPROC::waitLock, PGPROC::waitLockMode, and LockInstanceData::waitLockMode.

Referenced by pg_lock_status().

3479 {
3480  LockData *data;
3481  PROCLOCK *proclock;
3482  HASH_SEQ_STATUS seqstat;
3483  int els;
3484  int el;
3485  int i;
3486 
3487  data = (LockData *) palloc(sizeof(LockData));
3488 
3489  /* Guess how much space we'll need. */
3490  els = MaxBackends;
3491  el = 0;
3492  data->locks = (LockInstanceData *) palloc(sizeof(LockInstanceData) * els);
3493 
3494  /*
3495  * First, we iterate through the per-backend fast-path arrays, locking
3496  * them one at a time. This might produce an inconsistent picture of the
3497  * system state, but taking all of those LWLocks at the same time seems
3498  * impractical (in particular, note MAX_SIMUL_LWLOCKS). It shouldn't
3499  * matter too much, because none of these locks can be involved in lock
3500  * conflicts anyway - anything that might must be present in the main lock
3501  * table. (For the same reason, we don't sweat about making leaderPid
3502  * completely valid. We cannot safely dereference another backend's
3503  * lockGroupLeader field without holding all lock partition locks, and
3504  * it's not worth that.)
3505  */
3506  for (i = 0; i < ProcGlobal->allProcCount; ++i)
3507  {
3508  PGPROC *proc = &ProcGlobal->allProcs[i];
3509  uint32 f;
3510 
3512 
3513  for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; ++f)
3514  {
3515  LockInstanceData *instance;
3516  uint32 lockbits = FAST_PATH_GET_BITS(proc, f);
3517 
3518  /* Skip unallocated slots. */
3519  if (!lockbits)
3520  continue;
3521 
3522  if (el >= els)
3523  {
3524  els += MaxBackends;
3525  data->locks = (LockInstanceData *)
3526  repalloc(data->locks, sizeof(LockInstanceData) * els);
3527  }
3528 
3529  instance = &data->locks[el];
3530  SET_LOCKTAG_RELATION(instance->locktag, proc->databaseId,
3531  proc->fpRelId[f]);
3532  instance->holdMask = lockbits << FAST_PATH_LOCKNUMBER_OFFSET;
3533  instance->waitLockMode = NoLock;
3534  instance->backend = proc->backendId;
3535  instance->lxid = proc->lxid;
3536  instance->pid = proc->pid;
3537  instance->leaderPid = proc->pid;
3538  instance->fastpath = true;
3539 
3540  el++;
3541  }
3542 
3543  if (proc->fpVXIDLock)
3544  {
3545  VirtualTransactionId vxid;
3546  LockInstanceData *instance;
3547 
3548  if (el >= els)
3549  {
3550  els += MaxBackends;
3551  data->locks = (LockInstanceData *)
3552  repalloc(data->locks, sizeof(LockInstanceData) * els);
3553  }
3554 
3555  vxid.backendId = proc->backendId;
3557 
3558  instance = &data->locks[el];
3559  SET_LOCKTAG_VIRTUALTRANSACTION(instance->locktag, vxid);
3560  instance->holdMask = LOCKBIT_ON(ExclusiveLock);
3561  instance->waitLockMode = NoLock;
3562  instance->backend = proc->backendId;
3563  instance->lxid = proc->lxid;
3564  instance->pid = proc->pid;
3565  instance->leaderPid = proc->pid;
3566  instance->fastpath = true;
3567 
3568  el++;
3569  }
3570 
3571  LWLockRelease(&proc->backendLock);
3572  }
3573 
3574  /*
3575  * Next, acquire lock on the entire shared lock data structure. We do
3576  * this so that, at least for locks in the primary lock table, the state
3577  * will be self-consistent.
3578  *
3579  * Since this is a read-only operation, we take shared instead of
3580  * exclusive lock. There's not a whole lot of point to this, because all
3581  * the normal operations require exclusive lock, but it doesn't hurt
3582  * anything either. It will at least allow two backends to do
3583  * GetLockStatusData in parallel.
3584  *
3585  * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
3586  */
3587  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3589 
3590  /* Now we can safely count the number of proclocks */
3592  if (data->nelements > els)
3593  {
3594  els = data->nelements;
3595  data->locks = (LockInstanceData *)
3596  repalloc(data->locks, sizeof(LockInstanceData) * els);
3597  }
3598 
3599  /* Now scan the tables to copy the data */
3601 
3602  while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
3603  {
3604  PGPROC *proc = proclock->tag.myProc;
3605  LOCK *lock = proclock->tag.myLock;
3606  LockInstanceData *instance = &data->locks[el];
3607 
3608  memcpy(&instance->locktag, &lock->tag, sizeof(LOCKTAG));
3609  instance->holdMask = proclock->holdMask;
3610  if (proc->waitLock == proclock->tag.myLock)
3611  instance->waitLockMode = proc->waitLockMode;
3612  else
3613  instance->waitLockMode = NoLock;
3614  instance->backend = proc->backendId;
3615  instance->lxid = proc->lxid;
3616  instance->pid = proc->pid;
3617  instance->leaderPid = proclock->groupLeader->pid;
3618  instance->fastpath = false;
3619 
3620  el++;
3621  }
3622 
3623  /*
3624  * And release locks. We do this in reverse order for two reasons: (1)
3625  * Anyone else who needs more than one of the locks will be trying to lock
3626  * them in increasing order; we don't want to release the other process
3627  * until it can get all the locks it needs. (2) This avoids O(N^2)
3628  * behavior inside LWLockRelease.
3629  */
3630  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
3632 
3633  Assert(el == data->nelements);
3634 
3635  return data;
3636 }
PROCLOCKTAG tag
Definition: lock.h:351
LockInstanceData * locks
Definition: lock.h:445
BackendId backendId
Definition: proc.h:113
#define ExclusiveLock
Definition: lockdefs.h:44
LOCKMASK holdMask
Definition: lock.h:355
bool fastpath
Definition: lock.h:439
LOCKMODE waitLockMode
Definition: proc.h:141
LOCKTAG tag
Definition: lock.h:291
#define FAST_PATH_GET_BITS(proc, n)
Definition: lock.c:177
Definition: lock.h:164
PROC_HDR * ProcGlobal
Definition: proc.c:81
long hash_get_num_entries(HTAB *hashp)
Definition: dynahash.c:1335
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
bool fpVXIDLock
Definition: proc.h:195
Definition: lock.h:442
LocalTransactionId localTransactionId
Definition: lock.h:66
LOCKTAG locktag
Definition: lock.h:432
LOCKMODE waitLockMode
Definition: lock.h:434
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
int leaderPid
Definition: lock.h:438
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:506
int MaxBackends
Definition: globals.c:135
#define SET_LOCKTAG_RELATION(locktag, dboid, reloid)
Definition: lock.h:181
#define NoLock
Definition: lockdefs.h:34
#define FP_LOCK_SLOTS_PER_BACKEND
Definition: proc.h:71
Oid databaseId
Definition: proc.h:114
unsigned int uint32
Definition: c.h:358
Definition: lock.h:288
LOCK * waitLock
Definition: proc.h:139
int nelements
Definition: lock.h:444
BackendId backend
Definition: lock.h:435
LocalTransactionId lxid
Definition: lock.h:436
Oid fpRelId[FP_LOCK_SLOTS_PER_BACKEND]
Definition: proc.h:194
#define Assert(condition)
Definition: c.h:732
BackendId backendId
Definition: lock.h:65
LWLock backendLock
Definition: proc.h:190
#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid)
Definition: lock.h:226
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
uint32 allProcCount
Definition: proc.h:251
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1044
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
LOCKMASK holdMask
Definition: lock.h:433
PGPROC * myProc
Definition: lock.h:345
#define FAST_PATH_LOCKNUMBER_OFFSET
Definition: lock.c:175
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
Definition: lock.h:348
void * palloc(Size size)
Definition: mcxt.c:924
int i
LOCK * myLock
Definition: lock.h:344
PGPROC * allProcs
Definition: proc.h:247
Definition: proc.h:95
int pid
Definition: proc.h:109
LocalTransactionId fpLocalTransactionId
Definition: proc.h:196
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:117
PGPROC * groupLeader
Definition: lock.h:354
LocalTransactionId lxid
Definition: proc.h:106

◆ GetLockTagsMethodTable()

LockMethod GetLockTagsMethodTable ( const LOCKTAG locktag)

Definition at line 472 of file lock.c.

References Assert, lengthof, and LOCKTAG::locktag_lockmethodid.

Referenced by pg_blocking_pids().

473 {
474  LOCKMETHODID lockmethodid = (LOCKMETHODID) locktag->locktag_lockmethodid;
475 
476  Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
477  return LockMethods[lockmethodid];
478 }
#define lengthof(array)
Definition: c.h:662
uint16 LOCKMETHODID
Definition: lock.h:125
#define Assert(condition)
Definition: c.h:732
uint8 locktag_lockmethodid
Definition: lock.h:171
static const LockMethod LockMethods[]
Definition: lock.c:150

◆ GetRunningTransactionLocks()

xl_standby_lock* GetRunningTransactionLocks ( int *  nlocks)

Definition at line 3842 of file lock.c.

References AccessExclusiveLock, PROC_HDR::allPgXact, Assert, xl_standby_lock::dbOid, hash_get_num_entries(), hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, i, LOCKBIT_ON, LockHashPartitionLockByIndex, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG_RELATION, LOCKTAG::locktag_type, LW_SHARED, LWLockAcquire(), LWLockRelease(), PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, NUM_LOCK_PARTITIONS, palloc(), PGPROC::pgprocno, ProcGlobal, xl_standby_lock::relOid, LOCK::tag, PROCLOCK::tag, TransactionIdIsValid, xl_standby_lock::xid, and PGXACT::xid.

Referenced by LogStandbySnapshot().

3843 {
3844  xl_standby_lock *accessExclusiveLocks;
3845  PROCLOCK *proclock;
3846  HASH_SEQ_STATUS seqstat;
3847  int i;
3848  int index;
3849  int els;
3850 
3851  /*
3852  * Acquire lock on the entire shared lock data structure.
3853  *
3854  * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
3855  */
3856  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3858 
3859  /* Now we can safely count the number of proclocks */
3861 
3862  /*
3863  * Allocating enough space for all locks in the lock table is overkill,
3864  * but it's more convenient and faster than having to enlarge the array.
3865  */
3866  accessExclusiveLocks = palloc(els * sizeof(xl_standby_lock));
3867 
3868  /* Now scan the tables to copy the data */
3870 
3871  /*
3872  * If lock is a currently granted AccessExclusiveLock then it will have
3873  * just one proclock holder, so locks are never accessed twice in this
3874  * particular case. Don't copy this code for use elsewhere because in the
3875  * general case this will give you duplicate locks when looking at
3876  * non-exclusive lock types.
3877  */
3878  index = 0;
3879  while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
3880  {
3881  /* make sure this definition matches the one used in LockAcquire */
3882  if ((proclock->holdMask & LOCKBIT_ON(AccessExclusiveLock)) &&
3883  proclock->tag.myLock->tag.locktag_type == LOCKTAG_RELATION)
3884  {
3885  PGPROC *proc = proclock->tag.myProc;
3886  PGXACT *pgxact = &ProcGlobal->allPgXact[proc->pgprocno];
3887  LOCK *lock = proclock->tag.myLock;
3888  TransactionId xid = pgxact->xid;
3889 
3890  /*
3891  * Don't record locks for transactions if we know they have
3892  * already issued their WAL record for commit but not yet released
3893  * lock. It is still possible that we see locks held by already
3894  * complete transactions, if they haven't yet zeroed their xids.
3895  */
3896  if (!TransactionIdIsValid(xid))
3897  continue;
3898 
3899  accessExclusiveLocks[index].xid = xid;
3900  accessExclusiveLocks[index].dbOid = lock->tag.locktag_field1;
3901  accessExclusiveLocks[index].relOid = lock->tag.locktag_field2;
3902 
3903  index++;
3904  }
3905  }
3906 
3907  Assert(index <= els);
3908 
3909  /*
3910  * And release locks. We do this in reverse order for two reasons: (1)
3911  * Anyone else who needs more than one of the locks will be trying to lock
3912  * them in increasing order; we don't want to release the other process
3913  * until it can get all the locks it needs. (2) This avoids O(N^2)
3914  * behavior inside LWLockRelease.
3915  */
3916  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
3918 
3919  *nlocks = index;
3920  return accessExclusiveLocks;
3921 }
PROCLOCKTAG tag
Definition: lock.h:351
uint32 TransactionId
Definition: c.h:507
Definition: proc.h:222
PGXACT * allPgXact
Definition: proc.h:249
LOCKMASK holdMask
Definition: lock.h:355
TransactionId xid
Definition: proc.h:224
LOCKTAG tag
Definition: lock.h:291
PROC_HDR * ProcGlobal
Definition: proc.c:81
long hash_get_num_entries(HTAB *hashp)
Definition: dynahash.c:1335
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
Definition: type.h:89
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:506
uint32 locktag_field2
Definition: lock.h:167
Definition: lock.h:288
TransactionId xid
Definition: lockdefs.h:54
uint8 locktag_type
Definition: lock.h:170
#define Assert(condition)
Definition: c.h:732
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
#define AccessExclusiveLock
Definition: lockdefs.h:45
Definition: lock.h:348
int pgprocno
Definition: proc.h:110
void * palloc(Size size)
Definition: mcxt.c:924
int i
LOCK * myLock
Definition: lock.h:344
#define TransactionIdIsValid(xid)
Definition: transam.h:41
uint32 locktag_field1
Definition: lock.h:166
Definition: proc.h:95
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:117

◆ GrantAwaitedLock()

void GrantAwaitedLock ( void  )

Definition at line 1695 of file lock.c.

References GrantLockLocal().

Referenced by LockErrorCleanup(), and ProcSleep().

1696 {
1698 }
static LOCALLOCK * awaitedLock
Definition: lock.c:260
static ResourceOwner awaitedOwner
Definition: lock.c:261
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner)
Definition: lock.c:1601

◆ GrantLock()

void GrantLock ( LOCK lock,
PROCLOCK proclock,
LOCKMODE  lockmode 
)

Definition at line 1467 of file lock.c.

References Assert, LOCK::granted, LOCK::grantMask, PROCLOCK::holdMask, LOCK_PRINT, LOCKBIT_OFF, LOCKBIT_ON, TwoPhaseLockRecord::lockmode, LOCK::nGranted, LOCK::nRequested, LOCK::requested, and LOCK::waitMask.

Referenced by FastPathGetRelationLockEntry(), FastPathTransferRelationLocks(), lock_twophase_recover(), LockAcquireExtended(), ProcLockWakeup(), ProcSleep(), and VirtualXactLock().

1468 {
1469  lock->nGranted++;
1470  lock->granted[lockmode]++;
1471  lock->grantMask |= LOCKBIT_ON(lockmode);
1472  if (lock->granted[lockmode] == lock->requested[lockmode])
1473  lock->waitMask &= LOCKBIT_OFF(lockmode);
1474  proclock->holdMask |= LOCKBIT_ON(lockmode);
1475  LOCK_PRINT("GrantLock", lock, lockmode);
1476  Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
1477  Assert(lock->nGranted <= lock->nRequested);
1478 }
int nRequested
Definition: lock.h:299
LOCKMASK holdMask
Definition: lock.h:355
int nGranted
Definition: lock.h:301
#define LOCKBIT_OFF(lockmode)
Definition: lock.h:88
int granted[MAX_LOCKMODES]
Definition: lock.h:300
LOCKMASK waitMask
Definition: lock.h:295
int requested[MAX_LOCKMODES]
Definition: lock.h:298
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
#define Assert(condition)
Definition: c.h:732
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
LOCKMASK grantMask
Definition: lock.h:294

◆ InitDeadLockChecking()

void InitDeadLockChecking ( void  )

Definition at line 143 of file deadlock.c.

References afterConstraints, beforeConstraints, MaxBackends, maxCurConstraints, maxPossibleConstraints, MemoryContextSwitchTo(), palloc(), TopMemoryContext, and visitedProcs.

Referenced by InitProcess().

144 {
145  MemoryContext oldcxt;
146 
147  /* Make sure allocations are permanent */
149 
150  /*
151  * FindLockCycle needs at most MaxBackends entries in visitedProcs[] and
152  * deadlockDetails[].
153  */
154  visitedProcs = (PGPROC **) palloc(MaxBackends * sizeof(PGPROC *));
156 
157  /*
158  * TopoSort needs to consider at most MaxBackends wait-queue entries, and
159  * it needn't run concurrently with FindLockCycle.
160  */
161  topoProcs = visitedProcs; /* re-use this space */
162  beforeConstraints = (int *) palloc(MaxBackends * sizeof(int));
163  afterConstraints = (int *) palloc(MaxBackends * sizeof(int));
164 
165  /*
166  * We need to consider rearranging at most MaxBackends/2 wait queues
167  * (since it takes at least two waiters in a queue to create a soft edge),
168  * and the expanded form of the wait queues can't involve more than
169  * MaxBackends total waiters.
170  */
171  waitOrders = (WAIT_ORDER *)
172  palloc((MaxBackends / 2) * sizeof(WAIT_ORDER));
173  waitOrderProcs = (PGPROC **) palloc(MaxBackends * sizeof(PGPROC *));
174 
175  /*
176  * Allow at most MaxBackends distinct constraints in a configuration. (Is
177  * this enough? In practice it seems it should be, but I don't quite see
178  * how to prove it. If we run out, we might fail to find a workable wait
179  * queue rearrangement even though one exists.) NOTE that this number
180  * limits the maximum recursion depth of DeadLockCheckRecurse. Making it
181  * really big might potentially allow a stack-overflow problem.
182  */
185 
186  /*
187  * Allow up to 3*MaxBackends constraints to be saved without having to
188  * re-run TestConfiguration. (This is probably more than enough, but we
189  * can survive if we run low on space by doing excess runs of
190  * TestConfiguration to re-compute constraint lists each time needed.) The
191  * last MaxBackends entries in possibleConstraints[] are reserved as
192  * output workspace for FindLockCycle.
193  */
196  (EDGE *) palloc(maxPossibleConstraints * sizeof(EDGE));
197 
198  MemoryContextSwitchTo(oldcxt);
199 }
static int maxCurConstraints
Definition: deadlock.c:118
static WAIT_ORDER * waitOrders
Definition: deadlock.c:111
Definition: deadlock.c:46
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
static PGPROC ** waitOrderProcs
Definition: deadlock.c:113
static PGPROC ** topoProcs
Definition: deadlock.c:106
int MaxBackends
Definition: globals.c:135
static EDGE * curConstraints
Definition: deadlock.c:116
MemoryContext TopMemoryContext
Definition: mcxt.c:44
static int * afterConstraints
Definition: deadlock.c:108
static DEADLOCK_INFO * deadlockDetails
Definition: deadlock.c:124
static PGPROC ** visitedProcs
Definition: deadlock.c:102
static EDGE * possibleConstraints
Definition: deadlock.c:121
void * palloc(Size size)
Definition: mcxt.c:924
static int maxPossibleConstraints
Definition: deadlock.c:123
static int * beforeConstraints
Definition: deadlock.c:107
Definition: proc.h:95

◆ InitLocks()

void InitLocks ( void  )

Definition at line 377 of file lock.c.

References HASHCTL::entrysize, HASHCTL::hash, HASH_BLOBS, hash_create(), hash_destroy(), HASH_ELEM, HASH_FUNCTION, HASH_PARTITION, HASHCTL::keysize, MemSet, FastPathStrongRelationLockData::mutex, NLOCKENTS, NUM_LOCK_PARTITIONS, HASHCTL::num_partitions, proclock_hash(), ShmemInitHash(), ShmemInitStruct(), and SpinLockInit.

Referenced by CreateSharedMemoryAndSemaphores().

378 {
379  HASHCTL info;
380  long init_table_size,
381  max_table_size;
382  bool found;
383 
384  /*
385  * Compute init/max size to request for lock hashtables. Note these
386  * calculations must agree with LockShmemSize!
387  */
388  max_table_size = NLOCKENTS();
389  init_table_size = max_table_size / 2;
390 
391  /*
392  * Allocate hash table for LOCK structs. This stores per-locked-object
393  * information.
394  */
395  MemSet(&info, 0, sizeof(info));
396  info.keysize = sizeof(LOCKTAG);
397  info.entrysize = sizeof(LOCK);
399 
400  LockMethodLockHash = ShmemInitHash("LOCK hash",
401  init_table_size,
402  max_table_size,
403  &info,
405 
406  /* Assume an average of 2 holders per lock */
407  max_table_size *= 2;
408  init_table_size *= 2;
409 
410  /*
411  * Allocate hash table for PROCLOCK structs. This stores
412  * per-lock-per-holder information.
413  */
414  info.keysize = sizeof(PROCLOCKTAG);
415  info.entrysize = sizeof(PROCLOCK);
416  info.hash = proclock_hash;
418 
419  LockMethodProcLockHash = ShmemInitHash("PROCLOCK hash",
420  init_table_size,
421  max_table_size,
422  &info,
424 
425  /*
426  * Allocate fast-path structures.
427  */
429  ShmemInitStruct("Fast Path Strong Relation Lock Data",
430  sizeof(FastPathStrongRelationLockData), &found);
431  if (!found)
433 
434  /*
435  * Allocate non-shared hash table for LOCALLOCK structs. This stores lock
436  * counts and resource owner information.
437  *
438  * The non-shared table could already exist in this process (this occurs
439  * when the postmaster is recreating shared memory after a backend crash).
440  * If so, delete and recreate it. (We could simply leave it, since it
441  * ought to be empty in the postmaster, but for safety let's zap it.)
442  */
445 
446  info.keysize = sizeof(LOCALLOCKTAG);
447  info.entrysize = sizeof(LOCALLOCK);
448 
449  LockMethodLocalHash = hash_create("LOCALLOCK hash",
450  16,
451  &info,
453 }
void hash_destroy(HTAB *hashp)
Definition: dynahash.c:814
static HTAB * LockMethodLocalHash
Definition: lock.c:255
#define HASH_ELEM
Definition: hsearch.h:87
#define SpinLockInit(lock)
Definition: spin.h:60
Size entrysize
Definition: hsearch.h:73
static uint32 proclock_hash(const void *key, Size keysize)
Definition: lock.c:507
#define MemSet(start, val, len)
Definition: c.h:955
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
struct LOCALLOCKTAG LOCALLOCKTAG
#define HASH_PARTITION
Definition: hsearch.h:83
#define NLOCKENTS()
Definition: lock.c:56
struct LOCALLOCK LOCALLOCK
static volatile FastPathStrongRelationLockData * FastPathStrongRelationLocks
Definition: lock.c:244
long num_partitions
Definition: hsearch.h:67
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:372
struct PROCLOCK PROCLOCK
struct LOCKTAG LOCKTAG
#define HASH_BLOBS
Definition: hsearch.h:88
struct PROCLOCKTAG PROCLOCKTAG
HTAB * hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
Definition: dynahash.c:316
Size keysize
Definition: hsearch.h:72
struct LOCK LOCK
static HTAB * LockMethodLockHash
Definition: lock.c:253
HTAB * ShmemInitHash(const char *name, long init_size, long max_size, HASHCTL *infoP, int hash_flags)
Definition: shmem.c:317
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:117
HashValueFunc hash
Definition: hsearch.h:74
#define HASH_FUNCTION
Definition: hsearch.h:89

◆ lock_twophase_postabort()

void lock_twophase_postabort ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 4277 of file lock.c.

References lock_twophase_postcommit().

4279 {
4280  lock_twophase_postcommit(xid, info, recdata, len);
4281 }
void lock_twophase_postcommit(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4251

◆ lock_twophase_postcommit()

void lock_twophase_postcommit ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 4251 of file lock.c.

References Assert, elog, ERROR, lengthof, TwoPhaseLockRecord::lockmode, LockRefindAndRelease(), TwoPhaseLockRecord::locktag, LOCKTAG::locktag_lockmethodid, and TwoPhaseGetDummyProc().

Referenced by lock_twophase_postabort().

4253 {
4254  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4255  PGPROC *proc = TwoPhaseGetDummyProc(xid, true);
4256  LOCKTAG *locktag;
4257  LOCKMETHODID lockmethodid;
4258  LockMethod lockMethodTable;
4259 
4260  Assert(len == sizeof(TwoPhaseLockRecord));
4261  locktag = &rec->locktag;
4262  lockmethodid = locktag->locktag_lockmethodid;
4263 
4264  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4265  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4266  lockMethodTable = LockMethods[lockmethodid];
4267 
4268  LockRefindAndRelease(lockMethodTable, proc, locktag, rec->lockmode, true);
4269 }
static void LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, LOCKTAG *locktag, LOCKMODE lockmode, bool decrement_strong_lock_count)
Definition: lock.c:3042
Definition: lock.h:164
#define lengthof(array)
Definition: c.h:662
LOCKTAG locktag
Definition: lock.c:160
#define ERROR
Definition: elog.h:43
PGPROC * TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
Definition: twophase.c:879
uint16 LOCKMETHODID
Definition: lock.h:125
#define Assert(condition)
Definition: c.h:732
uint8 locktag_lockmethodid
Definition: lock.h:171
#define elog(elevel,...)
Definition: elog.h:226
static const LockMethod LockMethods[]
Definition: lock.c:150
LOCKMODE lockmode
Definition: lock.c:161
Definition: proc.h:95

◆ lock_twophase_recover()

void lock_twophase_recover ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 4038 of file lock.c.

References Assert, ConflictsWithRelationFastPath, FastPathStrongRelationLockData::count, elog, ereport, errcode(), errhint(), errmsg(), ERROR, FastPathStrongLockHashPartition, LOCK::granted, GrantLock(), LOCK::grantMask, PROCLOCK::groupLeader, HASH_ENTER_NULL, HASH_REMOVE, hash_search_with_hash_value(), PROCLOCK::holdMask, lengthof, LOCK_PRINT, LOCKBIT_ON, PGPROC::lockGroupLeader, LockHashPartition, LockHashPartitionLock, PROCLOCK::lockLink, TwoPhaseLockRecord::lockmode, LockMethodData::lockModeNames, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAX_LOCKMODES, MemSet, FastPathStrongRelationLockData::mutex, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, PGPROC::myProcLocks, LOCK::nGranted, LOCK::nRequested, PANIC, PROCLOCK::procLink, PROCLOCK_PRINT, ProcLockHashCode(), LOCK::procLocks, ProcQueueInit(), PROCLOCK::releaseMask, LOCK::requested, SHMQueueEmpty(), SHMQueueInit(), SHMQueueInsertBefore(), SpinLockAcquire, SpinLockRelease, LOCK::tag, TwoPhaseGetDummyProc(), LOCK::waitMask, and LOCK::waitProcs.

4040 {
4041  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4042  PGPROC *proc = TwoPhaseGetDummyProc(xid, false);
4043  LOCKTAG *locktag;
4044  LOCKMODE lockmode;
4045  LOCKMETHODID lockmethodid;
4046  LOCK *lock;
4047  PROCLOCK *proclock;
4048  PROCLOCKTAG proclocktag;
4049  bool found;
4050  uint32 hashcode;
4051  uint32 proclock_hashcode;
4052  int partition;
4053  LWLock *partitionLock;
4054  LockMethod lockMethodTable;
4055 
4056  Assert(len == sizeof(TwoPhaseLockRecord));
4057  locktag = &rec->locktag;
4058  lockmode = rec->lockmode;
4059  lockmethodid = locktag->locktag_lockmethodid;
4060 
4061  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4062  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4063  lockMethodTable = LockMethods[lockmethodid];
4064 
4065  hashcode = LockTagHashCode(locktag);
4066  partition = LockHashPartition(hashcode);
4067  partitionLock = LockHashPartitionLock(hashcode);
4068 
4069  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4070 
4071  /*
4072  * Find or create a lock with this tag.
4073  */
4075  (void *) locktag,
4076  hashcode,
4078  &found);
4079  if (!lock)
4080  {
4081  LWLockRelease(partitionLock);
4082  ereport(ERROR,
4083  (errcode(ERRCODE_OUT_OF_MEMORY),
4084  errmsg("out of shared memory"),
4085  errhint("You might need to increase max_locks_per_transaction.")));
4086  }
4087 
4088  /*
4089  * if it's a new lock object, initialize it
4090  */
4091  if (!found)
4092  {
4093  lock->grantMask = 0;
4094  lock->waitMask = 0;
4095  SHMQueueInit(&(lock->procLocks));
4096  ProcQueueInit(&(lock->waitProcs));
4097  lock->nRequested = 0;
4098  lock->nGranted = 0;
4099  MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
4100  MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
4101  LOCK_PRINT("lock_twophase_recover: new", lock, lockmode);
4102  }
4103  else
4104  {
4105  LOCK_PRINT("lock_twophase_recover: found", lock, lockmode);
4106  Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
4107  Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
4108  Assert(lock->nGranted <= lock->nRequested);
4109  }
4110 
4111  /*
4112  * Create the hash key for the proclock table.
4113  */
4114  proclocktag.myLock = lock;
4115  proclocktag.myProc = proc;
4116 
4117  proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
4118 
4119  /*
4120  * Find or create a proclock entry with this tag
4121  */
4123  (void *) &proclocktag,
4124  proclock_hashcode,
4126  &found);
4127  if (!proclock)
4128  {
4129  /* Oops, not enough shmem for the proclock */
4130  if (lock->nRequested == 0)
4131  {
4132  /*
4133  * There are no other requestors of this lock, so garbage-collect
4134  * the lock object. We *must* do this to avoid a permanent leak
4135  * of shared memory, because there won't be anything to cause
4136  * anyone to release the lock object later.
4137  */
4138  Assert(SHMQueueEmpty(&(lock->procLocks)));
4140  (void *) &(lock->tag),
4141  hashcode,
4142  HASH_REMOVE,
4143  NULL))
4144  elog(PANIC, "lock table corrupted");
4145  }
4146  LWLockRelease(partitionLock);
4147  ereport(ERROR,
4148  (errcode(ERRCODE_OUT_OF_MEMORY),
4149  errmsg("out of shared memory"),
4150  errhint("You might need to increase max_locks_per_transaction.")));
4151  }
4152 
4153  /*
4154  * If new, initialize the new entry
4155  */
4156  if (!found)
4157  {
4158  Assert(proc->lockGroupLeader == NULL);
4159  proclock->groupLeader = proc;
4160  proclock->holdMask = 0;
4161  proclock->releaseMask = 0;
4162  /* Add proclock to appropriate lists */
4163  SHMQueueInsertBefore(&lock->procLocks, &proclock->lockLink);
4164  SHMQueueInsertBefore(&(proc->myProcLocks[partition]),
4165  &proclock->procLink);
4166  PROCLOCK_PRINT("lock_twophase_recover: new", proclock);
4167  }
4168  else
4169  {
4170  PROCLOCK_PRINT("lock_twophase_recover: found", proclock);
4171  Assert((proclock->holdMask & ~lock->grantMask) == 0);
4172  }
4173 
4174  /*
4175  * lock->nRequested and lock->requested[] count the total number of
4176  * requests, whether granted or waiting, so increment those immediately.
4177  */
4178  lock->nRequested++;
4179  lock->requested[lockmode]++;
4180  Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
4181 
4182  /*
4183  * We shouldn't already hold the desired lock.
4184  */
4185  if (proclock->holdMask & LOCKBIT_ON(lockmode))
4186  elog(ERROR, "lock %s on object %u/%u/%u is already held",
4187  lockMethodTable->lockModeNames[lockmode],
4188  lock->tag.locktag_field1, lock->tag.locktag_field2,
4189  lock->tag.locktag_field3);
4190 
4191  /*
4192  * We ignore any possible conflicts and just grant ourselves the lock. Not
4193  * only because we don't bother, but also to avoid deadlocks when
4194  * switching from standby to normal mode. See function comment.
4195  */
4196  GrantLock(lock, proclock, lockmode);
4197 
4198  /*
4199  * Bump strong lock count, to make sure any fast-path lock requests won't
4200  * be granted without consulting the primary lock table.
4201  */
4202  if (ConflictsWithRelationFastPath(&lock->tag, lockmode))
4203  {
4204  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
4205 
4207  FastPathStrongRelationLocks->count[fasthashcode]++;
4209  }
4210 
4211  LWLockRelease(partitionLock);
4212 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:919
Definition: lwlock.h:32
int errhint(const char *fmt,...)
Definition: elog.c:974
#define ConflictsWithRelationFastPath(locktag, mode)
Definition: lock.c:205
int LOCKMODE
Definition: lockdefs.h:26
int nRequested
Definition: lock.h:299
LOCKMASK holdMask
Definition: lock.h:355
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1467
uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]
Definition: lock.c:241
LOCKTAG tag
Definition: lock.h:291
Definition: lock.h:164
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
SHM_QUEUE lockLink
Definition: lock.h:357
int errcode(int sqlerrcode)
Definition: elog.c:570
#define MemSet(start, val, len)
Definition: c.h:955
#define FastPathStrongLockHashPartition(hashcode)
Definition: lock.c:235
#define LockHashPartition(hashcode)
Definition: lock.h:501
void SHMQueueInsertBefore(SHM_QUEUE *queue, SHM_QUEUE *elem)
Definition: shmqueue.c:89
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
#define lengthof(array)
Definition: c.h:662
#define PANIC
Definition: elog.h:53
int nGranted
Definition: lock.h:301
PROC_QUEUE waitProcs
Definition: lock.h:297
LOCKTAG locktag
Definition: lock.c:160
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define SpinLockAcquire(lock)
Definition: spin.h:62
#define ERROR
Definition: elog.h:43
static volatile FastPathStrongRelationLockData * FastPathStrongRelationLocks
Definition: lock.c:244
static uint32 ProcLockHashCode(const PROCLOCKTAG *proclocktag, uint32 hashcode)
Definition: lock.c:538
void ProcQueueInit(PROC_QUEUE *queue)
Definition: proc.c:1039
uint32 locktag_field2
Definition: lock.h:167
unsigned int uint32
Definition: c.h:358
int granted[MAX_LOCKMODES]
Definition: lock.h:300
Definition: lock.h:288
PGPROC * TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
Definition: twophase.c:879
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
#define ereport(elevel, rest)
Definition: elog.h:141
LOCKMASK waitMask
Definition: lock.h:295
uint16 LOCKMETHODID
Definition: lock.h:125
SHM_QUEUE procLocks
Definition: lock.h:296
bool SHMQueueEmpty(const SHM_QUEUE *queue)
Definition: shmqueue.c:180
#define SpinLockRelease(lock)
Definition: spin.h:64
int requested[MAX_LOCKMODES]
Definition: lock.h:298
#define MAX_LOCKMODES
Definition: lock.h:85
SHM_QUEUE procLink
Definition: lock.h:358
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
#define Assert(condition)
Definition: c.h:732
static HTAB * LockMethodLockHash
Definition: lock.c:253
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
uint8 locktag_lockmethodid
Definition: lock.h:171
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
LOCKMASK grantMask
Definition: lock.h:294
Definition: lock.h:348
int errmsg(const char *fmt,...)
Definition: elog.c:784
void SHMQueueInit(SHM_QUEUE *queue)
Definition: shmqueue.c:36
#define elog(elevel,...)
Definition: elog.h:226
LOCK * myLock
Definition: lock.h:344
static const LockMethod LockMethods[]
Definition: lock.c:150
SHM_QUEUE myProcLocks[NUM_LOCK_PARTITIONS]
Definition: proc.h:160
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
uint32 locktag_field1
Definition: lock.h:166
LOCKMODE lockmode
Definition: lock.c:161
Definition: proc.h:95
uint32 locktag_field3
Definition: lock.h:168
PGPROC * lockGroupLeader
Definition: proc.h:203
const char *const * lockModeNames
Definition: lock.h:115
PGPROC * groupLeader
Definition: lock.h:354
LOCKMASK releaseMask
Definition: lock.h:356

◆ lock_twophase_standby_recover()

void lock_twophase_standby_recover ( TransactionId  xid,
uint16  info,
void *  recdata,
uint32  len 
)

Definition at line 4219 of file lock.c.

References AccessExclusiveLock, Assert, elog, ERROR, lengthof, TwoPhaseLockRecord::lockmode, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LOCKTAG_RELATION, LOCKTAG::locktag_type, and StandbyAcquireAccessExclusiveLock().

4221 {
4222  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4223  LOCKTAG *locktag;
4224  LOCKMODE lockmode;
4225  LOCKMETHODID lockmethodid;
4226 
4227  Assert(len == sizeof(TwoPhaseLockRecord));
4228  locktag = &rec->locktag;
4229  lockmode = rec->lockmode;
4230  lockmethodid = locktag->locktag_lockmethodid;
4231 
4232  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4233  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4234 
4235  if (lockmode == AccessExclusiveLock &&
4236  locktag->locktag_type == LOCKTAG_RELATION)
4237  {
4239  locktag->locktag_field1 /* dboid */ ,
4240  locktag->locktag_field2 /* reloid */ );
4241  }
4242 }
int LOCKMODE
Definition: lockdefs.h:26
Definition: lock.h:164
#define lengthof(array)
Definition: c.h:662
LOCKTAG locktag
Definition: lock.c:160
#define ERROR
Definition: elog.h:43
uint32 locktag_field2
Definition: lock.h:167
uint16 LOCKMETHODID
Definition: lock.h:125
uint8 locktag_type
Definition: lock.h:170
#define Assert(condition)
Definition: c.h:732
uint8 locktag_lockmethodid
Definition: lock.h:171
#define AccessExclusiveLock
Definition: lockdefs.h:45
void StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid)
Definition: standby.c:629
#define elog(elevel,...)
Definition: elog.h:226
static const LockMethod LockMethods[]
Definition: lock.c:150
uint32 locktag_field1
Definition: lock.h:166
LOCKMODE lockmode
Definition: lock.c:161

◆ LockAcquire()

◆ LockAcquireExtended()

LockAcquireResult LockAcquireExtended ( const LOCKTAG locktag,
LOCKMODE  lockmode,
bool  sessionLock,
bool  dontWait,
bool  reportMemoryError,
LOCALLOCK **  locallockp 
)

Definition at line 732 of file lock.c.

References AbortStrongLockAcquire(), AccessExclusiveLock, Assert, PGPROC::backendLock, BeginStrongLockAcquire(), ConflictsWithRelationFastPath, LockMethodData::conflictTab, FastPathStrongRelationLockData::count, CurrentResourceOwner, EligibleForRelationFastPath, elog, ereport, errcode(), errhint(), errmsg(), ERROR, FastPathGrantRelationLock(), FastPathLocalUseCount, FastPathStrongLockHashPartition, FastPathTransferRelationLocks(), FinishStrongLockAcquire(), FP_LOCK_SLOTS_PER_BACKEND, GrantLock(), GrantLockLocal(), HASH_ENTER, HASH_REMOVE, hash_search(), hash_search_with_hash_value(), LOCALLOCK::hashcode, PGPROC::heldLocks, PROCLOCK::holdMask, LOCALLOCK::holdsStrongLockCount, InRecovery, lengthof, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKACQUIRE_ALREADY_CLEAR, LOCKACQUIRE_ALREADY_HELD, LOCKACQUIRE_NOT_AVAIL, LOCKACQUIRE_OK, LOCKBIT_ON, LockCheckConflicts(), LOCALLOCK::lockCleared, LockHashPartitionLock, PROCLOCK::lockLink, TwoPhaseLockRecord::lockmode, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_field4, LOCKTAG::locktag_lockmethodid, LOCKTAG_OBJECT, LOCKTAG_RELATION, LOCKTAG::locktag_type, LockTagHashCode(), LOG, LogAccessExclusiveLock(), LogAccessExclusiveLockPrepare(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCK::maxLockOwners, MemoryContextAlloc(), MemSet, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, MyProc, LOCK::nGranted, LOCALLOCK::nLocks, LOCK::nRequested, LockMethodData::numLockModes, LOCALLOCK::numLockOwners, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, ProcLockHashCode(), RecoveryInProgress(), RemoveLocalLock(), repalloc(), LOCK::requested, RowExclusiveLock, SetupLockInTable(), SHMQueueDelete(), status(), STATUS_FOUND, STATUS_OK, PROCLOCK::tag, TopMemoryContext, LOCK::waitMask, WaitOnLock(), and XLogStandbyInfoActive.

Referenced by ConditionalLockRelation(), ConditionalLockRelationOid(), LockAcquire(), LockRelation(), and LockRelationOid().

738 {
739  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
740  LockMethod lockMethodTable;
741  LOCALLOCKTAG localtag;
742  LOCALLOCK *locallock;
743  LOCK *lock;
744  PROCLOCK *proclock;
745  bool found;
746  ResourceOwner owner;
747  uint32 hashcode;
748  LWLock *partitionLock;
749  int status;
750  bool log_lock = false;
751 
752  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
753  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
754  lockMethodTable = LockMethods[lockmethodid];
755  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
756  elog(ERROR, "unrecognized lock mode: %d", lockmode);
757 
758  if (RecoveryInProgress() && !InRecovery &&
759  (locktag->locktag_type == LOCKTAG_OBJECT ||
760  locktag->locktag_type == LOCKTAG_RELATION) &&
761  lockmode > RowExclusiveLock)
762  ereport(ERROR,
763  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
764  errmsg("cannot acquire lock mode %s on database objects while recovery is in progress",
765  lockMethodTable->lockModeNames[lockmode]),
766  errhint("Only RowExclusiveLock or less can be acquired on database objects during recovery.")));
767 
768 #ifdef LOCK_DEBUG
769  if (LOCK_DEBUG_ENABLED(locktag))
770  elog(LOG, "LockAcquire: lock [%u,%u] %s",
771  locktag->locktag_field1, locktag->locktag_field2,
772  lockMethodTable->lockModeNames[lockmode]);
773 #endif
774 
775  /* Identify owner for lock */
776  if (sessionLock)
777  owner = NULL;
778  else
779  owner = CurrentResourceOwner;
780 
781  /*
782  * Find or create a LOCALLOCK entry for this lock and lockmode
783  */
784  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
785  localtag.lock = *locktag;
786  localtag.mode = lockmode;
787 
788  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
789  (void *) &localtag,
790  HASH_ENTER, &found);
791 
792  /*
793  * if it's a new locallock object, initialize it
794  */
795  if (!found)
796  {
797  locallock->lock = NULL;
798  locallock->proclock = NULL;
799  locallock->hashcode = LockTagHashCode(&(localtag.lock));
800  locallock->nLocks = 0;
801  locallock->holdsStrongLockCount = false;
802  locallock->lockCleared = false;
803  locallock->numLockOwners = 0;
804  locallock->maxLockOwners = 8;
805  locallock->lockOwners = NULL; /* in case next line fails */
806  locallock->lockOwners = (LOCALLOCKOWNER *)
808  locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
809  }
810  else
811  {
812  /* Make sure there will be room to remember the lock */
813  if (locallock->numLockOwners >= locallock->maxLockOwners)
814  {
815  int newsize = locallock->maxLockOwners * 2;
816 
817  locallock->lockOwners = (LOCALLOCKOWNER *)
818  repalloc(locallock->lockOwners,
819  newsize * sizeof(LOCALLOCKOWNER));
820  locallock->maxLockOwners = newsize;
821  }
822  }
823  hashcode = locallock->hashcode;
824 
825  if (locallockp)
826  *locallockp = locallock;
827 
828  /*
829  * If we already hold the lock, we can just increase the count locally.
830  *
831  * If lockCleared is already set, caller need not worry about absorbing
832  * sinval messages related to the lock's object.
833  */
834  if (locallock->nLocks > 0)
835  {
836  GrantLockLocal(locallock, owner);
837  if (locallock->lockCleared)
839  else
841  }
842 
843  /*
844  * Prepare to emit a WAL record if acquisition of this lock needs to be
845  * replayed in a standby server.
846  *
847  * Here we prepare to log; after lock is acquired we'll issue log record.
848  * This arrangement simplifies error recovery in case the preparation step
849  * fails.
850  *
851  * Only AccessExclusiveLocks can conflict with lock types that read-only
852  * transactions can acquire in a standby server. Make sure this definition
853  * matches the one in GetRunningTransactionLocks().
854  */
855  if (lockmode >= AccessExclusiveLock &&
856  locktag->locktag_type == LOCKTAG_RELATION &&
857  !RecoveryInProgress() &&
859  {
861  log_lock = true;
862  }
863 
864  /*
865  * Attempt to take lock via fast path, if eligible. But if we remember
866  * having filled up the fast path array, we don't attempt to make any
867  * further use of it until we release some locks. It's possible that some
868  * other backend has transferred some of those locks to the shared hash
869  * table, leaving space free, but it's not worth acquiring the LWLock just
870  * to check. It's also possible that we're acquiring a second or third
871  * lock type on a relation we have already locked using the fast-path, but
872  * for now we don't worry about that case either.
873  */
874  if (EligibleForRelationFastPath(locktag, lockmode) &&
876  {
877  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
878  bool acquired;
879 
880  /*
881  * LWLockAcquire acts as a memory sequencing point, so it's safe to
882  * assume that any strong locker whose increment to
883  * FastPathStrongRelationLocks->counts becomes visible after we test
884  * it has yet to begin to transfer fast-path locks.
885  */
887  if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
888  acquired = false;
889  else
890  acquired = FastPathGrantRelationLock(locktag->locktag_field2,
891  lockmode);
893  if (acquired)
894  {
895  /*
896  * The locallock might contain stale pointers to some old shared
897  * objects; we MUST reset these to null before considering the
898  * lock to be acquired via fast-path.
899  */
900  locallock->lock = NULL;
901  locallock->proclock = NULL;
902  GrantLockLocal(locallock, owner);
903  return LOCKACQUIRE_OK;
904  }
905  }
906 
907  /*
908  * If this lock could potentially have been taken via the fast-path by
909  * some other backend, we must (temporarily) disable further use of the
910  * fast-path for this lock tag, and migrate any locks already taken via
911  * this method to the main lock table.
912  */
913  if (ConflictsWithRelationFastPath(locktag, lockmode))
914  {
915  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
916 
917  BeginStrongLockAcquire(locallock, fasthashcode);
918  if (!FastPathTransferRelationLocks(lockMethodTable, locktag,
919  hashcode))
920  {
922  if (locallock->nLocks == 0)
923  RemoveLocalLock(locallock);
924  if (locallockp)
925  *locallockp = NULL;
926  if (reportMemoryError)
927  ereport(ERROR,
928  (errcode(ERRCODE_OUT_OF_MEMORY),
929  errmsg("out of shared memory"),
930  errhint("You might need to increase max_locks_per_transaction.")));
931  else
932  return LOCKACQUIRE_NOT_AVAIL;
933  }
934  }
935 
936  /*
937  * We didn't find the lock in our LOCALLOCK table, and we didn't manage to
938  * take it via the fast-path, either, so we've got to mess with the shared
939  * lock table.
940  */
941  partitionLock = LockHashPartitionLock(hashcode);
942 
943  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
944 
945  /*
946  * Find or create lock and proclock entries with this tag
947  *
948  * Note: if the locallock object already existed, it might have a pointer
949  * to the lock already ... but we should not assume that that pointer is
950  * valid, since a lock object with zero hold and request counts can go
951  * away anytime. So we have to use SetupLockInTable() to recompute the
952  * lock and proclock pointers, even if they're already set.
953  */
954  proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
955  hashcode, lockmode);
956  if (!proclock)
957  {
959  LWLockRelease(partitionLock);
960  if (locallock->nLocks == 0)
961  RemoveLocalLock(locallock);
962  if (locallockp)
963  *locallockp = NULL;
964  if (reportMemoryError)
965  ereport(ERROR,
966  (errcode(ERRCODE_OUT_OF_MEMORY),
967  errmsg("out of shared memory"),
968  errhint("You might need to increase max_locks_per_transaction.")));
969  else
970  return LOCKACQUIRE_NOT_AVAIL;
971  }
972  locallock->proclock = proclock;
973  lock = proclock->tag.myLock;
974  locallock->lock = lock;
975 
976  /*
977  * If lock requested conflicts with locks requested by waiters, must join
978  * wait queue. Otherwise, check for conflict with already-held locks.
979  * (That's last because most complex check.)
980  */
981  if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
982  status = STATUS_FOUND;
983  else
984  status = LockCheckConflicts(lockMethodTable, lockmode,
985  lock, proclock);
986 
987  if (status == STATUS_OK)
988  {
989  /* No conflict with held or previously requested locks */
990  GrantLock(lock, proclock, lockmode);
991  GrantLockLocal(locallock, owner);
992  }
993  else
994  {
995  Assert(status == STATUS_FOUND);
996 
997  /*
998  * We can't acquire the lock immediately. If caller specified no
999  * blocking, remove useless table entries and return
1000  * LOCKACQUIRE_NOT_AVAIL without waiting.
1001  */
1002  if (dontWait)
1003  {
1005  if (proclock->holdMask == 0)
1006  {
1007  uint32 proclock_hashcode;
1008 
1009  proclock_hashcode = ProcLockHashCode(&proclock->tag, hashcode);
1010  SHMQueueDelete(&proclock->lockLink);
1011  SHMQueueDelete(&proclock->procLink);
1013  (void *) &(proclock->tag),
1014  proclock_hashcode,
1015  HASH_REMOVE,
1016  NULL))
1017  elog(PANIC, "proclock table corrupted");
1018  }
1019  else
1020  PROCLOCK_PRINT("LockAcquire: NOWAIT", proclock);
1021  lock->nRequested--;
1022  lock->requested[lockmode]--;
1023  LOCK_PRINT("LockAcquire: conditional lock failed", lock, lockmode);
1024  Assert((lock->nRequested > 0) && (lock->requested[lockmode] >= 0));
1025  Assert(lock->nGranted <= lock->nRequested);
1026  LWLockRelease(partitionLock);
1027  if (locallock->nLocks == 0)
1028  RemoveLocalLock(locallock);
1029  if (locallockp)
1030  *locallockp = NULL;
1031  return LOCKACQUIRE_NOT_AVAIL;
1032  }
1033 
1034  /*
1035  * Set bitmask of locks this process already holds on this object.
1036  */
1037  MyProc->heldLocks = proclock->holdMask;
1038 
1039  /*
1040  * Sleep till someone wakes me up.
1041  */
1042 
1043  TRACE_POSTGRESQL_LOCK_WAIT_START(locktag->locktag_field1,
1044  locktag->locktag_field2,
1045  locktag->locktag_field3,
1046  locktag->locktag_field4,
1047  locktag->locktag_type,
1048  lockmode);
1049 
1050  WaitOnLock(locallock, owner);
1051 
1052  TRACE_POSTGRESQL_LOCK_WAIT_DONE(locktag->locktag_field1,
1053  locktag->locktag_field2,
1054  locktag->locktag_field3,
1055  locktag->locktag_field4,
1056  locktag->locktag_type,
1057  lockmode);
1058 
1059  /*
1060  * NOTE: do not do any material change of state between here and
1061  * return. All required changes in locktable state must have been
1062  * done when the lock was granted to us --- see notes in WaitOnLock.
1063  */
1064 
1065  /*
1066  * Check the proclock entry status, in case something in the ipc
1067  * communication doesn't work correctly.
1068  */
1069  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
1070  {
1072  PROCLOCK_PRINT("LockAcquire: INCONSISTENT", proclock);
1073  LOCK_PRINT("LockAcquire: INCONSISTENT", lock, lockmode);
1074  /* Should we retry ? */
1075  LWLockRelease(partitionLock);
1076  elog(ERROR, "LockAcquire failed");
1077  }
1078  PROCLOCK_PRINT("LockAcquire: granted", proclock);
1079  LOCK_PRINT("LockAcquire: granted", lock, lockmode);
1080  }
1081 
1082  /*
1083  * Lock state is fully up-to-date now; if we error out after this, no
1084  * special error cleanup is required.
1085  */
1087 
1088  LWLockRelease(partitionLock);
1089 
1090  /*
1091  * Emit a WAL record if acquisition of this lock needs to be replayed in a
1092  * standby server.
1093  */
1094  if (log_lock)
1095  {
1096  /*
1097  * Decode the locktag back to the original values, to avoid sending
1098  * lots of empty bytes with every message. See lock.h to check how a
1099  * locktag is defined for LOCKTAG_RELATION
1100  */
1102  locktag->locktag_field2);
1103  }
1104 
1105  return LOCKACQUIRE_OK;
1106 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:919
PROCLOCKTAG tag
Definition: lock.h:351
uint32 hashcode
Definition: lock.h:411
Definition: lwlock.h:32
int LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
Definition: lock.c:1344
static HTAB * LockMethodLocalHash
Definition: lock.c:255
bool holdsStrongLockCount
Definition: lock.h:418
int errhint(const char *fmt,...)
Definition: elog.c:974
int numLockOwners
Definition: lock.h:415
static PROCLOCK * SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc, const LOCKTAG *locktag, uint32 hashcode, LOCKMODE lockmode)
Definition: lock.c:1119
#define ConflictsWithRelationFastPath(locktag, mode)
Definition: lock.c:205
LOCKTAG lock
Definition: lock.h:389
static bool FastPathGrantRelationLock(Oid relid, LOCKMODE lockmode)
Definition: lock.c:2564
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
int nRequested
Definition: lock.h:299
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1467
ResourceOwner CurrentResourceOwner
Definition: resowner.c:142
uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]
Definition: lock.c:241
bool InRecovery
Definition: xlog.c:200
static int FastPathLocalUseCount
Definition: lock.c:171
const LOCKMASK * conflictTab
Definition: lock.h:114
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
SHM_QUEUE lockLink
Definition: lock.h:357
void LogAccessExclusiveLock(Oid dbOid, Oid relOid)
Definition: standby.c:1039
int errcode(int sqlerrcode)
Definition: elog.c:570
#define MemSet(start, val, len)
Definition: c.h:955
#define FastPathStrongLockHashPartition(hashcode)
Definition: lock.c:235
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
#define lengthof(array)
Definition: c.h:662
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
#define LOG
Definition: elog.h:26
bool RecoveryInProgress(void)
Definition: xlog.c:7898
#define EligibleForRelationFastPath(locktag, mode)
Definition: lock.c:199
#define PANIC
Definition: elog.h:53
int maxLockOwners
Definition: lock.h:416
int nGranted
Definition: lock.h:301
static void WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
Definition: lock.c:1723
uint16 locktag_field4
Definition: lock.h:169
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define ERROR
Definition: elog.h:43
static volatile FastPathStrongRelationLockData * FastPathStrongRelationLocks
Definition: lock.c:244
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1296
static void FinishStrongLockAcquire(void)
Definition: lock.c:1656
static uint32 ProcLockHashCode(const PROCLOCKTAG *proclocktag, uint32 hashcode)
Definition: lock.c:538
#define FP_LOCK_SLOTS_PER_BACKEND
Definition: proc.h:71
#define RowExclusiveLock
Definition: lockdefs.h:38
void LogAccessExclusiveLockPrepare(void)
Definition: standby.c:1056
void AbortStrongLockAcquire(void)
Definition: lock.c:1666
uint32 locktag_field2
Definition: lock.h:167
unsigned int uint32
Definition: c.h:358
Definition: lock.h:288
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
#define ereport(elevel, rest)
Definition: elog.h:141
#define STATUS_OK
Definition: c.h:1089
MemoryContext TopMemoryContext
Definition: mcxt.c:44
LOCKMASK waitMask
Definition: lock.h:295
uint16 LOCKMETHODID
Definition: lock.h:125
int requested[MAX_LOCKMODES]
Definition: lock.h:298
SHM_QUEUE procLink
Definition: lock.h:358
static void BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
Definition: lock.c:1630
#define XLogStandbyInfoActive()
Definition: xlog.h:195
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
uint8 locktag_type
Definition: lock.h:170
#define Assert(condition)
Definition: c.h:732
#define STATUS_FOUND
Definition: c.h:1092
LWLock backendLock
Definition: proc.h:190
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
LOCK * lock
Definition: lock.h:412
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1044
uint8 locktag_lockmethodid
Definition: lock.h:171
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
#define AccessExclusiveLock
Definition: lockdefs.h:45
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
int errmsg(const char *fmt,...)
Definition: elog.c:784
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:771
#define elog(elevel,...)
Definition: elog.h:226
void SHMQueueDelete(SHM_QUEUE *queue)
Definition: shmqueue.c:68
LOCK * myLock
Definition: lock.h:344
static const LockMethod LockMethods[]
Definition: lock.c:150
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
static bool FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag, uint32 hashcode)
Definition: lock.c:2631
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227
uint32 locktag_field1
Definition: lock.h:166
uint32 locktag_field3
Definition: lock.h:168
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner)
Definition: lock.c:1601
bool lockCleared
Definition: lock.h:419
const char *const * lockModeNames
Definition: lock.h:115
LOCKMASK heldLocks
Definition: proc.h:142
int numLockModes
Definition: lock.h:113

◆ LockCheckConflicts()

int LockCheckConflicts ( LockMethod  lockMethodTable,
LOCKMODE  lockmode,
LOCK lock,
PROCLOCK proclock 
)

Definition at line 1344 of file lock.c.

References Assert, LockMethodData::conflictTab, elog, LOCK::granted, LOCK::grantMask, PROCLOCK::groupLeader, PROCLOCK::holdMask, i, LOCKBIT_ON, PGPROC::lockGroupLeader, PROCLOCK::lockLink, TwoPhaseLockRecord::lockmode, MAX_LOCKMODES, MyProc, PROCLOCKTAG::myProc, LockMethodData::numLockModes, offsetof, PANIC, PROCLOCK_PRINT, LOCK::procLocks, SHMQueueNext(), STATUS_FOUND, STATUS_OK, and PROCLOCK::tag.

Referenced by LockAcquireExtended(), ProcLockWakeup(), and ProcSleep().

1348 {
1349  int numLockModes = lockMethodTable->numLockModes;
1350  LOCKMASK myLocks;
1351  int conflictMask = lockMethodTable->conflictTab[lockmode];
1352  int conflictsRemaining[MAX_LOCKMODES];
1353  int totalConflictsRemaining = 0;
1354  int i;
1355  SHM_QUEUE *procLocks;
1356  PROCLOCK *otherproclock;
1357 
1358  /*
1359  * first check for global conflicts: If no locks conflict with my request,
1360  * then I get the lock.
1361  *
1362  * Checking for conflict: lock->grantMask represents the types of
1363  * currently held locks. conflictTable[lockmode] has a bit set for each
1364  * type of lock that conflicts with request. Bitwise compare tells if
1365  * there is a conflict.
1366  */
1367  if (!(conflictMask & lock->grantMask))
1368  {
1369  PROCLOCK_PRINT("LockCheckConflicts: no conflict", proclock);
1370  return STATUS_OK;
1371  }
1372 
1373  /*
1374  * Rats. Something conflicts. But it could still be my own lock, or a
1375  * lock held by another member of my locking group. First, figure out how
1376  * many conflicts remain after subtracting out any locks I hold myself.
1377  */
1378  myLocks = proclock->holdMask;
1379  for (i = 1; i <= numLockModes; i++)
1380  {
1381  if ((conflictMask & LOCKBIT_ON(i)) == 0)
1382  {
1383  conflictsRemaining[i] = 0;
1384  continue;
1385  }
1386  conflictsRemaining[i] = lock->granted[i];
1387  if (myLocks & LOCKBIT_ON(i))
1388  --conflictsRemaining[i];
1389  totalConflictsRemaining += conflictsRemaining[i];
1390  }
1391 
1392  /* If no conflicts remain, we get the lock. */
1393  if (totalConflictsRemaining == 0)
1394  {
1395  PROCLOCK_PRINT("LockCheckConflicts: resolved (simple)", proclock);
1396  return STATUS_OK;
1397  }
1398 
1399  /* If no group locking, it's definitely a conflict. */
1400  if (proclock->groupLeader == MyProc && MyProc->lockGroupLeader == NULL)
1401  {
1402  Assert(proclock->tag.myProc == MyProc);
1403  PROCLOCK_PRINT("LockCheckConflicts: conflicting (simple)",
1404  proclock);
1405  return STATUS_FOUND;
1406  }
1407 
1408  /*
1409  * Locks held in conflicting modes by members of our own lock group are
1410  * not real conflicts; we can subtract those out and see if we still have
1411  * a conflict. This is O(N) in the number of processes holding or
1412  * awaiting locks on this object. We could improve that by making the
1413  * shared memory state more complex (and larger) but it doesn't seem worth
1414  * it.
1415  */
1416  procLocks = &(lock->procLocks);
1417  otherproclock = (PROCLOCK *)
1418  SHMQueueNext(procLocks, procLocks, offsetof(PROCLOCK, lockLink));
1419  while (otherproclock != NULL)
1420  {
1421  if (proclock != otherproclock &&
1422  proclock->groupLeader == otherproclock->groupLeader &&
1423  (otherproclock->holdMask & conflictMask) != 0)
1424  {
1425  int intersectMask = otherproclock->holdMask & conflictMask;
1426 
1427  for (i = 1; i <= numLockModes; i++)
1428  {
1429  if ((intersectMask & LOCKBIT_ON(i)) != 0)
1430  {
1431  if (conflictsRemaining[i] <= 0)
1432  elog(PANIC, "proclocks held do not match lock");
1433  conflictsRemaining[i]--;
1434  totalConflictsRemaining--;
1435  }
1436  }
1437 
1438  if (totalConflictsRemaining == 0)
1439  {
1440  PROCLOCK_PRINT("LockCheckConflicts: resolved (group)",
1441  proclock);
1442  return STATUS_OK;
1443  }
1444  }
1445  otherproclock = (PROCLOCK *)
1446  SHMQueueNext(procLocks, &otherproclock->lockLink,
1447  offsetof(PROCLOCK, lockLink));
1448  }
1449 
1450  /* Nope, it's a real conflict. */
1451  PROCLOCK_PRINT("LockCheckConflicts: conflicting (group)", proclock);
1452  return STATUS_FOUND;
1453 }
PROCLOCKTAG tag
Definition: lock.h:351
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
const LOCKMASK * conflictTab
Definition: lock.h:114
SHM_QUEUE lockLink
Definition: lock.h:357
#define PANIC
Definition: elog.h:53
int granted[MAX_LOCKMODES]
Definition: lock.h:300
#define STATUS_OK
Definition: c.h:1089
SHM_QUEUE procLocks
Definition: lock.h:296
#define MAX_LOCKMODES
Definition: lock.h:85
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
#define Assert(condition)
Definition: c.h:732
#define STATUS_FOUND
Definition: c.h:1092
int LOCKMASK
Definition: lockdefs.h:25
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
LOCKMASK grantMask
Definition: lock.h:294
Definition: lock.h:348
#define elog(elevel,...)
Definition: elog.h:226
int i
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
PGPROC * lockGroupLeader
Definition: proc.h:203
#define offsetof(type, field)
Definition: c.h:655
PGPROC * groupLeader
Definition: lock.h:354
int numLockModes
Definition: lock.h:113

◆ LockHasWaiters()

bool LockHasWaiters ( const LOCKTAG locktag,
LOCKMODE  lockmode,
bool  sessionLock 
)

Definition at line 595 of file lock.c.

References LockMethodData::conflictTab, elog, ERROR, HASH_FIND, hash_search(), LOCALLOCK::hashcode, PROCLOCK::holdMask, lengthof, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKBIT_ON, LockHashPartitionLock, TwoPhaseLockRecord::lockmode, LockMethodData::lockModeNames, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LOG, LW_SHARED, LWLockAcquire(), LWLockRelease(), MemSet, LOCALLOCKTAG::mode, LOCALLOCK::nLocks, LockMethodData::numLockModes, LOCALLOCK::proclock, PROCLOCK_PRINT, RemoveLocalLock(), LOCK::waitMask, and WARNING.

Referenced by LockHasWaitersRelation().

596 {
597  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
598  LockMethod lockMethodTable;
599  LOCALLOCKTAG localtag;
600  LOCALLOCK *locallock;
601  LOCK *lock;
602  PROCLOCK *proclock;
603  LWLock *partitionLock;
604  bool hasWaiters = false;
605 
606  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
607  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
608  lockMethodTable = LockMethods[lockmethodid];
609  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
610  elog(ERROR, "unrecognized lock mode: %d", lockmode);
611 
612 #ifdef LOCK_DEBUG
613  if (LOCK_DEBUG_ENABLED(locktag))
614  elog(LOG, "LockHasWaiters: lock [%u,%u] %s",
615  locktag->locktag_field1, locktag->locktag_field2,
616  lockMethodTable->lockModeNames[lockmode]);
617 #endif
618 
619  /*
620  * Find the LOCALLOCK entry for this lock and lockmode
621  */
622  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
623  localtag.lock = *locktag;
624  localtag.mode = lockmode;
625 
626  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
627  (void *) &localtag,
628  HASH_FIND, NULL);
629 
630  /*
631  * let the caller print its own error message, too. Do not ereport(ERROR).
632  */
633  if (!locallock || locallock->nLocks <= 0)
634  {
635  elog(WARNING, "you don't own a lock of type %s",
636  lockMethodTable->lockModeNames[lockmode]);
637  return false;
638  }
639 
640  /*
641  * Check the shared lock table.
642  */
643  partitionLock = LockHashPartitionLock(locallock->hashcode);
644 
645  LWLockAcquire(partitionLock, LW_SHARED);
646 
647  /*
648  * We don't need to re-find the lock or proclock, since we kept their
649  * addresses in the locallock table, and they couldn't have been removed
650  * while we were holding a lock on them.
651  */
652  lock = locallock->lock;
653  LOCK_PRINT("LockHasWaiters: found", lock, lockmode);
654  proclock = locallock->proclock;
655  PROCLOCK_PRINT("LockHasWaiters: found", proclock);
656 
657  /*
658  * Double-check that we are actually holding a lock of the type we want to
659  * release.
660  */
661  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
662  {
663  PROCLOCK_PRINT("LockHasWaiters: WRONGTYPE", proclock);
664  LWLockRelease(partitionLock);
665  elog(WARNING, "you don't own a lock of type %s",
666  lockMethodTable->lockModeNames[lockmode]);
667  RemoveLocalLock(locallock);
668  return false;
669  }
670 
671  /*
672  * Do the checking.
673  */
674  if ((lockMethodTable->conflictTab[lockmode] & lock->waitMask) != 0)
675  hasWaiters = true;
676 
677  LWLockRelease(partitionLock);
678 
679  return hasWaiters;
680 }
uint32 hashcode
Definition: lock.h:411
Definition: lwlock.h:32
static HTAB * LockMethodLocalHash
Definition: lock.c:255
LOCKTAG lock
Definition: lock.h:389
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
LOCKMASK holdMask
Definition: lock.h:355
const LOCKMASK * conflictTab
Definition: lock.h:114
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
#define MemSet(start, val, len)
Definition: c.h:955
#define lengthof(array)
Definition: c.h:662
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
#define LOG
Definition: elog.h:26
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define ERROR
Definition: elog.h:43
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1296
uint32 locktag_field2
Definition: lock.h:167
Definition: lock.h:288
LOCKMASK waitMask
Definition: lock.h:295
uint16 LOCKMETHODID
Definition: lock.h:125
#define WARNING
Definition: elog.h:40
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
LOCK * lock
Definition: lock.h:412
uint8 locktag_lockmethodid
Definition: lock.h:171
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
#define elog(elevel,...)
Definition: elog.h:226
static const LockMethod LockMethods[]
Definition: lock.c:150
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
uint32 locktag_field1
Definition: lock.h:166
const char *const * lockModeNames
Definition: lock.h:115
int numLockModes
Definition: lock.h:113

◆ LockHeldByMe()

bool LockHeldByMe ( const LOCKTAG locktag,
LOCKMODE  lockmode 
)

Definition at line 571 of file lock.c.

References HASH_FIND, hash_search(), LOCALLOCKTAG::lock, TwoPhaseLockRecord::lockmode, TwoPhaseLockRecord::locktag, MemSet, LOCALLOCKTAG::mode, and LOCALLOCK::nLocks.

Referenced by CheckRelationLockedByMe().

572 {
573  LOCALLOCKTAG localtag;
574  LOCALLOCK *locallock;
575 
576  /*
577  * See if there is a LOCALLOCK entry for this lock and lockmode
578  */
579  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
580  localtag.lock = *locktag;
581  localtag.mode = lockmode;
582 
583  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
584  (void *) &localtag,
585  HASH_FIND, NULL);
586 
587  return (locallock && locallock->nLocks > 0);
588 }
static HTAB * LockMethodLocalHash
Definition: lock.c:255
LOCKTAG lock
Definition: lock.h:389
LOCKMODE mode
Definition: lock.h:390
#define MemSet(start, val, len)
Definition: c.h:955
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
int64 nLocks
Definition: lock.h:414

◆ LockReassignCurrentOwner()

void LockReassignCurrentOwner ( LOCALLOCK **  locallocks,
int  nlocks 
)

Definition at line 2488 of file lock.c.

References Assert, CurrentResourceOwner, hash_seq_init(), hash_seq_search(), i, LockReassignOwner(), ResourceOwnerGetParent(), and status().

Referenced by ResourceOwnerReleaseInternal().

2489 {
2491 
2492  Assert(parent != NULL);
2493 
2494  if (locallocks == NULL)
2495  {
2497  LOCALLOCK *locallock;
2498 
2500 
2501  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2502  LockReassignOwner(locallock, parent);
2503  }
2504  else
2505  {
2506  int i;
2507 
2508  for (i = nlocks - 1; i >= 0; i--)
2509  LockReassignOwner(locallocks[i], parent);
2510  }
2511 }
static void LockReassignOwner(LOCALLOCK *locallock, ResourceOwner parent)
Definition: lock.c:2518
static HTAB * LockMethodLocalHash
Definition: lock.c:255
ResourceOwner CurrentResourceOwner
Definition: resowner.c:142
ResourceOwner ResourceOwnerGetParent(ResourceOwner owner)
Definition: resowner.c:739
#define Assert(condition)
Definition: c.h:732
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
int i
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227

◆ LockRelease()

bool LockRelease ( const LOCKTAG locktag,
LOCKMODE  lockmode,
bool  sessionLock 
)

Definition at line 1884 of file lock.c.

References Assert, PGPROC::backendLock, CleanUpLock(), CurrentResourceOwner, EligibleForRelationFastPath, elog, ERROR, FastPathLocalUseCount, FastPathUnGrantRelationLock(), HASH_FIND, hash_search(), hash_search_with_hash_value(), LOCALLOCK::hashcode, PROCLOCK::holdMask, i, lengthof, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKBIT_ON, LOCALLOCK::lockCleared, LockHashPartitionLock, TwoPhaseLockRecord::lockmode, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MemSet, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, MyProc, PROCLOCKTAG::myProc, LOCALLOCK::nLocks, LockMethodData::numLockModes, LOCALLOCK::numLockOwners, LOCALLOCK::proclock, PROCLOCK_PRINT, RemoveLocalLock(), ResourceOwnerForgetLock(), UnGrantLock(), and WARNING.

Referenced by ConditionalXactLockTableWait(), pg_advisory_unlock_int4(), pg_advisory_unlock_int8(), pg_advisory_unlock_shared_int4(), pg_advisory_unlock_shared_int8(), ReleaseLockIfHeld(), SpeculativeInsertionLockRelease(), SpeculativeInsertionWait(), StandbyReleaseLockList(), UnlockDatabaseObject(), UnlockPage(), UnlockRelation(), UnlockRelationForExtension(), UnlockRelationId(), UnlockRelationIdForSession(), UnlockRelationOid(), UnlockSharedObject(), UnlockSharedObjectForSession(), UnlockTuple(), VirtualXactLock(), XactLockTableDelete(), and XactLockTableWait().

1885 {
1886  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
1887  LockMethod lockMethodTable;
1888  LOCALLOCKTAG localtag;
1889  LOCALLOCK *locallock;
1890  LOCK *lock;
1891  PROCLOCK *proclock;
1892  LWLock *partitionLock;
1893  bool wakeupNeeded;
1894 
1895  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
1896  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
1897  lockMethodTable = LockMethods[lockmethodid];
1898  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
1899  elog(ERROR, "unrecognized lock mode: %d", lockmode);
1900 
1901 #ifdef LOCK_DEBUG
1902  if (LOCK_DEBUG_ENABLED(locktag))
1903  elog(LOG, "LockRelease: lock [%u,%u] %s",
1904  locktag->locktag_field1, locktag->locktag_field2,
1905  lockMethodTable->lockModeNames[lockmode]);
1906 #endif
1907 
1908  /*
1909  * Find the LOCALLOCK entry for this lock and lockmode
1910  */
1911  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
1912  localtag.lock = *locktag;
1913  localtag.mode = lockmode;
1914 
1915  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
1916  (void *) &localtag,
1917  HASH_FIND, NULL);
1918 
1919  /*
1920  * let the caller print its own error message, too. Do not ereport(ERROR).
1921  */
1922  if (!locallock || locallock->nLocks <= 0)
1923  {
1924  elog(WARNING, "you don't own a lock of type %s",
1925  lockMethodTable->lockModeNames[lockmode]);
1926  return false;
1927  }
1928 
1929  /*
1930  * Decrease the count for the resource owner.
1931  */
1932  {
1933  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
1934  ResourceOwner owner;
1935  int i;
1936 
1937  /* Identify owner for lock */
1938  if (sessionLock)
1939  owner = NULL;
1940  else
1941  owner = CurrentResourceOwner;
1942 
1943  for (i = locallock->numLockOwners - 1; i >= 0; i--)
1944  {
1945  if (lockOwners[i].owner == owner)
1946  {
1947  Assert(lockOwners[i].nLocks > 0);
1948  if (--lockOwners[i].nLocks == 0)
1949  {
1950  if (owner != NULL)
1951  ResourceOwnerForgetLock(owner, locallock);
1952  /* compact out unused slot */
1953  locallock->numLockOwners--;
1954  if (i < locallock->numLockOwners)
1955  lockOwners[i] = lockOwners[locallock->numLockOwners];
1956  }
1957  break;
1958  }
1959  }
1960  if (i < 0)
1961  {
1962  /* don't release a lock belonging to another owner */
1963  elog(WARNING, "you don't own a lock of type %s",
1964  lockMethodTable->lockModeNames[lockmode]);
1965  return false;
1966  }
1967  }
1968 
1969  /*
1970  * Decrease the total local count. If we're still holding the lock, we're
1971  * done.
1972  */
1973  locallock->nLocks--;
1974 
1975  if (locallock->nLocks > 0)
1976  return true;
1977 
1978  /*
1979  * At this point we can no longer suppose we are clear of invalidation
1980  * messages related to this lock. Although we'll delete the LOCALLOCK
1981  * object before any intentional return from this routine, it seems worth
1982  * the trouble to explicitly reset lockCleared right now, just in case
1983  * some error prevents us from deleting the LOCALLOCK.
1984  */
1985  locallock->lockCleared = false;
1986 
1987  /* Attempt fast release of any lock eligible for the fast path. */
1988  if (EligibleForRelationFastPath(locktag, lockmode) &&
1990  {
1991  bool released;
1992 
1993  /*
1994  * We might not find the lock here, even if we originally entered it
1995  * here. Another backend may have moved it to the main table.
1996  */
1998  released = FastPathUnGrantRelationLock(locktag->locktag_field2,
1999  lockmode);
2001  if (released)
2002  {
2003  RemoveLocalLock(locallock);
2004  return true;
2005  }
2006  }
2007 
2008  /*
2009  * Otherwise we've got to mess with the shared lock table.
2010  */
2011  partitionLock = LockHashPartitionLock(locallock->hashcode);
2012 
2013  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2014 
2015  /*
2016  * Normally, we don't need to re-find the lock or proclock, since we kept
2017  * their addresses in the locallock table, and they couldn't have been
2018  * removed while we were holding a lock on them. But it's possible that
2019  * the lock was taken fast-path and has since been moved to the main hash
2020  * table by another backend, in which case we will need to look up the
2021  * objects here. We assume the lock field is NULL if so.
2022  */
2023  lock = locallock->lock;
2024  if (!lock)
2025  {
2026  PROCLOCKTAG proclocktag;
2027 
2028  Assert(EligibleForRelationFastPath(locktag, lockmode));
2030  (const void *) locktag,
2031  locallock->hashcode,
2032  HASH_FIND,
2033  NULL);
2034  if (!lock)
2035  elog(ERROR, "failed to re-find shared lock object");
2036  locallock->lock = lock;
2037 
2038  proclocktag.myLock = lock;
2039  proclocktag.myProc = MyProc;
2041  (void *) &proclocktag,
2042  HASH_FIND,
2043  NULL);
2044  if (!locallock->proclock)
2045  elog(ERROR, "failed to re-find shared proclock object");
2046  }
2047  LOCK_PRINT("LockRelease: found", lock, lockmode);
2048  proclock = locallock->proclock;
2049  PROCLOCK_PRINT("LockRelease: found", proclock);
2050 
2051  /*
2052  * Double-check that we are actually holding a lock of the type we want to
2053  * release.
2054  */
2055  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
2056  {
2057  PROCLOCK_PRINT("LockRelease: WRONGTYPE", proclock);
2058  LWLockRelease(partitionLock);
2059  elog(WARNING, "you don't own a lock of type %s",
2060  lockMethodTable->lockModeNames[lockmode]);
2061  RemoveLocalLock(locallock);
2062  return false;
2063  }
2064 
2065  /*
2066  * Do the releasing. CleanUpLock will waken any now-wakable waiters.
2067  */
2068  wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
2069 
2070  CleanUpLock(lock, proclock,
2071  lockMethodTable, locallock->hashcode,
2072  wakeupNeeded);
2073 
2074  LWLockRelease(partitionLock);
2075 
2076  RemoveLocalLock(locallock);
2077  return true;
2078 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:919
uint32 hashcode
Definition: lock.h:411
Definition: lwlock.h:32
static HTAB * LockMethodLocalHash
Definition: lock.c:255
int numLockOwners
Definition: lock.h:415
static bool FastPathUnGrantRelationLock(Oid relid, LOCKMODE lockmode)
Definition: lock.c:2601
LOCKTAG lock
Definition: lock.h:389
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
ResourceOwner CurrentResourceOwner
Definition: resowner.c:142
static int FastPathLocalUseCount
Definition: lock.c:171
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
#define MemSet(start, val, len)
Definition: c.h:955
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
#define lengthof(array)
Definition: c.h:662
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:906
#define LOG
Definition: elog.h:26
#define EligibleForRelationFastPath(locktag, mode)
Definition: lock.c:199
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define ERROR
Definition: elog.h:43
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1296
uint32 locktag_field2
Definition: lock.h:167
Definition: lock.h:288
uint16 LOCKMETHODID
Definition: lock.h:125
#define WARNING
Definition: elog.h:40
void ResourceOwnerForgetLock(ResourceOwner owner, LOCALLOCK *locallock)
Definition: resowner.c:953
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
#define Assert(condition)
Definition: c.h:732
LWLock backendLock
Definition: proc.h:190
static HTAB * LockMethodLockHash
Definition: lock.c:253
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
LOCK * lock
Definition: lock.h:412
uint8 locktag_lockmethodid
Definition: lock.h:171
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
#define elog(elevel,...)
Definition: elog.h:226
int i
LOCK * myLock
Definition: lock.h:344
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode, PROCLOCK *proclock, LockMethod lockMethodTable)
Definition: lock.c:1490
static const LockMethod LockMethods[]
Definition: lock.c:150
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock, LockMethod lockMethodTable, uint32 hashcode, bool wakeupNeeded)
Definition: lock.c:1547
uint32 locktag_field1
Definition: lock.h:166
bool lockCleared
Definition: lock.h:419
const char *const * lockModeNames
Definition: lock.h:115
int numLockModes
Definition: lock.h:113

◆ LockReleaseAll()

void LockReleaseAll ( LOCKMETHODID  lockmethodid,
bool  allLocks 
)

Definition at line 2089 of file lock.c.

References Assert, PGPROC::backendLock, CleanUpLock(), DEFAULT_LOCKMETHOD, EligibleForRelationFastPath, elog, ERROR, FastPathUnGrantRelationLock(), LOCK::grantMask, hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, i, lengthof, LOCALLOCK_LOCKMETHOD, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_LOCKMETHOD, LOCK_PRINT, LOCKBIT_ON, LockHashPartitionLockByIndex, TwoPhaseLockRecord::lockmode, LOCALLOCK::lockOwners, LockRefindAndRelease(), LOCKTAG::locktag_field2, LockTagHashCode(), LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, MyProc, PROCLOCKTAG::myProc, PGPROC::myProcLocks, LOCK::nGranted, LOCALLOCKOWNER::nLocks, LOCALLOCK::nLocks, LOCK::nRequested, NUM_LOCK_PARTITIONS, LockMethodData::numLockModes, LOCALLOCK::numLockOwners, offsetof, LOCALLOCKOWNER::owner, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), ResourceOwnerForgetLock(), SHMQueueNext(), status(), LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, LockMethodData::trace_flag, UnGrantLock(), and VirtualXactLockTableCleanup().

Referenced by DiscardAll(), ProcReleaseLocks(), and ShutdownPostgres().

2090 {
2092  LockMethod lockMethodTable;
2093  int i,
2094  numLockModes;
2095  LOCALLOCK *locallock;
2096  LOCK *lock;
2097  PROCLOCK *proclock;
2098  int partition;
2099  bool have_fast_path_lwlock = false;
2100 
2101  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2102  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2103  lockMethodTable = LockMethods[lockmethodid];
2104 
2105 #ifdef LOCK_DEBUG
2106  if (*(lockMethodTable->trace_flag))
2107  elog(LOG, "LockReleaseAll: lockmethod=%d", lockmethodid);
2108 #endif
2109 
2110  /*
2111  * Get rid of our fast-path VXID lock, if appropriate. Note that this is
2112  * the only way that the lock we hold on our own VXID can ever get
2113  * released: it is always and only released when a toplevel transaction
2114  * ends.
2115  */
2116  if (lockmethodid == DEFAULT_LOCKMETHOD)
2118 
2119  numLockModes = lockMethodTable->numLockModes;
2120 
2121  /*
2122  * First we run through the locallock table and get rid of unwanted
2123  * entries, then we scan the process's proclocks and get rid of those. We
2124  * do this separately because we may have multiple locallock entries
2125  * pointing to the same proclock, and we daren't end up with any dangling
2126  * pointers. Fast-path locks are cleaned up during the locallock table
2127  * scan, though.
2128  */
2130 
2131  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2132  {
2133  /*
2134  * If the LOCALLOCK entry is unused, we must've run out of shared
2135  * memory while trying to set up this lock. Just forget the local
2136  * entry.
2137  */
2138  if (locallock->nLocks == 0)
2139  {
2140  RemoveLocalLock(locallock);
2141  continue;
2142  }
2143 
2144  /* Ignore items that are not of the lockmethod to be removed */
2145  if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2146  continue;
2147 
2148  /*
2149  * If we are asked to release all locks, we can just zap the entry.
2150  * Otherwise, must scan to see if there are session locks. We assume
2151  * there is at most one lockOwners entry for session locks.
2152  */
2153  if (!allLocks)
2154  {
2155  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
2156 
2157  /* If session lock is above array position 0, move it down to 0 */
2158  for (i = 0; i < locallock->numLockOwners; i++)
2159  {
2160  if (lockOwners[i].owner == NULL)
2161  lockOwners[0] = lockOwners[i];
2162  else
2163  ResourceOwnerForgetLock(lockOwners[i].owner, locallock);
2164  }
2165 
2166  if (locallock->numLockOwners > 0 &&
2167  lockOwners[0].owner == NULL &&
2168  lockOwners[0].nLocks > 0)
2169  {
2170  /* Fix the locallock to show just the session locks */
2171  locallock->nLocks = lockOwners[0].nLocks;
2172  locallock->numLockOwners = 1;
2173  /* We aren't deleting this locallock, so done */
2174  continue;
2175  }
2176  else
2177  locallock->numLockOwners = 0;
2178  }
2179 
2180  /*
2181  * If the lock or proclock pointers are NULL, this lock was taken via
2182  * the relation fast-path (and is not known to have been transferred).
2183  */
2184  if (locallock->proclock == NULL || locallock->lock == NULL)
2185  {
2186  LOCKMODE lockmode = locallock->tag.mode;
2187  Oid relid;
2188 
2189  /* Verify that a fast-path lock is what we've got. */
2190  if (!EligibleForRelationFastPath(&locallock->tag.lock, lockmode))
2191  elog(PANIC, "locallock table corrupted");
2192 
2193  /*
2194  * If we don't currently hold the LWLock that protects our
2195  * fast-path data structures, we must acquire it before attempting
2196  * to release the lock via the fast-path. We will continue to
2197  * hold the LWLock until we're done scanning the locallock table,
2198  * unless we hit a transferred fast-path lock. (XXX is this
2199  * really such a good idea? There could be a lot of entries ...)
2200  */
2201  if (!have_fast_path_lwlock)
2202  {
2204  have_fast_path_lwlock = true;
2205  }
2206 
2207  /* Attempt fast-path release. */
2208  relid = locallock->tag.lock.locktag_field2;
2209  if (FastPathUnGrantRelationLock(relid, lockmode))
2210  {
2211  RemoveLocalLock(locallock);
2212  continue;
2213  }
2214 
2215  /*
2216  * Our lock, originally taken via the fast path, has been
2217  * transferred to the main lock table. That's going to require
2218  * some extra work, so release our fast-path lock before starting.
2219  */
2221  have_fast_path_lwlock = false;
2222 
2223  /*
2224  * Now dump the lock. We haven't got a pointer to the LOCK or
2225  * PROCLOCK in this case, so we have to handle this a bit
2226  * differently than a normal lock release. Unfortunately, this
2227  * requires an extra LWLock acquire-and-release cycle on the
2228  * partitionLock, but hopefully it shouldn't happen often.
2229  */
2230  LockRefindAndRelease(lockMethodTable, MyProc,
2231  &locallock->tag.lock, lockmode, false);
2232  RemoveLocalLock(locallock);
2233  continue;
2234  }
2235 
2236  /* Mark the proclock to show we need to release this lockmode */
2237  if (locallock->nLocks > 0)
2238  locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
2239 
2240  /* And remove the locallock hashtable entry */
2241  RemoveLocalLock(locallock);
2242  }
2243 
2244  /* Done with the fast-path data structures */
2245  if (have_fast_path_lwlock)
2247 
2248  /*
2249  * Now, scan each lock partition separately.
2250  */
2251  for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
2252  {
2253  LWLock *partitionLock;
2254  SHM_QUEUE *procLocks = &(MyProc->myProcLocks[partition]);
2255  PROCLOCK *nextplock;
2256 
2257  partitionLock = LockHashPartitionLockByIndex(partition);
2258 
2259  /*
2260  * If the proclock list for this partition is empty, we can skip
2261  * acquiring the partition lock. This optimization is trickier than
2262  * it looks, because another backend could be in process of adding
2263  * something to our proclock list due to promoting one of our
2264  * fast-path locks. However, any such lock must be one that we
2265  * decided not to delete above, so it's okay to skip it again now;
2266  * we'd just decide not to delete it again. We must, however, be
2267  * careful to re-fetch the list header once we've acquired the
2268  * partition lock, to be sure we have a valid, up-to-date pointer.
2269  * (There is probably no significant risk if pointer fetch/store is
2270  * atomic, but we don't wish to assume that.)
2271  *
2272  * XXX This argument assumes that the locallock table correctly
2273  * represents all of our fast-path locks. While allLocks mode
2274  * guarantees to clean up all of our normal locks regardless of the
2275  * locallock situation, we lose that guarantee for fast-path locks.
2276  * This is not ideal.
2277  */
2278  if (SHMQueueNext(procLocks, procLocks,
2279  offsetof(PROCLOCK, procLink)) == NULL)
2280  continue; /* needn't examine this partition */
2281 
2282  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2283 
2284  for (proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
2285  offsetof(PROCLOCK, procLink));
2286  proclock;
2287  proclock = nextplock)
2288  {
2289  bool wakeupNeeded = false;
2290 
2291  /* Get link first, since we may unlink/delete this proclock */
2292  nextplock = (PROCLOCK *)
2293  SHMQueueNext(procLocks, &proclock->procLink,
2294  offsetof(PROCLOCK, procLink));
2295 
2296  Assert(proclock->tag.myProc == MyProc);
2297 
2298  lock = proclock->tag.myLock;
2299 
2300  /* Ignore items that are not of the lockmethod to be removed */
2301  if (LOCK_LOCKMETHOD(*lock) != lockmethodid)
2302  continue;
2303 
2304  /*
2305  * In allLocks mode, force release of all locks even if locallock
2306  * table had problems
2307  */
2308  if (allLocks)
2309  proclock->releaseMask = proclock->holdMask;
2310  else
2311  Assert((proclock->releaseMask & ~proclock->holdMask) == 0);
2312 
2313  /*
2314  * Ignore items that have nothing to be released, unless they have
2315  * holdMask == 0 and are therefore recyclable
2316  */
2317  if (proclock->releaseMask == 0 && proclock->holdMask != 0)
2318  continue;
2319 
2320  PROCLOCK_PRINT("LockReleaseAll", proclock);
2321  LOCK_PRINT("LockReleaseAll", lock, 0);
2322  Assert(lock->nRequested >= 0);
2323  Assert(lock->nGranted >= 0);
2324  Assert(lock->nGranted <= lock->nRequested);
2325  Assert((proclock->holdMask & ~lock->grantMask) == 0);
2326 
2327  /*
2328  * Release the previously-marked lock modes
2329  */
2330  for (i = 1; i <= numLockModes; i++)
2331  {
2332  if (proclock->releaseMask & LOCKBIT_ON(i))
2333  wakeupNeeded |= UnGrantLock(lock, i, proclock,
2334  lockMethodTable);
2335  }
2336  Assert((lock->nRequested >= 0) && (lock->nGranted >= 0));
2337  Assert(lock->nGranted <= lock->nRequested);
2338  LOCK_PRINT("LockReleaseAll: updated", lock, 0);
2339 
2340  proclock->releaseMask = 0;
2341 
2342  /* CleanUpLock will wake up waiters if needed. */
2343  CleanUpLock(lock, proclock,
2344  lockMethodTable,
2345  LockTagHashCode(&lock->tag),
2346  wakeupNeeded);
2347  } /* loop over PROCLOCKs within this partition */
2348 
2349  LWLockRelease(partitionLock);
2350  } /* loop over partitions */
2351 
2352 #ifdef LOCK_DEBUG
2353  if (*(lockMethodTable->trace_flag))
2354  elog(LOG, "LockReleaseAll done");
2355 #endif
2356 }
PROCLOCKTAG tag
Definition: lock.h:351
Definition: lwlock.h:32
LOCALLOCKTAG tag
Definition: lock.h:408
static HTAB * LockMethodLocalHash
Definition: lock.c:255
static void LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, LOCKTAG *locktag, LOCKMODE lockmode, bool decrement_strong_lock_count)
Definition: lock.c:3042
void VirtualXactLockTableCleanup(void)
Definition: lock.c:4324
int numLockOwners
Definition: lock.h:415
static bool FastPathUnGrantRelationLock(Oid relid, LOCKMODE lockmode)
Definition: lock.c:2601
LOCKTAG lock
Definition: lock.h:389
int LOCKMODE
Definition: lockdefs.h:26
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
int nRequested
Definition: lock.h:299
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
int64 nLocks
Definition: lock.h:402
LOCKTAG tag
Definition: lock.h:291
#define lengthof(array)
Definition: c.h:662
#define LOG
Definition: elog.h:26
unsigned int Oid
Definition: postgres_ext.h:31
#define EligibleForRelationFastPath(locktag, mode)
Definition: lock.c:199
#define PANIC
Definition: elog.h:53
int nGranted
Definition: lock.h:301
#define DEFAULT_LOCKMETHOD
Definition: lock.h:128
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:506
#define ERROR
Definition: elog.h:43
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1296
uint32 locktag_field2
Definition: lock.h:167
Definition: lock.h:288
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
#define LOCALLOCK_LOCKMETHOD(llock)
Definition: lock.h:422
SHM_QUEUE procLink
Definition: lock.h:358
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
void ResourceOwnerForgetLock(ResourceOwner owner, LOCALLOCK *locallock)
Definition: resowner.c:953
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
#define Assert(condition)
Definition: c.h:732
LWLock backendLock
Definition: proc.h:190
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
LOCK * lock
Definition: lock.h:412
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
LOCKMASK grantMask
Definition: lock.h:294
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
#define elog(elevel,...)
Definition: elog.h:226
int i
const bool * trace_flag
Definition: lock.h:116
LOCK * myLock
Definition: lock.h:344
struct ResourceOwnerData * owner
Definition: lock.h:401
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode, PROCLOCK *proclock, LockMethod lockMethodTable)
Definition: lock.c:1490
static const LockMethod LockMethods[]
Definition: lock.c:150
SHM_QUEUE myProcLocks[NUM_LOCK_PARTITIONS]
Definition: proc.h:160
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:338
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock, LockMethod lockMethodTable, uint32 hashcode, bool wakeupNeeded)
Definition: lock.c:1547
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227
#define offsetof(type, field)
Definition: c.h:655
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:117
#define LOCK_LOCKMETHOD(lock)
Definition: lock.h:304
int numLockModes
Definition: lock.h:113
LOCKMASK releaseMask
Definition: lock.h:356

◆ LockReleaseCurrentOwner()

void LockReleaseCurrentOwner ( LOCALLOCK **  locallocks,
int  nlocks 
)

Definition at line 2393 of file lock.c.

References hash_seq_init(), hash_seq_search(), i, ReleaseLockIfHeld(), and status().

Referenced by ResourceOwnerReleaseInternal().

2394 {
2395  if (locallocks == NULL)
2396  {
2398  LOCALLOCK *locallock;
2399 
2401 
2402  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2403  ReleaseLockIfHeld(locallock, false);
2404  }
2405  else
2406  {
2407  int i;
2408 
2409  for (i = nlocks - 1; i >= 0; i--)
2410  ReleaseLockIfHeld(locallocks[i], false);
2411  }
2412 }
static HTAB * LockMethodLocalHash
Definition: lock.c:255
static void ReleaseLockIfHeld(LOCALLOCK *locallock, bool sessionLock)
Definition: lock.c:2428
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
int i
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227

◆ LockReleaseSession()

void LockReleaseSession ( LOCKMETHODID  lockmethodid)

Definition at line 2363 of file lock.c.

References elog, ERROR, hash_seq_init(), hash_seq_search(), lengthof, LOCALLOCK_LOCKMETHOD, ReleaseLockIfHeld(), and status().

Referenced by pg_advisory_unlock_all().

2364 {
2366  LOCALLOCK *locallock;
2367 
2368  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2369  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2370 
2372 
2373  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2374  {
2375  /* Ignore items that are not of the specified lock method */
2376  if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2377  continue;
2378 
2379  ReleaseLockIfHeld(locallock, true);
2380  }
2381 }
static HTAB * LockMethodLocalHash
Definition: lock.c:255
#define lengthof(array)
Definition: c.h:662
#define ERROR
Definition: elog.h:43
static void ReleaseLockIfHeld(LOCALLOCK *locallock, bool sessionLock)
Definition: lock.c:2428
#define LOCALLOCK_LOCKMETHOD(llock)
Definition: lock.h:422
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
#define elog(elevel,...)
Definition: elog.h:226
static const LockMethod LockMethods[]
Definition: lock.c:150
static void static void status(const char *fmt,...) pg_attribute_printf(1
Definition: pg_regress.c:227

◆ LockShmemSize()

Size LockShmemSize ( void  )

Definition at line 3441 of file lock.c.

References add_size(), hash_estimate_size(), and NLOCKENTS.

Referenced by CreateSharedMemoryAndSemaphores().

3442 {
3443  Size size = 0;
3444  long max_table_size;
3445 
3446  /* lock hash table */
3447  max_table_size = NLOCKENTS();
3448  size = add_size(size, hash_estimate_size(max_table_size, sizeof(LOCK)));
3449 
3450  /* proclock hash table */
3451  max_table_size *= 2;
3452  size = add_size(size, hash_estimate_size(max_table_size, sizeof(PROCLOCK)));
3453 
3454  /*
3455  * Since NLOCKENTS is only an estimate, add 10% safety margin.
3456  */
3457  size = add_size(size, size / 10);
3458 
3459  return size;
3460 }
#define NLOCKENTS()
Definition: lock.c:56
Definition: lock.h:288
Size hash_estimate_size(long num_entries, Size entrysize)
Definition: dynahash.c:732
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
size_t Size
Definition: c.h:466
Definition: lock.h:348

◆ LockTagHashCode()

uint32 LockTagHashCode ( const LOCKTAG locktag)

Definition at line 490 of file lock.c.

References get_hash_value().

Referenced by CheckDeadLock(), GetLockConflicts(), lock_twophase_recover(), LockAcquireExtended(), LockRefindAndRelease(), LockReleaseAll(), LockWaiterCount(), proclock_hash(), and VirtualXactLock().

491 {
492  return get_hash_value(LockMethodLockHash, (const void *) locktag);
493 }
uint32 get_hash_value(HTAB *hashp, const void *keyPtr)
Definition: dynahash.c:860
static HTAB * LockMethodLockHash
Definition: lock.c:253

◆ LockWaiterCount()

int LockWaiterCount ( const LOCKTAG locktag)

Definition at line 4467 of file lock.c.

References Assert, elog, ERROR, HASH_FIND, hash_search_with_hash_value(), lengthof, LockHashPartitionLock, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), and LOCK::nRequested.

Referenced by RelationExtensionLockWaiterCount().

4468 {
4469  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
4470  LOCK *lock;
4471  bool found;
4472  uint32 hashcode;
4473  LWLock *partitionLock;
4474  int waiters = 0;
4475 
4476  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4477  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4478 
4479  hashcode = LockTagHashCode(locktag);
4480  partitionLock = LockHashPartitionLock(hashcode);
4481  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4482 
4484  (const void *) locktag,
4485  hashcode,
4486  HASH_FIND,
4487  &found);
4488  if (found)
4489  {
4490  Assert(lock != NULL);
4491  waiters = lock->nRequested;
4492  }
4493  LWLockRelease(partitionLock);
4494 
4495  return waiters;
4496 }
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:919
Definition: lwlock.h:32
int nRequested
Definition: lock.h:299
#define LockHashPartitionLock(hashcode)
Definition: lock.h:503
#define lengthof(array)
Definition: c.h:662
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define ERROR
Definition: elog.h:43
unsigned int uint32
Definition: c.h:358
Definition: lock.h:288
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
uint16 LOCKMETHODID
Definition: lock.h:125
#define Assert(condition)
Definition: c.h:732
static HTAB * LockMethodLockHash
Definition: lock.c:253
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
uint8 locktag_lockmethodid
Definition: lock.h:171
#define elog(elevel,...)
Definition: elog.h:226
static const LockMethod LockMethods[]
Definition: lock.c:150

◆ MarkLockClear()

void MarkLockClear ( LOCALLOCK locallock)

Definition at line 1708 of file lock.c.

References Assert, LOCALLOCK::lockCleared, and LOCALLOCK::nLocks.

Referenced by ConditionalLockRelation(), ConditionalLockRelationOid(), LockRelation(), and LockRelationOid().

1709 {
1710  Assert(locallock->nLocks > 0);
1711  locallock->lockCleared = true;
1712 }
#define Assert(condition)
Definition: c.h:732
int64 nLocks
Definition: lock.h:414
bool lockCleared
Definition: lock.h:419

◆ PostPrepare_Locks()

void PostPrepare_Locks ( TransactionId  xid)

Definition at line 3249 of file lock.c.

References Assert, elog, END_CRIT_SECTION, ereport, errcode(), errmsg(), LOCK::grantMask, PROCLOCK::groupLeader, hash_seq_init(), hash_seq_search(), hash_update_hash_key(), PROCLOCK::holdMask, i, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKBIT_ON, PGPROC::lockGroupLeader, LockHashPartitionLockByIndex, LOCALLOCK::lockOwners, LOCKTAG::locktag_type, LOCKTAG_VIRTUALTRANSACTION, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, MyProc, PROCLOCKTAG::myProc, PGPROC::myProcLocks, LOCK::nGranted, LOCALLOCK::nLocks, LOCK::nRequested, NUM_LOCK_PARTITIONS, LOCALLOCK::numLockOwners, offsetof, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), SHMQueueDelete(), SHMQueueInsertBefore(), SHMQueueNext(), START_CRIT_SECTION, status(), LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, and TwoPhaseGetDummyProc().

Referenced by PrepareTransaction().

3250 {
3251  PGPROC *newproc = TwoPhaseGetDummyProc(xid, false);
3253  LOCALLOCK *locallock;
3254  LOCK *lock;
3255  PROCLOCK *proclock;
3256  PROCLOCKTAG proclocktag;
3257  int partition;
3258 
3259  /* Can't prepare a lock group follower. */
3260  Assert(MyProc->lockGroupLeader == NULL ||
3262 
3263  /* This is a critical section: any error means big trouble */
3265 
3266  /*
3267  * First we run through the locallock table and get rid of unwanted
3268  * entries, then we scan the process's proclocks and transfer them to the
3269  * target proc.
3270  *
3271  * We do this separately because we may have multiple locallock entries
3272  * pointing to the same proclock, and we daren't end up with any dangling
3273  * pointers.
3274  */
3276 
3277  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3278  {
3279  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3280  bool haveSessionLock;
3281  bool haveXactLock;
3282  int i;
3283 
3284  if (locallock->proclock == NULL || locallock->lock == NULL)
3285  {
3286  /*
3287  * We must've run out of shared memory while trying to set up this
3288  * lock. Just forget the local entry.
3289  */
3290  Assert(locallock->nLocks == 0);
3291  RemoveLocalLock(locallock);
3292  continue;
3293  }
3294 
3295  /* Ignore VXID locks */
3296  if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3297  continue;
3298 
3299  /* Scan to see whether we hold it at session or transaction level */
3300  haveSessionLock = haveXactLock = false;
3301  for (i = locallock->numLockOwners - 1; i >= 0; i--)
3302  {
3303  if (lockOwners[i].owner == NULL)
3304  haveSessionLock = true;
3305  else
3306  haveXactLock = true;
3307  }
3308 
3309  /* Ignore it if we have only session lock */
3310  if (!haveXactLock)
3311  continue;
3312 
3313  /* This can't happen, because we already checked it */
3314  if (haveSessionLock)
3315  ereport(PANIC,
3316  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3317  errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3318 
3319  /* Mark the proclock to show we need to release this lockmode */
3320  if (locallock->nLocks > 0)
3321  locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
3322 
3323  /* And remove the locallock hashtable entry */
3324  RemoveLocalLock(locallock);
3325  }
3326 
3327  /*
3328  * Now, scan each lock partition separately.
3329  */
3330  for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
3331  {
3332  LWLock *partitionLock;
3333  SHM_QUEUE *procLocks = &(MyProc->myProcLocks[partition]);
3334  PROCLOCK *nextplock;
3335 
3336  partitionLock = LockHashPartitionLockByIndex(partition);
3337 
3338  /*
3339  * If the proclock list for this partition is empty, we can skip
3340  * acquiring the partition lock. This optimization is safer than the
3341  * situation in LockReleaseAll, because we got rid of any fast-path
3342  * locks during AtPrepare_Locks, so there cannot be any case where
3343  * another backend is adding something to our lists now. For safety,
3344  * though, we code this the same way as in LockReleaseAll.
3345  */
3346  if (SHMQueueNext(procLocks, procLocks,
3347  offsetof(PROCLOCK, procLink)) == NULL)
3348  continue; /* needn't examine this partition */
3349 
3350  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
3351 
3352  for (proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
3353  offsetof(PROCLOCK, procLink));
3354  proclock;
3355  proclock = nextplock)
3356  {
3357  /* Get link first, since we may unlink/relink this proclock */
3358  nextplock = (PROCLOCK *)
3359  SHMQueueNext(procLocks, &proclock->procLink,
3360  offsetof(PROCLOCK, procLink));
3361 
3362  Assert(proclock->tag.myProc == MyProc);
3363 
3364  lock = proclock->tag.myLock;
3365 
3366  /* Ignore VXID locks */
3368  continue;
3369 
3370  PROCLOCK_PRINT("PostPrepare_Locks", proclock);
3371  LOCK_PRINT("PostPrepare_Locks", lock, 0);
3372  Assert(lock->nRequested >= 0);
3373  Assert(lock->nGranted >= 0);
3374  Assert(lock->nGranted <= lock->nRequested);
3375  Assert((proclock->holdMask & ~lock->grantMask) == 0);
3376 
3377  /* Ignore it if nothing to release (must be a session lock) */
3378  if (proclock->releaseMask == 0)
3379  continue;
3380 
3381  /* Else we should be releasing all locks */
3382  if (proclock->releaseMask != proclock->holdMask)
3383  elog(PANIC, "we seem to have dropped a bit somewhere");
3384 
3385  /*
3386  * We cannot simply modify proclock->tag.myProc to reassign
3387  * ownership of the lock, because that's part of the hash key and
3388  * the proclock would then be in the wrong hash chain. Instead
3389  * use hash_update_hash_key. (We used to create a new hash entry,
3390  * but that risks out-of-memory failure if other processes are
3391  * busy making proclocks too.) We must unlink the proclock from
3392  * our procLink chain and put it into the new proc's chain, too.
3393  *
3394  * Note: the updated proclock hash key will still belong to the
3395  * same hash partition, cf proclock_hash(). So the partition lock
3396  * we already hold is sufficient for this.
3397  */
3398  SHMQueueDelete(&proclock->procLink);
3399 
3400  /*
3401  * Create the new hash key for the proclock.
3402  */
3403  proclocktag.myLock = lock;
3404  proclocktag.myProc = newproc;
3405 
3406  /*
3407  * Update groupLeader pointer to point to the new proc. (We'd
3408  * better not be a member of somebody else's lock group!)
3409  */
3410  Assert(proclock->groupLeader == proclock->tag.myProc);
3411  proclock->groupLeader = newproc;
3412 
3413  /*
3414  * Update the proclock. We should not find any existing entry for
3415  * the same hash key, since there can be only one entry for any
3416  * given lock with my own proc.
3417  */
3419  (void *) proclock,
3420  (void *) &proclocktag))
3421  elog(PANIC, "duplicate entry found while reassigning a prepared transaction's locks");
3422 
3423  /* Re-link into the new proc's proclock list */
3424  SHMQueueInsertBefore(&(newproc->myProcLocks[partition]),
3425  &proclock->procLink);
3426 
3427  PROCLOCK_PRINT("PostPrepare_Locks: updated", proclock);
3428  } /* loop over PROCLOCKs within this partition */
3429 
3430  LWLockRelease(partitionLock);
3431  } /* loop over partitions */
3432 
3433  END_CRIT_SECTION();
3434 }
PROCLOCKTAG tag
Definition: lock.h:351
Definition: lwlock.h:32
LOCALLOCKTAG tag
Definition: lock.h:408
static HTAB * LockMethodLocalHash
Definition: lock.c:255
int numLockOwners
Definition: lock.h:415
LOCKTAG lock
Definition: lock.h:389
LOCKMODE mode
Definition: lock.h:390
PROCLOCK * proclock
Definition: lock.h:413
int nRequested
Definition: lock.h:299
PGPROC * MyProc
Definition: proc.c:68
LOCKMASK holdMask
Definition: lock.h:355
LOCKTAG tag
Definition: lock.h:291
#define END_CRIT_SECTION()
Definition: miscadmin.h:134
#define START_CRIT_SECTION()
Definition: miscadmin.h:132
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Definition: elog.c:570
void SHMQueueInsertBefore(SHM_QUEUE *queue, SHM_QUEUE *elem)
Definition: shmqueue.c:89
static HTAB * LockMethodProcLockHash
Definition: lock.c:254
#define PANIC
Definition: elog.h:53
int nGranted
Definition: lock.h:301
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1726
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:506
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1296
Definition: lock.h:288
PGPROC * TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
Definition: twophase.c:879
#define ereport(elevel, rest)
Definition: elog.h:141
SHM_QUEUE procLink
Definition: lock.h:358
Pointer SHMQueueNext(const SHM_QUEUE *queue, const SHM_QUEUE *curElem, Size linkOffset)
Definition: shmqueue.c:145
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:337
uint8 locktag_type
Definition: lock.h:170
#define Assert(condition)
Definition: c.h:732
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1122
bool hash_update_hash_key(HTAB *hashp, void *existingEntry, const void *newKeyPtr)
Definition: dynahash.c:1115
LOCK * lock
Definition: lock.h:412
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1389
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1379
PGPROC * myProc
Definition: lock.h:345
#define LOCKBIT_ON(lockmode)
Definition: lock.h:87
LOCKMASK grantMask
Definition: lock.h:294
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
int errmsg(const char *fmt,...)
Definition: elog.c:784
#define elog(elevel,...)
Definition: elog.h:226
int i
Definition: