PostgreSQL Source Code  git master
lock.h File Reference
#include "lib/ilist.h"
#include "storage/backendid.h"
#include "storage/lockdefs.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#include "utils/timestamp.h"
Include dependency graph for lock.h:
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Data Structures

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)    (LocalTransactionIdIsValid((vxid).localTransactionId))
 
#define VirtualTransactionIdIsRecoveredPreparedXact(vxid)    ((vxid).backendId == InvalidBackendId)
 
#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_APPLY_TRANSACTION
 
#define SET_LOCKTAG_RELATION(locktag, dboid, reloid)
 
#define SET_LOCKTAG_RELATION_EXTEND(locktag, dboid, reloid)
 
#define SET_LOCKTAG_DATABASE_FROZEN_IDS(locktag, dboid)
 
#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 SET_LOCKTAG_APPLY_TRANSACTION(locktag, dboid, suboid, xid, objid)
 
#define LOCK_LOCKMETHOD(lock)   ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)
 
#define LOCK_LOCKTAG(lock)   ((LockTagType) (lock).tag.locktag_type)
 
#define PROCLOCK_LOCKMETHOD(proclock)    LOCK_LOCKMETHOD(*((proclock).tag.myLock))
 
#define LOCALLOCK_LOCKMETHOD(llock)   ((llock).tag.lock.locktag_lockmethodid)
 
#define LOCALLOCK_LOCKTAG(llock)   ((LockTagType) (llock).tag.lock.locktag_type)
 
#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 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_DATABASE_FROZEN_IDS , LOCKTAG_PAGE ,
  LOCKTAG_TUPLE , LOCKTAG_TRANSACTION , LOCKTAG_VIRTUALTRANSACTION , LOCKTAG_SPECULATIVE_TOKEN ,
  LOCKTAG_OBJECT , LOCKTAG_USERLOCK , LOCKTAG_ADVISORY , LOCKTAG_APPLY_TRANSACTION
}
 
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)
 
bool 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

PGDLLIMPORT int max_locks_per_xact
 
PGDLLIMPORT const char *const LockTagTypeNames []
 

Macro Definition Documentation

◆ DEFAULT_LOCKMETHOD

#define DEFAULT_LOCKMETHOD   1

Definition at line 125 of file lock.h.

◆ GET_VXID_FROM_PGPROC

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

Definition at line 77 of file lock.h.

◆ InvalidLocalTransactionId

#define InvalidLocalTransactionId   0

Definition at line 65 of file lock.h.

◆ LOCALLOCK_LOCKMETHOD

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

Definition at line 443 of file lock.h.

◆ LOCALLOCK_LOCKTAG

#define LOCALLOCK_LOCKTAG (   llock)    ((LockTagType) (llock).tag.lock.locktag_type)

Definition at line 444 of file lock.h.

◆ LocalTransactionIdIsValid

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

Definition at line 66 of file lock.h.

◆ LOCK_LOCKMETHOD

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

Definition at line 324 of file lock.h.

◆ LOCK_LOCKTAG

#define LOCK_LOCKTAG (   lock)    ((LockTagType) (lock).tag.locktag_type)

Definition at line 325 of file lock.h.

◆ LOCKBIT_OFF

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

Definition at line 85 of file lock.h.

◆ LOCKBIT_ON

#define LOCKBIT_ON (   lockmode)    (1 << (lockmode))

Definition at line 84 of file lock.h.

◆ LockHashPartition

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

Definition at line 525 of file lock.h.

◆ LockHashPartitionLock

#define LockHashPartitionLock (   hashcode)
Value:
LockHashPartition(hashcode)].lock)
LWLockPadded * MainLWLockArray
Definition: lwlock.c:212
#define LOCK_MANAGER_LWLOCK_OFFSET
Definition: lwlock.h:107
LWLock lock
Definition: lwlock.h:69

Definition at line 527 of file lock.h.

◆ LockHashPartitionLockByIndex

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

Definition at line 530 of file lock.h.

◆ LockHashPartitionLockByProc

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

Definition at line 542 of file lock.h.

◆ LOCKTAG_LAST_TYPE

#define LOCKTAG_LAST_TYPE   LOCKTAG_APPLY_TRANSACTION

Definition at line 152 of file lock.h.

◆ MAX_LOCKMODES

#define MAX_LOCKMODES   10

Definition at line 82 of file lock.h.

◆ PROCLOCK_LOCKMETHOD

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

Definition at line 382 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)
@ LOCKTAG_ADVISORY
Definition: lock.h:147
#define USER_LOCKMETHOD
Definition: lock.h:126

Definition at line 270 of file lock.h.

◆ SET_LOCKTAG_APPLY_TRANSACTION

#define SET_LOCKTAG_APPLY_TRANSACTION (   locktag,
  dboid,
  suboid,
  xid,
  objid 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (suboid), \
(locktag).locktag_field3 = (xid), \
(locktag).locktag_field4 = (objid), \
(locktag).locktag_type = LOCKTAG_APPLY_TRANSACTION, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
#define DEFAULT_LOCKMETHOD
Definition: lock.h:125
@ LOCKTAG_APPLY_TRANSACTION
Definition: lock.h:148

Definition at line 282 of file lock.h.

◆ SET_LOCKTAG_DATABASE_FROZEN_IDS

#define SET_LOCKTAG_DATABASE_FROZEN_IDS (   locktag,
  dboid 
)
Value:
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = 0, \
(locktag).locktag_field3 = 0, \
(locktag).locktag_field4 = 0, \
(locktag).locktag_type = LOCKTAG_DATABASE_FROZEN_IDS, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
@ LOCKTAG_DATABASE_FROZEN_IDS
Definition: lock.h:139

Definition at line 199 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)
@ LOCKTAG_OBJECT
Definition: lock.h:145

Definition at line 262 of file lock.h.

◆ 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)
@ LOCKTAG_PAGE
Definition: lock.h:140

Definition at line 208 of file lock.h.

◆ 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)
@ LOCKTAG_RELATION
Definition: lock.h:137

Definition at line 181 of file lock.h.

◆ 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)
@ LOCKTAG_RELATION_EXTEND
Definition: lock.h:138

Definition at line 190 of file lock.h.

◆ 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 token
Definition: indent_globs.h:126
@ LOCKTAG_SPECULATIVE_TOKEN
Definition: lock.h:144

Definition at line 247 of file lock.h.

◆ 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)
@ LOCKTAG_TRANSACTION
Definition: lock.h:142

Definition at line 226 of file lock.h.

◆ 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)
@ LOCKTAG_TUPLE
Definition: lock.h:141

Definition at line 217 of file lock.h.

◆ 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)
@ LOCKTAG_VIRTUALTRANSACTION
Definition: lock.h:143

Definition at line 235 of file lock.h.

◆ SetInvalidVirtualTransactionId

#define SetInvalidVirtualTransactionId (   vxid)
Value:
((vxid).backendId = InvalidBackendId, \
(vxid).localTransactionId = InvalidLocalTransactionId)
#define InvalidBackendId
Definition: backendid.h:23
#define InvalidLocalTransactionId
Definition: lock.h:65

Definition at line 74 of file lock.h.

◆ USER_LOCKMETHOD

#define USER_LOCKMETHOD   2

Definition at line 126 of file lock.h.

◆ VirtualTransactionIdEquals

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

Definition at line 71 of file lock.h.

◆ VirtualTransactionIdIsRecoveredPreparedXact

#define VirtualTransactionIdIsRecoveredPreparedXact (   vxid)     ((vxid).backendId == InvalidBackendId)

Definition at line 69 of file lock.h.

◆ VirtualTransactionIdIsValid

#define VirtualTransactionIdIsValid (   vxid)     (LocalTransactionIdIsValid((vxid).localTransactionId))

Definition at line 67 of file lock.h.

Typedef Documentation

◆ BlockedProcData

◆ BlockedProcsData

◆ LOCALLOCK

typedef struct LOCALLOCK LOCALLOCK

◆ LOCALLOCKOWNER

◆ LOCALLOCKTAG

typedef struct LOCALLOCKTAG LOCALLOCKTAG

◆ LOCK

typedef struct LOCK LOCK

◆ LockData

typedef struct LockData LockData

◆ LockInstanceData

◆ LockMethod

typedef const LockMethodData* LockMethod

Definition at line 116 of file lock.h.

◆ LockMethodData

◆ LOCKMETHODID

Definition at line 122 of file lock.h.

◆ LOCKTAG

typedef struct LOCKTAG LOCKTAG

◆ LockTagType

typedef enum LockTagType LockTagType

◆ PGPROC

typedef struct PGPROC PGPROC

Definition at line 1 of file lock.h.

◆ PROCLOCK

typedef struct PROCLOCK PROCLOCK

◆ PROCLOCKTAG

typedef struct PROCLOCKTAG 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 509 of file lock.h.

510 {
511  DS_NOT_YET_CHECKED, /* no deadlock check has run yet */
512  DS_NO_DEADLOCK, /* no deadlock detected */
513  DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */
514  DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */
515  DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum
516  * worker */
517 } DeadLockState;
DeadLockState
Definition: lock.h:510
@ DS_HARD_DEADLOCK
Definition: lock.h:514
@ DS_BLOCKED_BY_AUTOVACUUM
Definition: lock.h:515
@ DS_NO_DEADLOCK
Definition: lock.h:512
@ DS_NOT_YET_CHECKED
Definition: lock.h:511
@ DS_SOFT_DEADLOCK
Definition: lock.h:513

◆ LockAcquireResult

Enumerator
LOCKACQUIRE_NOT_AVAIL 
LOCKACQUIRE_OK 
LOCKACQUIRE_ALREADY_HELD 
LOCKACQUIRE_ALREADY_CLEAR 

Definition at line 500 of file lock.h.

501 {
502  LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */
503  LOCKACQUIRE_OK, /* lock successfully acquired */
504  LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */
505  LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */
LockAcquireResult
Definition: lock.h:501
@ LOCKACQUIRE_ALREADY_CLEAR
Definition: lock.h:505
@ LOCKACQUIRE_OK
Definition: lock.h:503
@ LOCKACQUIRE_ALREADY_HELD
Definition: lock.h:504
@ LOCKACQUIRE_NOT_AVAIL
Definition: lock.h:502

◆ LockTagType

Enumerator
LOCKTAG_RELATION 
LOCKTAG_RELATION_EXTEND 
LOCKTAG_DATABASE_FROZEN_IDS 
LOCKTAG_PAGE 
LOCKTAG_TUPLE 
LOCKTAG_TRANSACTION 
LOCKTAG_VIRTUALTRANSACTION 
LOCKTAG_SPECULATIVE_TOKEN 
LOCKTAG_OBJECT 
LOCKTAG_USERLOCK 
LOCKTAG_ADVISORY 
LOCKTAG_APPLY_TRANSACTION 

Definition at line 135 of file lock.h.

136 {
137  LOCKTAG_RELATION, /* whole relation */
138  LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */
139  LOCKTAG_DATABASE_FROZEN_IDS, /* pg_database.datfrozenxid */
140  LOCKTAG_PAGE, /* one page of a relation */
141  LOCKTAG_TUPLE, /* one physical tuple */
142  LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
143  LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
144  LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */
145  LOCKTAG_OBJECT, /* non-relation database object */
146  LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */
147  LOCKTAG_ADVISORY, /* advisory user locks */
148  LOCKTAG_APPLY_TRANSACTION /* transaction being applied on a logical
149  * replication subscriber */
150 } LockTagType;
LockTagType
Definition: lock.h:136
@ LOCKTAG_USERLOCK
Definition: lock.h:146

Function Documentation

◆ AbortStrongLockAcquire()

void AbortStrongLockAcquire ( void  )

Definition at line 1752 of file lock.c.

1753 {
1754  uint32 fasthashcode;
1755  LOCALLOCK *locallock = StrongLockInProgress;
1756 
1757  if (locallock == NULL)
1758  return;
1759 
1760  fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
1761  Assert(locallock->holdsStrongLockCount == true);
1763  Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
1764  FastPathStrongRelationLocks->count[fasthashcode]--;
1765  locallock->holdsStrongLockCount = false;
1766  StrongLockInProgress = NULL;
1768 }
unsigned int uint32
Definition: c.h:490
Assert(fmt[strlen(fmt) - 1] !='\n')
#define FastPathStrongLockHashPartition(hashcode)
Definition: lock.c:263
static volatile FastPathStrongRelationLockData * FastPathStrongRelationLocks
Definition: lock.c:272
static LOCALLOCK * StrongLockInProgress
Definition: lock.c:287
#define SpinLockRelease(lock)
Definition: spin.h:64
#define SpinLockAcquire(lock)
Definition: spin.h:62
uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]
Definition: lock.c:269
uint32 hashcode
Definition: lock.h:432
bool holdsStrongLockCount
Definition: lock.h:439

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

Referenced by LockAcquireExtended(), and LockErrorCleanup().

◆ AtPrepare_Locks()

void AtPrepare_Locks ( void  )

Definition at line 3279 of file lock.c.

3280 {
3281  HASH_SEQ_STATUS status;
3282  LOCALLOCK *locallock;
3283 
3284  /* First, verify there aren't locks of both xact and session level */
3286 
3287  /* Now do the per-locallock cleanup work */
3289 
3290  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3291  {
3292  TwoPhaseLockRecord record;
3293  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3294  bool haveSessionLock;
3295  bool haveXactLock;
3296  int i;
3297 
3298  /*
3299  * Ignore VXID locks. We don't want those to be held by prepared
3300  * transactions, since they aren't meaningful after a restart.
3301  */
3302  if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3303  continue;
3304 
3305  /* Ignore it if we don't actually hold the lock */
3306  if (locallock->nLocks <= 0)
3307  continue;
3308 
3309  /* Scan to see whether we hold it at session or transaction level */
3310  haveSessionLock = haveXactLock = false;
3311  for (i = locallock->numLockOwners - 1; i >= 0; i--)
3312  {
3313  if (lockOwners[i].owner == NULL)
3314  haveSessionLock = true;
3315  else
3316  haveXactLock = true;
3317  }
3318 
3319  /* Ignore it if we have only session lock */
3320  if (!haveXactLock)
3321  continue;
3322 
3323  /* This can't happen, because we already checked it */
3324  if (haveSessionLock)
3325  ereport(ERROR,
3326  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3327  errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3328 
3329  /*
3330  * If the local lock was taken via the fast-path, we need to move it
3331  * to the primary lock table, or just get a pointer to the existing
3332  * primary lock table entry if by chance it's already been
3333  * transferred.
3334  */
3335  if (locallock->proclock == NULL)
3336  {
3337  locallock->proclock = FastPathGetRelationLockEntry(locallock);
3338  locallock->lock = locallock->proclock->tag.myLock;
3339  }
3340 
3341  /*
3342  * Arrange to not release any strong lock count held by this lock
3343  * entry. We must retain the count until the prepared transaction is
3344  * committed or rolled back.
3345  */
3346  locallock->holdsStrongLockCount = false;
3347 
3348  /*
3349  * Create a 2PC record.
3350  */
3351  memcpy(&(record.locktag), &(locallock->tag.lock), sizeof(LOCKTAG));
3352  record.lockmode = locallock->tag.mode;
3353 
3355  &record, sizeof(TwoPhaseLockRecord));
3356  }
3357 }
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1431
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1421
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
int i
Definition: isn.c:73
static PROCLOCK * FastPathGetRelationLockEntry(LOCALLOCK *locallock)
Definition: lock.c:2775
static HTAB * LockMethodLocalHash
Definition: lock.c:283
static void CheckForSessionAndXactLocks(void)
Definition: lock.c:3191
LOCKTAG lock
Definition: lock.h:410
LOCKMODE mode
Definition: lock.h:411
LOCALLOCKOWNER * lockOwners
Definition: lock.h:438
LOCK * lock
Definition: lock.h:433
int64 nLocks
Definition: lock.h:435
int numLockOwners
Definition: lock.h:436
PROCLOCK * proclock
Definition: lock.h:434
LOCALLOCKTAG tag
Definition: lock.h:429
Definition: lock.h:165
uint8 locktag_type
Definition: lock.h:170
LOCK * myLock
Definition: lock.h:365
PROCLOCKTAG tag
Definition: lock.h:372
LOCKTAG locktag
Definition: lock.c:161
LOCKMODE lockmode
Definition: lock.c:162
void RegisterTwoPhaseRecord(TwoPhaseRmgrId rmid, uint16 info, const void *data, uint32 len)
Definition: twophase.c:1257
#define TWOPHASE_RM_LOCK_ID
Definition: twophase_rmgr.h:25

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

Referenced by PrepareTransaction().

◆ DeadLockCheck()

DeadLockState DeadLockCheck ( PGPROC proc)

Definition at line 217 of file deadlock.c.

218 {
219  /* Initialize to "no constraints" */
220  nCurConstraints = 0;
222  nWaitOrders = 0;
223 
224  /* Initialize to not blocked by an autovacuum worker */
226 
227  /* Search for deadlocks and possible fixes */
228  if (DeadLockCheckRecurse(proc))
229  {
230  /*
231  * Call FindLockCycle one more time, to record the correct
232  * deadlockDetails[] for the basic state with no rearrangements.
233  */
234  int nSoftEdges;
235 
236  TRACE_POSTGRESQL_DEADLOCK_FOUND();
237 
238  nWaitOrders = 0;
239  if (!FindLockCycle(proc, possibleConstraints, &nSoftEdges))
240  elog(FATAL, "deadlock seems to have disappeared");
241 
242  return DS_HARD_DEADLOCK; /* cannot find a non-deadlocked state */
243  }
244 
245  /* Apply any needed rearrangements of wait queues */
246  for (int i = 0; i < nWaitOrders; i++)
247  {
248  LOCK *lock = waitOrders[i].lock;
249  PGPROC **procs = waitOrders[i].procs;
250  int nProcs = waitOrders[i].nProcs;
251  dclist_head *waitQueue = &lock->waitProcs;
252 
253  Assert(nProcs == dclist_count(waitQueue));
254 
255 #ifdef DEBUG_DEADLOCK
256  PrintLockQueue(lock, "DeadLockCheck:");
257 #endif
258 
259  /* Reset the queue and re-add procs in the desired order */
260  dclist_init(waitQueue);
261  for (int j = 0; j < nProcs; j++)
262  dclist_push_tail(waitQueue, &procs[j]->links);
263 
264 #ifdef DEBUG_DEADLOCK
265  PrintLockQueue(lock, "rearranged to:");
266 #endif
267 
268  /* See if any waiters for the lock can be woken up now */
269  ProcLockWakeup(GetLocksMethodTable(lock), lock);
270  }
271 
272  /* Return code tells caller if we had to escape a deadlock or not */
273  if (nWaitOrders > 0)
274  return DS_SOFT_DEADLOCK;
275  else if (blocking_autovacuum_proc != NULL)
277  else
278  return DS_NO_DEADLOCK;
279 }
static WAIT_ORDER * waitOrders
Definition: deadlock.c:111
static bool FindLockCycle(PGPROC *checkProc, EDGE *softEdges, int *nSoftEdges)
Definition: deadlock.c:443
static bool DeadLockCheckRecurse(PGPROC *proc)
Definition: deadlock.c:309
static EDGE * possibleConstraints
Definition: deadlock.c:121
static int nWaitOrders
Definition: deadlock.c:112
static int nCurConstraints
Definition: deadlock.c:117
static PGPROC * blocking_autovacuum_proc
Definition: deadlock.c:128
static int nPossibleConstraints
Definition: deadlock.c:122
#define FATAL
Definition: elog.h:41
static void dclist_push_tail(dclist_head *head, dlist_node *node)
Definition: ilist.h:709
static uint32 dclist_count(const dclist_head *head)
Definition: ilist.h:932
static void dclist_init(dclist_head *head)
Definition: ilist.h:671
int j
Definition: isn.c:74
LockMethod GetLocksMethodTable(const LOCK *lock)
Definition: lock.c:487
void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock)
Definition: proc.c:1637
Definition: lock.h:309
dclist_head waitProcs
Definition: lock.h:317
Definition: proc.h:162
PGPROC ** procs
Definition: deadlock.c:59
LOCK * lock
Definition: deadlock.c:58
int nProcs
Definition: deadlock.c:60
static struct link * links
Definition: zic.c:299

References Assert(), blocking_autovacuum_proc, dclist_count(), dclist_init(), dclist_push_tail(), DeadLockCheckRecurse(), DS_BLOCKED_BY_AUTOVACUUM, DS_HARD_DEADLOCK, DS_NO_DEADLOCK, DS_SOFT_DEADLOCK, elog(), FATAL, FindLockCycle(), GetLocksMethodTable(), i, j, links, WAIT_ORDER::lock, nCurConstraints, nPossibleConstraints, WAIT_ORDER::nProcs, nWaitOrders, possibleConstraints, ProcLockWakeup(), WAIT_ORDER::procs, waitOrders, and LOCK::waitProcs.

Referenced by CheckDeadLock().

◆ DeadLockReport()

void DeadLockReport ( void  )

Definition at line 1073 of file deadlock.c.

1074 {
1075  StringInfoData clientbuf; /* errdetail for client */
1076  StringInfoData logbuf; /* errdetail for server log */
1077  StringInfoData locktagbuf;
1078  int i;
1079 
1080  initStringInfo(&clientbuf);
1081  initStringInfo(&logbuf);
1082  initStringInfo(&locktagbuf);
1083 
1084  /* Generate the "waits for" lines sent to the client */
1085  for (i = 0; i < nDeadlockDetails; i++)
1086  {
1087  DEADLOCK_INFO *info = &deadlockDetails[i];
1088  int nextpid;
1089 
1090  /* The last proc waits for the first one... */
1091  if (i < nDeadlockDetails - 1)
1092  nextpid = info[1].pid;
1093  else
1094  nextpid = deadlockDetails[0].pid;
1095 
1096  /* reset locktagbuf to hold next object description */
1097  resetStringInfo(&locktagbuf);
1098 
1099  DescribeLockTag(&locktagbuf, &info->locktag);
1100 
1101  if (i > 0)
1102  appendStringInfoChar(&clientbuf, '\n');
1103 
1104  appendStringInfo(&clientbuf,
1105  _("Process %d waits for %s on %s; blocked by process %d."),
1106  info->pid,
1108  info->lockmode),
1109  locktagbuf.data,
1110  nextpid);
1111  }
1112 
1113  /* Duplicate all the above for the server ... */
1114  appendBinaryStringInfo(&logbuf, clientbuf.data, clientbuf.len);
1115 
1116  /* ... and add info about query strings */
1117  for (i = 0; i < nDeadlockDetails; i++)
1118  {
1119  DEADLOCK_INFO *info = &deadlockDetails[i];
1120 
1121  appendStringInfoChar(&logbuf, '\n');
1122 
1123  appendStringInfo(&logbuf,
1124  _("Process %d: %s"),
1125  info->pid,
1127  }
1128 
1130 
1131  ereport(ERROR,
1133  errmsg("deadlock detected"),
1134  errdetail_internal("%s", clientbuf.data),
1135  errdetail_log("%s", logbuf.data),
1136  errhint("See server log for query details.")));
1137 }
const char * pgstat_get_backend_current_activity(int pid, bool checkUser)
static int nDeadlockDetails
Definition: deadlock.c:125
static DEADLOCK_INFO * deadlockDetails
Definition: deadlock.c:124
int errdetail_internal(const char *fmt,...)
Definition: elog.c:1229
int errhint(const char *fmt,...)
Definition: elog.c:1316
int errdetail_log(const char *fmt,...)
Definition: elog.c:1250
#define _(x)
Definition: elog.c:91
void DescribeLockTag(StringInfo buf, const LOCKTAG *tag)
Definition: lmgr.c:1168
const char * GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
Definition: lock.c:4045
#define ERRCODE_T_R_DEADLOCK_DETECTED
Definition: pgbench.c:77
void pgstat_report_deadlock(void)
void resetStringInfo(StringInfo str)
Definition: stringinfo.c:75
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:91
void appendBinaryStringInfo(StringInfo str, const void *data, int datalen)
Definition: stringinfo.c:227
void appendStringInfoChar(StringInfo str, char ch)
Definition: stringinfo.c:188
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59
LOCKTAG locktag
Definition: deadlock.c:73
LOCKMODE lockmode
Definition: deadlock.c:74
uint8 locktag_lockmethodid
Definition: lock.h:171

References _, appendBinaryStringInfo(), appendStringInfo(), appendStringInfoChar(), StringInfoData::data, deadlockDetails, DescribeLockTag(), ereport, errcode(), ERRCODE_T_R_DEADLOCK_DETECTED, 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().

◆ DoLockModesConflict()

bool DoLockModesConflict ( LOCKMODE  mode1,
LOCKMODE  mode2 
)

Definition at line 583 of file lock.c.

584 {
585  LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
586 
587  if (lockMethodTable->conflictTab[mode1] & LOCKBIT_ON(mode2))
588  return true;
589 
590  return false;
591 }
static const LockMethod LockMethods[]
Definition: lock.c:151
#define LOCKBIT_ON(lockmode)
Definition: lock.h:84
const LOCKMASK * conflictTab
Definition: lock.h:111

References LockMethodData::conflictTab, DEFAULT_LOCKMETHOD, LOCKBIT_ON, and LockMethods.

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

◆ GetBlockerStatusData()

BlockedProcsData* GetBlockerStatusData ( int  blocked_pid)

Definition at line 3788 of file lock.c.

3789 {
3791  PGPROC *proc;
3792  int i;
3793 
3795 
3796  /*
3797  * Guess how much space we'll need, and preallocate. Most of the time
3798  * this will avoid needing to do repalloc while holding the LWLocks. (We
3799  * assume, but check with an Assert, that MaxBackends is enough entries
3800  * for the procs[] array; the other two could need enlargement, though.)
3801  */
3802  data->nprocs = data->nlocks = data->npids = 0;
3803  data->maxprocs = data->maxlocks = data->maxpids = MaxBackends;
3804  data->procs = (BlockedProcData *) palloc(sizeof(BlockedProcData) * data->maxprocs);
3805  data->locks = (LockInstanceData *) palloc(sizeof(LockInstanceData) * data->maxlocks);
3806  data->waiter_pids = (int *) palloc(sizeof(int) * data->maxpids);
3807 
3808  /*
3809  * In order to search the ProcArray for blocked_pid and assume that that
3810  * entry won't immediately disappear under us, we must hold ProcArrayLock.
3811  * In addition, to examine the lock grouping fields of any other backend,
3812  * we must hold all the hash partition locks. (Only one of those locks is
3813  * actually relevant for any one lock group, but we can't know which one
3814  * ahead of time.) It's fairly annoying to hold all those locks
3815  * throughout this, but it's no worse than GetLockStatusData(), and it
3816  * does have the advantage that we're guaranteed to return a
3817  * self-consistent instantaneous state.
3818  */
3819  LWLockAcquire(ProcArrayLock, LW_SHARED);
3820 
3821  proc = BackendPidGetProcWithLock(blocked_pid);
3822 
3823  /* Nothing to do if it's gone */
3824  if (proc != NULL)
3825  {
3826  /*
3827  * Acquire lock on the entire shared lock data structure. See notes
3828  * in GetLockStatusData().
3829  */
3830  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3832 
3833  if (proc->lockGroupLeader == NULL)
3834  {
3835  /* Easy case, proc is not a lock group member */
3837  }
3838  else
3839  {
3840  /* Examine all procs in proc's lock group */
3841  dlist_iter iter;
3842 
3844  {
3845  PGPROC *memberProc;
3846 
3847  memberProc = dlist_container(PGPROC, lockGroupLink, iter.cur);
3848  GetSingleProcBlockerStatusData(memberProc, data);
3849  }
3850  }
3851 
3852  /*
3853  * And release locks. See notes in GetLockStatusData().
3854  */
3855  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
3857 
3858  Assert(data->nprocs <= data->maxprocs);
3859  }
3860 
3861  LWLockRelease(ProcArrayLock);
3862 
3863  return data;
3864 }
int MaxBackends
Definition: globals.c:140
#define dlist_foreach(iter, lhead)
Definition: ilist.h:623
#define dlist_container(type, membername, ptr)
Definition: ilist.h:593
static void GetSingleProcBlockerStatusData(PGPROC *blocked_proc, BlockedProcsData *data)
Definition: lock.c:3868
#define LockHashPartitionLockByIndex(i)
Definition: lock.h:530
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1195
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1803
#define NUM_LOCK_PARTITIONS
Definition: lwlock.h:99
@ LW_SHARED
Definition: lwlock.h:117
void * palloc(Size size)
Definition: mcxt.c:1226
const void * data
PGPROC * BackendPidGetProcWithLock(int pid)
Definition: procarray.c:3157
dlist_head lockGroupMembers
Definition: proc.h:296
PGPROC * lockGroupLeader
Definition: proc.h:295
dlist_node * cur
Definition: ilist.h:179

References Assert(), BackendPidGetProcWithLock(), dlist_iter::cur, data, dlist_container, dlist_foreach, GetSingleProcBlockerStatusData(), i, PGPROC::lockGroupLeader, PGPROC::lockGroupMembers, LockHashPartitionLockByIndex, LW_SHARED, LWLockAcquire(), LWLockRelease(), MaxBackends, NUM_LOCK_PARTITIONS, and palloc().

Referenced by pg_blocking_pids().

◆ GetBlockingAutoVacuumPgproc()

PGPROC* GetBlockingAutoVacuumPgproc ( void  )

Definition at line 287 of file deadlock.c.

288 {
289  PGPROC *ptr;
290 
293 
294  return ptr;
295 }

References blocking_autovacuum_proc.

Referenced by ProcSleep().

◆ GetLockConflicts()

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

Definition at line 2879 of file lock.c.

2880 {
2881  static VirtualTransactionId *vxids;
2882  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
2883  LockMethod lockMethodTable;
2884  LOCK *lock;
2885  LOCKMASK conflictMask;
2886  dlist_iter proclock_iter;
2887  PROCLOCK *proclock;
2888  uint32 hashcode;
2889  LWLock *partitionLock;
2890  int count = 0;
2891  int fast_count = 0;
2892 
2893  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2894  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2895  lockMethodTable = LockMethods[lockmethodid];
2896  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
2897  elog(ERROR, "unrecognized lock mode: %d", lockmode);
2898 
2899  /*
2900  * Allocate memory to store results, and fill with InvalidVXID. We only
2901  * need enough space for MaxBackends + max_prepared_xacts + a terminator.
2902  * InHotStandby allocate once in TopMemoryContext.
2903  */
2904  if (InHotStandby)
2905  {
2906  if (vxids == NULL)
2907  vxids = (VirtualTransactionId *)
2909  sizeof(VirtualTransactionId) *
2911  }
2912  else
2913  vxids = (VirtualTransactionId *)
2914  palloc0(sizeof(VirtualTransactionId) *
2916 
2917  /* Compute hash code and partition lock, and look up conflicting modes. */
2918  hashcode = LockTagHashCode(locktag);
2919  partitionLock = LockHashPartitionLock(hashcode);
2920  conflictMask = lockMethodTable->conflictTab[lockmode];
2921 
2922  /*
2923  * Fast path locks might not have been entered in the primary lock table.
2924  * If the lock we're dealing with could conflict with such a lock, we must
2925  * examine each backend's fast-path array for conflicts.
2926  */
2927  if (ConflictsWithRelationFastPath(locktag, lockmode))
2928  {
2929  int i;
2930  Oid relid = locktag->locktag_field2;
2931  VirtualTransactionId vxid;
2932 
2933  /*
2934  * Iterate over relevant PGPROCs. Anything held by a prepared
2935  * transaction will have been transferred to the primary lock table,
2936  * so we need not worry about those. This is all a bit fuzzy, because
2937  * new locks could be taken after we've visited a particular
2938  * partition, but the callers had better be prepared to deal with that
2939  * anyway, since the locks could equally well be taken between the
2940  * time we return the value and the time the caller does something
2941  * with it.
2942  */
2943  for (i = 0; i < ProcGlobal->allProcCount; i++)
2944  {
2945  PGPROC *proc = &ProcGlobal->allProcs[i];
2946  uint32 f;
2947 
2948  /* A backend never blocks itself */
2949  if (proc == MyProc)
2950  continue;
2951 
2953 
2954  /*
2955  * If the target backend isn't referencing the same database as
2956  * the lock, then we needn't examine the individual relation IDs
2957  * at all; none of them can be relevant.
2958  *
2959  * See FastPathTransferRelationLocks() for discussion of why we do
2960  * this test after acquiring the lock.
2961  */
2962  if (proc->databaseId != locktag->locktag_field1)
2963  {
2964  LWLockRelease(&proc->fpInfoLock);
2965  continue;
2966  }
2967 
2968  for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
2969  {
2970  uint32 lockmask;
2971 
2972  /* Look for an allocated slot matching the given relid. */
2973  if (relid != proc->fpRelId[f])
2974  continue;
2975  lockmask = FAST_PATH_GET_BITS(proc, f);
2976  if (!lockmask)
2977  continue;
2978  lockmask <<= FAST_PATH_LOCKNUMBER_OFFSET;
2979 
2980  /*
2981  * There can only be one entry per relation, so if we found it
2982  * and it doesn't conflict, we can skip the rest of the slots.
2983  */
2984  if ((lockmask & conflictMask) == 0)
2985  break;
2986 
2987  /* Conflict! */
2988  GET_VXID_FROM_PGPROC(vxid, *proc);
2989 
2990  if (VirtualTransactionIdIsValid(vxid))
2991  vxids[count++] = vxid;
2992  /* else, xact already committed or aborted */
2993 
2994  /* No need to examine remaining slots. */
2995  break;
2996  }
2997 
2998  LWLockRelease(&proc->fpInfoLock);
2999  }
3000  }
3001 
3002  /* Remember how many fast-path conflicts we found. */
3003  fast_count = count;
3004 
3005  /*
3006  * Look up the lock object matching the tag.
3007  */
3008  LWLockAcquire(partitionLock, LW_SHARED);
3009 
3011  locktag,
3012  hashcode,
3013  HASH_FIND,
3014  NULL);
3015  if (!lock)
3016  {
3017  /*
3018  * If the lock object doesn't exist, there is nothing holding a lock
3019  * on this lockable object.
3020  */
3021  LWLockRelease(partitionLock);
3022  vxids[count].backendId = InvalidBackendId;
3024  if (countp)
3025  *countp = count;
3026  return vxids;
3027  }
3028 
3029  /*
3030  * Examine each existing holder (or awaiter) of the lock.
3031  */
3032  dlist_foreach(proclock_iter, &lock->procLocks)
3033  {
3034  proclock = dlist_container(PROCLOCK, lockLink, proclock_iter.cur);
3035 
3036  if (conflictMask & proclock->holdMask)
3037  {
3038  PGPROC *proc = proclock->tag.myProc;
3039 
3040  /* A backend never blocks itself */
3041  if (proc != MyProc)
3042  {
3043  VirtualTransactionId vxid;
3044 
3045  GET_VXID_FROM_PGPROC(vxid, *proc);
3046 
3047  if (VirtualTransactionIdIsValid(vxid))
3048  {
3049  int i;
3050 
3051  /* Avoid duplicate entries. */
3052  for (i = 0; i < fast_count; ++i)
3053  if (VirtualTransactionIdEquals(vxids[i], vxid))
3054  break;
3055  if (i >= fast_count)
3056  vxids[count++] = vxid;
3057  }
3058  /* else, xact already committed or aborted */
3059  }
3060  }
3061  }
3062 
3063  LWLockRelease(partitionLock);
3064 
3065  if (count > MaxBackends + max_prepared_xacts) /* should never happen */
3066  elog(PANIC, "too many conflicting locks found");
3067 
3068  vxids[count].backendId = InvalidBackendId;
3070  if (countp)
3071  *countp = count;
3072  return vxids;
3073 }
#define lengthof(array)
Definition: c.h:772
void * hash_search_with_hash_value(HTAB *hashp, const void *keyPtr, uint32 hashvalue, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:966
#define PANIC
Definition: elog.h:42
@ HASH_FIND
Definition: hsearch.h:113
#define FAST_PATH_LOCKNUMBER_OFFSET
Definition: lock.c:203
#define ConflictsWithRelationFastPath(locktag, mode)
Definition: lock.c:233
static HTAB * LockMethodLockHash
Definition: lock.c:281
#define FAST_PATH_GET_BITS(proc, n)
Definition: lock.c:205
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:517
uint16 LOCKMETHODID
Definition: lock.h:122
#define VirtualTransactionIdIsValid(vxid)
Definition: lock.h:67
#define LockHashPartitionLock(hashcode)
Definition: lock.h:527
#define VirtualTransactionIdEquals(vxid1, vxid2)
Definition: lock.h:71
#define GET_VXID_FROM_PGPROC(vxid, proc)
Definition: lock.h:77
int LOCKMASK
Definition: lockdefs.h:25
MemoryContext TopMemoryContext
Definition: mcxt.c:141
void * palloc0(Size size)
Definition: mcxt.c:1257
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:1021
unsigned int Oid
Definition: postgres_ext.h:31
#define FP_LOCK_SLOTS_PER_BACKEND
Definition: proc.h:79
PGPROC * MyProc
Definition: proc.c:66
PROC_HDR * ProcGlobal
Definition: proc.c:78
uint32 locktag_field1
Definition: lock.h:166
uint32 locktag_field2
Definition: lock.h:167
dlist_head procLocks
Definition: lock.h:316
Definition: lwlock.h:41
int numLockModes
Definition: lock.h:110
LWLock fpInfoLock
Definition: proc.h:284
Oid fpRelId[FP_LOCK_SLOTS_PER_BACKEND]
Definition: proc.h:286
Oid databaseId
Definition: proc.h:198
PGPROC * myProc
Definition: lock.h:366
Definition: lock.h:370
LOCKMASK holdMask
Definition: lock.h:376
PGPROC * allProcs
Definition: proc.h:362
uint32 allProcCount
Definition: proc.h:380
LocalTransactionId localTransactionId
Definition: lock.h:62
BackendId backendId
Definition: lock.h:61
int max_prepared_xacts
Definition: twophase.c:117
#define InHotStandby
Definition: xlogutils.h:57

References PROC_HDR::allProcCount, PROC_HDR::allProcs, VirtualTransactionId::backendId, ConflictsWithRelationFastPath, LockMethodData::conflictTab, dlist_iter::cur, PGPROC::databaseId, dlist_container, dlist_foreach, elog(), ERROR, FAST_PATH_GET_BITS, FAST_PATH_LOCKNUMBER_OFFSET, FP_LOCK_SLOTS_PER_BACKEND, PGPROC::fpInfoLock, PGPROC::fpRelId, GET_VXID_FROM_PGPROC, HASH_FIND, hash_search_with_hash_value(), PROCLOCK::holdMask, i, InHotStandby, InvalidBackendId, InvalidLocalTransactionId, lengthof, VirtualTransactionId::localTransactionId, LockHashPartitionLock, LockMethodLockHash, LockMethods, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_SHARED, LWLockAcquire(), LWLockRelease(), max_prepared_xacts, MaxBackends, MemoryContextAlloc(), MyProc, PROCLOCKTAG::myProc, LockMethodData::numLockModes, palloc0(), PANIC, ProcGlobal, LOCK::procLocks, PROCLOCK::tag, TopMemoryContext, VirtualTransactionIdEquals, and VirtualTransactionIdIsValid.

Referenced by ProcSleep(), ResolveRecoveryConflictWithLock(), and WaitForLockersMultiple().

◆ GetLockmodeName()

const char* GetLockmodeName ( LOCKMETHODID  lockmethodid,
LOCKMODE  mode 
)

Definition at line 4045 of file lock.c.

4046 {
4047  Assert(lockmethodid > 0 && lockmethodid < lengthof(LockMethods));
4048  Assert(mode > 0 && mode <= LockMethods[lockmethodid]->numLockModes);
4049  return LockMethods[lockmethodid]->lockModeNames[mode];
4050 }
static PgChecksumMode mode
Definition: pg_checksums.c:65
const char *const * lockModeNames
Definition: lock.h:112

References Assert(), lengthof, LockMethods, LockMethodData::lockModeNames, and mode.

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

◆ GetLocksMethodTable()

LockMethod GetLocksMethodTable ( const LOCK lock)

Definition at line 487 of file lock.c.

488 {
489  LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*lock);
490 
491  Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
492  return LockMethods[lockmethodid];
493 }
#define LOCK_LOCKMETHOD(lock)
Definition: lock.h:324

References Assert(), lengthof, LOCK_LOCKMETHOD, and LockMethods.

Referenced by DeadLockCheck(), and FindLockCycleRecurseMember().

◆ GetLockStatusData()

LockData* GetLockStatusData ( void  )

Definition at line 3596 of file lock.c.

3597 {
3598  LockData *data;
3599  PROCLOCK *proclock;
3600  HASH_SEQ_STATUS seqstat;
3601  int els;
3602  int el;
3603  int i;
3604 
3605  data = (LockData *) palloc(sizeof(LockData));
3606 
3607  /* Guess how much space we'll need. */
3608  els = MaxBackends;
3609  el = 0;
3610  data->locks = (LockInstanceData *) palloc(sizeof(LockInstanceData) * els);
3611 
3612  /*
3613  * First, we iterate through the per-backend fast-path arrays, locking
3614  * them one at a time. This might produce an inconsistent picture of the
3615  * system state, but taking all of those LWLocks at the same time seems
3616  * impractical (in particular, note MAX_SIMUL_LWLOCKS). It shouldn't
3617  * matter too much, because none of these locks can be involved in lock
3618  * conflicts anyway - anything that might must be present in the main lock
3619  * table. (For the same reason, we don't sweat about making leaderPid
3620  * completely valid. We cannot safely dereference another backend's
3621  * lockGroupLeader field without holding all lock partition locks, and
3622  * it's not worth that.)
3623  */
3624  for (i = 0; i < ProcGlobal->allProcCount; ++i)
3625  {
3626  PGPROC *proc = &ProcGlobal->allProcs[i];
3627  uint32 f;
3628 
3630 
3631  for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; ++f)
3632  {
3633  LockInstanceData *instance;
3634  uint32 lockbits = FAST_PATH_GET_BITS(proc, f);
3635 
3636  /* Skip unallocated slots. */
3637  if (!lockbits)
3638  continue;
3639 
3640  if (el >= els)
3641  {
3642  els += MaxBackends;
3643  data->locks = (LockInstanceData *)
3644  repalloc(data->locks, sizeof(LockInstanceData) * els);
3645  }
3646 
3647  instance = &data->locks[el];
3648  SET_LOCKTAG_RELATION(instance->locktag, proc->databaseId,
3649  proc->fpRelId[f]);
3650  instance->holdMask = lockbits << FAST_PATH_LOCKNUMBER_OFFSET;
3651  instance->waitLockMode = NoLock;
3652  instance->backend = proc->backendId;
3653  instance->lxid = proc->lxid;
3654  instance->pid = proc->pid;
3655  instance->leaderPid = proc->pid;
3656  instance->fastpath = true;
3657 
3658  /*
3659  * Successfully taking fast path lock means there were no
3660  * conflicting locks.
3661  */
3662  instance->waitStart = 0;
3663 
3664  el++;
3665  }
3666 
3667  if (proc->fpVXIDLock)
3668  {
3669  VirtualTransactionId vxid;
3670  LockInstanceData *instance;
3671 
3672  if (el >= els)
3673  {
3674  els += MaxBackends;
3675  data->locks = (LockInstanceData *)
3676  repalloc(data->locks, sizeof(LockInstanceData) * els);
3677  }
3678 
3679  vxid.backendId = proc->backendId;
3681 
3682  instance = &data->locks[el];
3683  SET_LOCKTAG_VIRTUALTRANSACTION(instance->locktag, vxid);
3684  instance->holdMask = LOCKBIT_ON(ExclusiveLock);
3685  instance->waitLockMode = NoLock;
3686  instance->backend = proc->backendId;
3687  instance->lxid = proc->lxid;
3688  instance->pid = proc->pid;
3689  instance->leaderPid = proc->pid;
3690  instance->fastpath = true;
3691  instance->waitStart = 0;
3692 
3693  el++;
3694  }
3695 
3696  LWLockRelease(&proc->fpInfoLock);
3697  }
3698 
3699  /*
3700  * Next, acquire lock on the entire shared lock data structure. We do
3701  * this so that, at least for locks in the primary lock table, the state
3702  * will be self-consistent.
3703  *
3704  * Since this is a read-only operation, we take shared instead of
3705  * exclusive lock. There's not a whole lot of point to this, because all
3706  * the normal operations require exclusive lock, but it doesn't hurt
3707  * anything either. It will at least allow two backends to do
3708  * GetLockStatusData in parallel.
3709  *
3710  * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
3711  */
3712  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3714 
3715  /* Now we can safely count the number of proclocks */
3717  if (data->nelements > els)
3718  {
3719  els = data->nelements;
3720  data->locks = (LockInstanceData *)
3721  repalloc(data->locks, sizeof(LockInstanceData) * els);
3722  }
3723 
3724  /* Now scan the tables to copy the data */
3726 
3727  while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
3728  {
3729  PGPROC *proc = proclock->tag.myProc;
3730  LOCK *lock = proclock->tag.myLock;
3731  LockInstanceData *instance = &data->locks[el];
3732 
3733  memcpy(&instance->locktag, &lock->tag, sizeof(LOCKTAG));
3734  instance->holdMask = proclock->holdMask;
3735  if (proc->waitLock == proclock->tag.myLock)
3736  instance->waitLockMode = proc->waitLockMode;
3737  else
3738  instance->waitLockMode = NoLock;
3739  instance->backend = proc->backendId;
3740  instance->lxid = proc->lxid;
3741  instance->pid = proc->pid;
3742  instance->leaderPid = proclock->groupLeader->pid;
3743  instance->fastpath = false;
3744  instance->waitStart = (TimestampTz) pg_atomic_read_u64(&proc->waitStart);
3745 
3746  el++;
3747  }
3748 
3749  /*
3750  * And release locks. We do this in reverse order for two reasons: (1)
3751  * Anyone else who needs more than one of the locks will be trying to lock
3752  * them in increasing order; we don't want to release the other process
3753  * until it can get all the locks it needs. (2) This avoids O(N^2)
3754  * behavior inside LWLockRelease.
3755  */
3756  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
3758 
3759  Assert(el == data->nelements);
3760 
3761  return data;
3762 }
static uint64 pg_atomic_read_u64(volatile pg_atomic_uint64 *ptr)
Definition: atomics.h:424
int64 TimestampTz
Definition: timestamp.h:39
long hash_get_num_entries(HTAB *hashp)
Definition: dynahash.c:1377
static HTAB * LockMethodProcLockHash
Definition: lock.c:282
#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid)
Definition: lock.h:235
#define SET_LOCKTAG_RELATION(locktag, dboid, reloid)
Definition: lock.h:181
#define NoLock
Definition: lockdefs.h:34
#define ExclusiveLock
Definition: lockdefs.h:42
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1476
LOCKTAG tag
Definition: lock.h:311
Definition: lock.h:467
LOCKMASK holdMask
Definition: lock.h:455
LOCKMODE waitLockMode
Definition: lock.h:456
bool fastpath
Definition: lock.h:463
LOCKTAG locktag
Definition: lock.h:454
TimestampTz waitStart
Definition: lock.h:459
int leaderPid
Definition: lock.h:462
BackendId backend
Definition: lock.h:457
LocalTransactionId lxid
Definition: lock.h:458
LocalTransactionId lxid
Definition: proc.h:183
pg_atomic_uint64 waitStart
Definition: proc.h:228
bool fpVXIDLock
Definition: proc.h:287
BackendId backendId
Definition: proc.h:197
int pid
Definition: proc.h:186
LOCK * waitLock
Definition: proc.h:223
LOCKMODE waitLockMode
Definition: proc.h:225
LocalTransactionId fpLocalTransactionId
Definition: proc.h:288
PGPROC * groupLeader
Definition: lock.h:375

References PROC_HDR::allProcCount, PROC_HDR::allProcs, Assert(), LockInstanceData::backend, VirtualTransactionId::backendId, PGPROC::backendId, data, PGPROC::databaseId, ExclusiveLock, FAST_PATH_GET_BITS, FAST_PATH_LOCKNUMBER_OFFSET, LockInstanceData::fastpath, FP_LOCK_SLOTS_PER_BACKEND, PGPROC::fpInfoLock, 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, LockMethodProcLockHash, LockInstanceData::locktag, LW_SHARED, LWLockAcquire(), LWLockRelease(), LockInstanceData::lxid, PGPROC::lxid, MaxBackends, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, NoLock, NUM_LOCK_PARTITIONS, palloc(), pg_atomic_read_u64(), LockInstanceData::pid, PGPROC::pid, ProcGlobal, repalloc(), SET_LOCKTAG_RELATION, SET_LOCKTAG_VIRTUALTRANSACTION, LOCK::tag, PROCLOCK::tag, PGPROC::waitLock, LockInstanceData::waitLockMode, PGPROC::waitLockMode, LockInstanceData::waitStart, and PGPROC::waitStart.

Referenced by pg_lock_status().

◆ GetLockTagsMethodTable()

LockMethod GetLockTagsMethodTable ( const LOCKTAG locktag)

Definition at line 499 of file lock.c.

500 {
501  LOCKMETHODID lockmethodid = (LOCKMETHODID) locktag->locktag_lockmethodid;
502 
503  Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
504  return LockMethods[lockmethodid];
505 }

References Assert(), lengthof, LockMethods, and LOCKTAG::locktag_lockmethodid.

Referenced by pg_blocking_pids().

◆ GetRunningTransactionLocks()

xl_standby_lock* GetRunningTransactionLocks ( int *  nlocks)

Definition at line 3963 of file lock.c.

3964 {
3965  xl_standby_lock *accessExclusiveLocks;
3966  PROCLOCK *proclock;
3967  HASH_SEQ_STATUS seqstat;
3968  int i;
3969  int index;
3970  int els;
3971 
3972  /*
3973  * Acquire lock on the entire shared lock data structure.
3974  *
3975  * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
3976  */
3977  for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
3979 
3980  /* Now we can safely count the number of proclocks */
3982 
3983  /*
3984  * Allocating enough space for all locks in the lock table is overkill,
3985  * but it's more convenient and faster than having to enlarge the array.
3986  */
3987  accessExclusiveLocks = palloc(els * sizeof(xl_standby_lock));
3988 
3989  /* Now scan the tables to copy the data */
3991 
3992  /*
3993  * If lock is a currently granted AccessExclusiveLock then it will have
3994  * just one proclock holder, so locks are never accessed twice in this
3995  * particular case. Don't copy this code for use elsewhere because in the
3996  * general case this will give you duplicate locks when looking at
3997  * non-exclusive lock types.
3998  */
3999  index = 0;
4000  while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
4001  {
4002  /* make sure this definition matches the one used in LockAcquire */
4003  if ((proclock->holdMask & LOCKBIT_ON(AccessExclusiveLock)) &&
4004  proclock->tag.myLock->tag.locktag_type == LOCKTAG_RELATION)
4005  {
4006  PGPROC *proc = proclock->tag.myProc;
4007  LOCK *lock = proclock->tag.myLock;
4008  TransactionId xid = proc->xid;
4009 
4010  /*
4011  * Don't record locks for transactions if we know they have
4012  * already issued their WAL record for commit but not yet released
4013  * lock. It is still possible that we see locks held by already
4014  * complete transactions, if they haven't yet zeroed their xids.
4015  */
4016  if (!TransactionIdIsValid(xid))
4017  continue;
4018 
4019  accessExclusiveLocks[index].xid = xid;
4020  accessExclusiveLocks[index].dbOid = lock->tag.locktag_field1;
4021  accessExclusiveLocks[index].relOid = lock->tag.locktag_field2;
4022 
4023  index++;
4024  }
4025  }
4026 
4027  Assert(index <= els);
4028 
4029  /*
4030  * And release locks. We do this in reverse order for two reasons: (1)
4031  * Anyone else who needs more than one of the locks will be trying to lock
4032  * them in increasing order; we don't want to release the other process
4033  * until it can get all the locks it needs. (2) This avoids O(N^2)
4034  * behavior inside LWLockRelease.
4035  */
4036  for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
4038 
4039  *nlocks = index;
4040  return accessExclusiveLocks;
4041 }
uint32 TransactionId
Definition: c.h:636
#define AccessExclusiveLock
Definition: lockdefs.h:43
TransactionId xid
Definition: proc.h:173
Definition: type.h:95
TransactionId xid
Definition: lockdefs.h:51
#define TransactionIdIsValid(xid)
Definition: transam.h:41

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

Referenced by LogStandbySnapshot().

◆ GrantAwaitedLock()

void GrantAwaitedLock ( void  )

Definition at line 1781 of file lock.c.

1782 {
1784 }
static LOCALLOCK * awaitedLock
Definition: lock.c:288
static ResourceOwner awaitedOwner
Definition: lock.c:289
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner)
Definition: lock.c:1684

References awaitedLock, awaitedOwner, and GrantLockLocal().

Referenced by LockErrorCleanup(), and ProcSleep().

◆ GrantLock()

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

Definition at line 1550 of file lock.c.

1551 {
1552  lock->nGranted++;
1553  lock->granted[lockmode]++;
1554  lock->grantMask |= LOCKBIT_ON(lockmode);
1555  if (lock->granted[lockmode] == lock->requested[lockmode])
1556  lock->waitMask &= LOCKBIT_OFF(lockmode);
1557  proclock->holdMask |= LOCKBIT_ON(lockmode);
1558  LOCK_PRINT("GrantLock", lock, lockmode);
1559  Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
1560  Assert(lock->nGranted <= lock->nRequested);
1561 }
#define LOCK_PRINT(where, lock, type)
Definition: lock.c:365
#define LOCKBIT_OFF(lockmode)
Definition: lock.h:85
int nRequested
Definition: lock.h:319
int requested[MAX_LOCKMODES]
Definition: lock.h:318
int granted[MAX_LOCKMODES]
Definition: lock.h:320
LOCKMASK grantMask
Definition: lock.h:314
LOCKMASK waitMask
Definition: lock.h:315
int nGranted
Definition: lock.h:321

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

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

◆ InitDeadLockChecking()

void InitDeadLockChecking ( void  )

Definition at line 143 of file deadlock.c.

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 maxPossibleConstraints
Definition: deadlock.c:123
static PGPROC ** waitOrderProcs
Definition: deadlock.c:113
static PGPROC ** visitedProcs
Definition: deadlock.c:102
static int * beforeConstraints
Definition: deadlock.c:107
static int * afterConstraints
Definition: deadlock.c:108
static int maxCurConstraints
Definition: deadlock.c:118
static EDGE * curConstraints
Definition: deadlock.c:116
static PGPROC ** topoProcs
Definition: deadlock.c:106
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:138
Definition: deadlock.c:47

References afterConstraints, beforeConstraints, curConstraints, deadlockDetails, MaxBackends, maxCurConstraints, maxPossibleConstraints, MemoryContextSwitchTo(), palloc(), possibleConstraints, TopMemoryContext, topoProcs, visitedProcs, waitOrderProcs, and waitOrders.

Referenced by InitProcess().

◆ InitLocks()

void InitLocks ( void  )

Definition at line 405 of file lock.c.

406 {
407  HASHCTL info;
408  long init_table_size,
409  max_table_size;
410  bool found;
411 
412  /*
413  * Compute init/max size to request for lock hashtables. Note these
414  * calculations must agree with LockShmemSize!
415  */
416  max_table_size = NLOCKENTS();
417  init_table_size = max_table_size / 2;
418 
419  /*
420  * Allocate hash table for LOCK structs. This stores per-locked-object
421  * information.
422  */
423  info.keysize = sizeof(LOCKTAG);
424  info.entrysize = sizeof(LOCK);
426 
427  LockMethodLockHash = ShmemInitHash("LOCK hash",
428  init_table_size,
429  max_table_size,
430  &info,
432 
433  /* Assume an average of 2 holders per lock */
434  max_table_size *= 2;
435  init_table_size *= 2;
436 
437  /*
438  * Allocate hash table for PROCLOCK structs. This stores
439  * per-lock-per-holder information.
440  */
441  info.keysize = sizeof(PROCLOCKTAG);
442  info.entrysize = sizeof(PROCLOCK);
443  info.hash = proclock_hash;
445 
446  LockMethodProcLockHash = ShmemInitHash("PROCLOCK hash",
447  init_table_size,
448  max_table_size,
449  &info,
451 
452  /*
453  * Allocate fast-path structures.
454  */
456  ShmemInitStruct("Fast Path Strong Relation Lock Data",
457  sizeof(FastPathStrongRelationLockData), &found);
458  if (!found)
460 
461  /*
462  * Allocate non-shared hash table for LOCALLOCK structs. This stores lock
463  * counts and resource owner information.
464  *
465  * The non-shared table could already exist in this process (this occurs
466  * when the postmaster is recreating shared memory after a backend crash).
467  * If so, delete and recreate it. (We could simply leave it, since it
468  * ought to be empty in the postmaster, but for safety let's zap it.)
469  */
472 
473  info.keysize = sizeof(LOCALLOCKTAG);
474  info.entrysize = sizeof(LOCALLOCK);
475 
476  LockMethodLocalHash = hash_create("LOCALLOCK hash",
477  16,
478  &info,
480 }
void hash_destroy(HTAB *hashp)
Definition: dynahash.c:863
HTAB * hash_create(const char *tabname, long nelem, const HASHCTL *info, int flags)
Definition: dynahash.c:350
#define HASH_ELEM
Definition: hsearch.h:95
#define HASH_FUNCTION
Definition: hsearch.h:98
#define HASH_BLOBS
Definition: hsearch.h:97
#define HASH_PARTITION
Definition: hsearch.h:92
#define NLOCKENTS()
Definition: lock.c:57
static uint32 proclock_hash(const void *key, Size keysize)
Definition: lock.c:534
struct LOCALLOCK LOCALLOCK
struct LOCK LOCK
struct PROCLOCK PROCLOCK
struct LOCKTAG LOCKTAG
struct PROCLOCKTAG PROCLOCKTAG
struct LOCALLOCKTAG LOCALLOCKTAG
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:396
HTAB * ShmemInitHash(const char *name, long init_size, long max_size, HASHCTL *infoP, int hash_flags)
Definition: shmem.c:341
#define SpinLockInit(lock)
Definition: spin.h:60
Size keysize
Definition: hsearch.h:75
HashValueFunc hash
Definition: hsearch.h:78
Size entrysize
Definition: hsearch.h:76
long num_partitions
Definition: hsearch.h:68

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

Referenced by CreateSharedMemoryAndSemaphores().

◆ lock_twophase_postabort()

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

Definition at line 4388 of file lock.c.

4390 {
4391  lock_twophase_postcommit(xid, info, recdata, len);
4392 }
void lock_twophase_postcommit(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4362
const void size_t len

References len, and lock_twophase_postcommit().

◆ lock_twophase_postcommit()

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

Definition at line 4362 of file lock.c.

4364 {
4365  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4366  PGPROC *proc = TwoPhaseGetDummyProc(xid, true);
4367  LOCKTAG *locktag;
4368  LOCKMETHODID lockmethodid;
4369  LockMethod lockMethodTable;
4370 
4371  Assert(len == sizeof(TwoPhaseLockRecord));
4372  locktag = &rec->locktag;
4373  lockmethodid = locktag->locktag_lockmethodid;
4374 
4375  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4376  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4377  lockMethodTable = LockMethods[lockmethodid];
4378 
4379  LockRefindAndRelease(lockMethodTable, proc, locktag, rec->lockmode, true);
4380 }
static void LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, LOCKTAG *locktag, LOCKMODE lockmode, bool decrement_strong_lock_count)
Definition: lock.c:3087
PGPROC * TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
Definition: twophase.c:933

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

Referenced by lock_twophase_postabort().

◆ lock_twophase_recover()

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

Definition at line 4149 of file lock.c.

4151 {
4152  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4153  PGPROC *proc = TwoPhaseGetDummyProc(xid, false);
4154  LOCKTAG *locktag;
4155  LOCKMODE lockmode;
4156  LOCKMETHODID lockmethodid;
4157  LOCK *lock;
4158  PROCLOCK *proclock;
4159  PROCLOCKTAG proclocktag;
4160  bool found;
4161  uint32 hashcode;
4162  uint32 proclock_hashcode;
4163  int partition;
4164  LWLock *partitionLock;
4165  LockMethod lockMethodTable;
4166 
4167  Assert(len == sizeof(TwoPhaseLockRecord));
4168  locktag = &rec->locktag;
4169  lockmode = rec->lockmode;
4170  lockmethodid = locktag->locktag_lockmethodid;
4171 
4172  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4173  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4174  lockMethodTable = LockMethods[lockmethodid];
4175 
4176  hashcode = LockTagHashCode(locktag);
4177  partition = LockHashPartition(hashcode);
4178  partitionLock = LockHashPartitionLock(hashcode);
4179 
4180  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4181 
4182  /*
4183  * Find or create a lock with this tag.
4184  */
4186  locktag,
4187  hashcode,
4189  &found);
4190  if (!lock)
4191  {
4192  LWLockRelease(partitionLock);
4193  ereport(ERROR,
4194  (errcode(ERRCODE_OUT_OF_MEMORY),
4195  errmsg("out of shared memory"),
4196  errhint("You might need to increase max_locks_per_transaction.")));
4197  }
4198 
4199  /*
4200  * if it's a new lock object, initialize it
4201  */
4202  if (!found)
4203  {
4204  lock->grantMask = 0;
4205  lock->waitMask = 0;
4206  dlist_init(&lock->procLocks);
4207  dclist_init(&lock->waitProcs);
4208  lock->nRequested = 0;
4209  lock->nGranted = 0;
4210  MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
4211  MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
4212  LOCK_PRINT("lock_twophase_recover: new", lock, lockmode);
4213  }
4214  else
4215  {
4216  LOCK_PRINT("lock_twophase_recover: found", lock, lockmode);
4217  Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
4218  Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
4219  Assert(lock->nGranted <= lock->nRequested);
4220  }
4221 
4222  /*
4223  * Create the hash key for the proclock table.
4224  */
4225  proclocktag.myLock = lock;
4226  proclocktag.myProc = proc;
4227 
4228  proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
4229 
4230  /*
4231  * Find or create a proclock entry with this tag
4232  */
4234  &proclocktag,
4235  proclock_hashcode,
4237  &found);
4238  if (!proclock)
4239  {
4240  /* Oops, not enough shmem for the proclock */
4241  if (lock->nRequested == 0)
4242  {
4243  /*
4244  * There are no other requestors of this lock, so garbage-collect
4245  * the lock object. We *must* do this to avoid a permanent leak
4246  * of shared memory, because there won't be anything to cause
4247  * anyone to release the lock object later.
4248  */
4249  Assert(dlist_is_empty(&lock->procLocks));
4251  &(lock->tag),
4252  hashcode,
4253  HASH_REMOVE,
4254  NULL))
4255  elog(PANIC, "lock table corrupted");
4256  }
4257  LWLockRelease(partitionLock);
4258  ereport(ERROR,
4259  (errcode(ERRCODE_OUT_OF_MEMORY),
4260  errmsg("out of shared memory"),
4261  errhint("You might need to increase max_locks_per_transaction.")));
4262  }
4263 
4264  /*
4265  * If new, initialize the new entry
4266  */
4267  if (!found)
4268  {
4269  Assert(proc->lockGroupLeader == NULL);
4270  proclock->groupLeader = proc;
4271  proclock->holdMask = 0;
4272  proclock->releaseMask = 0;
4273  /* Add proclock to appropriate lists */
4274  dlist_push_tail(&lock->procLocks, &proclock->lockLink);
4275  dlist_push_tail(&proc->myProcLocks[partition],
4276  &proclock->procLink);
4277  PROCLOCK_PRINT("lock_twophase_recover: new", proclock);
4278  }
4279  else
4280  {
4281  PROCLOCK_PRINT("lock_twophase_recover: found", proclock);
4282  Assert((proclock->holdMask & ~lock->grantMask) == 0);
4283  }
4284 
4285  /*
4286  * lock->nRequested and lock->requested[] count the total number of
4287  * requests, whether granted or waiting, so increment those immediately.
4288  */
4289  lock->nRequested++;
4290  lock->requested[lockmode]++;
4291  Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
4292 
4293  /*
4294  * We shouldn't already hold the desired lock.
4295  */
4296  if (proclock->holdMask & LOCKBIT_ON(lockmode))
4297  elog(ERROR, "lock %s on object %u/%u/%u is already held",
4298  lockMethodTable->lockModeNames[lockmode],
4299  lock->tag.locktag_field1, lock->tag.locktag_field2,
4300  lock->tag.locktag_field3);
4301 
4302  /*
4303  * We ignore any possible conflicts and just grant ourselves the lock. Not
4304  * only because we don't bother, but also to avoid deadlocks when
4305  * switching from standby to normal mode. See function comment.
4306  */
4307  GrantLock(lock, proclock, lockmode);
4308 
4309  /*
4310  * Bump strong lock count, to make sure any fast-path lock requests won't
4311  * be granted without consulting the primary lock table.
4312  */
4313  if (ConflictsWithRelationFastPath(&lock->tag, lockmode))
4314  {
4315  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
4316 
4318  FastPathStrongRelationLocks->count[fasthashcode]++;
4320  }
4321 
4322  LWLockRelease(partitionLock);
4323 }
#define MemSet(start, val, len)
Definition: c.h:1004
@ HASH_REMOVE
Definition: hsearch.h:115
@ HASH_ENTER_NULL
Definition: hsearch.h:116
static void dlist_init(dlist_head *head)
Definition: ilist.h:314
static bool dlist_is_empty(const dlist_head *head)
Definition: ilist.h:336
static void dlist_push_tail(dlist_head *head, dlist_node *node)
Definition: ilist.h:364
static uint32 ProcLockHashCode(const PROCLOCKTAG *proclocktag, uint32 hashcode)
Definition: lock.c:565
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1550
#define PROCLOCK_PRINT(where, proclockP)
Definition: lock.c:366
#define MAX_LOCKMODES
Definition: lock.h:82
#define LockHashPartition(hashcode)
Definition: lock.h:525
int LOCKMODE
Definition: lockdefs.h:26
@ LW_EXCLUSIVE
Definition: lwlock.h:116
uint32 locktag_field3
Definition: lock.h:168
dlist_head myProcLocks[NUM_LOCK_PARTITIONS]
Definition: proc.h:252
dlist_node lockLink
Definition: lock.h:378
LOCKMASK releaseMask
Definition: lock.h:377
dlist_node procLink
Definition: lock.h:379

References Assert(), ConflictsWithRelationFastPath, FastPathStrongRelationLockData::count, dclist_init(), dlist_init(), dlist_is_empty(), dlist_push_tail(), elog(), ereport, errcode(), errhint(), errmsg(), ERROR, FastPathStrongLockHashPartition, FastPathStrongRelationLocks, LOCK::granted, GrantLock(), LOCK::grantMask, PROCLOCK::groupLeader, HASH_ENTER_NULL, HASH_REMOVE, hash_search_with_hash_value(), PROCLOCK::holdMask, len, lengthof, LOCK_PRINT, LOCKBIT_ON, PGPROC::lockGroupLeader, LockHashPartition, LockHashPartitionLock, PROCLOCK::lockLink, LockMethodLockHash, LockMethodProcLockHash, LockMethods, 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, PROCLOCK::releaseMask, LOCK::requested, SpinLockAcquire, SpinLockRelease, LOCK::tag, TwoPhaseGetDummyProc(), LOCK::waitMask, and LOCK::waitProcs.

◆ lock_twophase_standby_recover()

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

Definition at line 4330 of file lock.c.

4332 {
4333  TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4334  LOCKTAG *locktag;
4335  LOCKMODE lockmode;
4336  LOCKMETHODID lockmethodid;
4337 
4338  Assert(len == sizeof(TwoPhaseLockRecord));
4339  locktag = &rec->locktag;
4340  lockmode = rec->lockmode;
4341  lockmethodid = locktag->locktag_lockmethodid;
4342 
4343  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4344  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4345 
4346  if (lockmode == AccessExclusiveLock &&
4347  locktag->locktag_type == LOCKTAG_RELATION)
4348  {
4350  locktag->locktag_field1 /* dboid */ ,
4351  locktag->locktag_field2 /* reloid */ );
4352  }
4353 }
void StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid)
Definition: standby.c:986

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

◆ LockAcquire()

LockAcquireResult LockAcquire ( const LOCKTAG locktag,
LOCKMODE  lockmode,
bool  sessionLock,
bool  dontWait 
)

◆ LockAcquireExtended()

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

Definition at line 771 of file lock.c.

777 {
778  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
779  LockMethod lockMethodTable;
780  LOCALLOCKTAG localtag;
781  LOCALLOCK *locallock;
782  LOCK *lock;
783  PROCLOCK *proclock;
784  bool found;
785  ResourceOwner owner;
786  uint32 hashcode;
787  LWLock *partitionLock;
788  bool found_conflict;
789  bool log_lock = false;
790 
791  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
792  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
793  lockMethodTable = LockMethods[lockmethodid];
794  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
795  elog(ERROR, "unrecognized lock mode: %d", lockmode);
796 
797  if (RecoveryInProgress() && !InRecovery &&
798  (locktag->locktag_type == LOCKTAG_OBJECT ||
799  locktag->locktag_type == LOCKTAG_RELATION) &&
800  lockmode > RowExclusiveLock)
801  ereport(ERROR,
802  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
803  errmsg("cannot acquire lock mode %s on database objects while recovery is in progress",
804  lockMethodTable->lockModeNames[lockmode]),
805  errhint("Only RowExclusiveLock or less can be acquired on database objects during recovery.")));
806 
807 #ifdef LOCK_DEBUG
808  if (LOCK_DEBUG_ENABLED(locktag))
809  elog(LOG, "LockAcquire: lock [%u,%u] %s",
810  locktag->locktag_field1, locktag->locktag_field2,
811  lockMethodTable->lockModeNames[lockmode]);
812 #endif
813 
814  /* Identify owner for lock */
815  if (sessionLock)
816  owner = NULL;
817  else
818  owner = CurrentResourceOwner;
819 
820  /*
821  * Find or create a LOCALLOCK entry for this lock and lockmode
822  */
823  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
824  localtag.lock = *locktag;
825  localtag.mode = lockmode;
826 
827  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
828  &localtag,
829  HASH_ENTER, &found);
830 
831  /*
832  * if it's a new locallock object, initialize it
833  */
834  if (!found)
835  {
836  locallock->lock = NULL;
837  locallock->proclock = NULL;
838  locallock->hashcode = LockTagHashCode(&(localtag.lock));
839  locallock->nLocks = 0;
840  locallock->holdsStrongLockCount = false;
841  locallock->lockCleared = false;
842  locallock->numLockOwners = 0;
843  locallock->maxLockOwners = 8;
844  locallock->lockOwners = NULL; /* in case next line fails */
845  locallock->lockOwners = (LOCALLOCKOWNER *)
847  locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
848  }
849  else
850  {
851  /* Make sure there will be room to remember the lock */
852  if (locallock->numLockOwners >= locallock->maxLockOwners)
853  {
854  int newsize = locallock->maxLockOwners * 2;
855 
856  locallock->lockOwners = (LOCALLOCKOWNER *)
857  repalloc(locallock->lockOwners,
858  newsize * sizeof(LOCALLOCKOWNER));
859  locallock->maxLockOwners = newsize;
860  }
861  }
862  hashcode = locallock->hashcode;
863 
864  if (locallockp)
865  *locallockp = locallock;
866 
867  /*
868  * If we already hold the lock, we can just increase the count locally.
869  *
870  * If lockCleared is already set, caller need not worry about absorbing
871  * sinval messages related to the lock's object.
872  */
873  if (locallock->nLocks > 0)
874  {
875  GrantLockLocal(locallock, owner);
876  if (locallock->lockCleared)
878  else
880  }
881 
882  /*
883  * We don't acquire any other heavyweight lock while holding the relation
884  * extension lock. We do allow to acquire the same relation extension
885  * lock more than once but that case won't reach here.
886  */
887  Assert(!IsRelationExtensionLockHeld);
888 
889  /*
890  * We don't acquire any other heavyweight lock while holding the page lock
891  * except for relation extension.
892  */
893  Assert(!IsPageLockHeld ||
894  (locktag->locktag_type == LOCKTAG_RELATION_EXTEND));
895 
896  /*
897  * Prepare to emit a WAL record if acquisition of this lock needs to be
898  * replayed in a standby server.
899  *
900  * Here we prepare to log; after lock is acquired we'll issue log record.
901  * This arrangement simplifies error recovery in case the preparation step
902  * fails.
903  *
904  * Only AccessExclusiveLocks can conflict with lock types that read-only
905  * transactions can acquire in a standby server. Make sure this definition
906  * matches the one in GetRunningTransactionLocks().
907  */
908  if (lockmode >= AccessExclusiveLock &&
909  locktag->locktag_type == LOCKTAG_RELATION &&
910  !RecoveryInProgress() &&
912  {
914  log_lock = true;
915  }
916 
917  /*
918  * Attempt to take lock via fast path, if eligible. But if we remember
919  * having filled up the fast path array, we don't attempt to make any
920  * further use of it until we release some locks. It's possible that some
921  * other backend has transferred some of those locks to the shared hash
922  * table, leaving space free, but it's not worth acquiring the LWLock just
923  * to check. It's also possible that we're acquiring a second or third
924  * lock type on a relation we have already locked using the fast-path, but
925  * for now we don't worry about that case either.
926  */
927  if (EligibleForRelationFastPath(locktag, lockmode) &&
929  {
930  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
931  bool acquired;
932 
933  /*
934  * LWLockAcquire acts as a memory sequencing point, so it's safe to
935  * assume that any strong locker whose increment to
936  * FastPathStrongRelationLocks->counts becomes visible after we test
937  * it has yet to begin to transfer fast-path locks.
938  */
940  if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
941  acquired = false;
942  else
943  acquired = FastPathGrantRelationLock(locktag->locktag_field2,
944  lockmode);
946  if (acquired)
947  {
948  /*
949  * The locallock might contain stale pointers to some old shared
950  * objects; we MUST reset these to null before considering the
951  * lock to be acquired via fast-path.
952  */
953  locallock->lock = NULL;
954  locallock->proclock = NULL;
955  GrantLockLocal(locallock, owner);
956  return LOCKACQUIRE_OK;
957  }
958  }
959 
960  /*
961  * If this lock could potentially have been taken via the fast-path by
962  * some other backend, we must (temporarily) disable further use of the
963  * fast-path for this lock tag, and migrate any locks already taken via
964  * this method to the main lock table.
965  */
966  if (ConflictsWithRelationFastPath(locktag, lockmode))
967  {
968  uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
969 
970  BeginStrongLockAcquire(locallock, fasthashcode);
971  if (!FastPathTransferRelationLocks(lockMethodTable, locktag,
972  hashcode))
973  {
975  if (locallock->nLocks == 0)
976  RemoveLocalLock(locallock);
977  if (locallockp)
978  *locallockp = NULL;
979  if (reportMemoryError)
980  ereport(ERROR,
981  (errcode(ERRCODE_OUT_OF_MEMORY),
982  errmsg("out of shared memory"),
983  errhint("You might need to increase max_locks_per_transaction.")));
984  else
985  return LOCKACQUIRE_NOT_AVAIL;
986  }
987  }
988 
989  /*
990  * We didn't find the lock in our LOCALLOCK table, and we didn't manage to
991  * take it via the fast-path, either, so we've got to mess with the shared
992  * lock table.
993  */
994  partitionLock = LockHashPartitionLock(hashcode);
995 
996  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
997 
998  /*
999  * Find or create lock and proclock entries with this tag
1000  *
1001  * Note: if the locallock object already existed, it might have a pointer
1002  * to the lock already ... but we should not assume that that pointer is
1003  * valid, since a lock object with zero hold and request counts can go
1004  * away anytime. So we have to use SetupLockInTable() to recompute the
1005  * lock and proclock pointers, even if they're already set.
1006  */
1007  proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
1008  hashcode, lockmode);
1009  if (!proclock)
1010  {
1012  LWLockRelease(partitionLock);
1013  if (locallock->nLocks == 0)
1014  RemoveLocalLock(locallock);
1015  if (locallockp)
1016  *locallockp = NULL;
1017  if (reportMemoryError)
1018  ereport(ERROR,
1019  (errcode(ERRCODE_OUT_OF_MEMORY),
1020  errmsg("out of shared memory"),
1021  errhint("You might need to increase max_locks_per_transaction.")));
1022  else
1023  return LOCKACQUIRE_NOT_AVAIL;
1024  }
1025  locallock->proclock = proclock;
1026  lock = proclock->tag.myLock;
1027  locallock->lock = lock;
1028 
1029  /*
1030  * If lock requested conflicts with locks requested by waiters, must join
1031  * wait queue. Otherwise, check for conflict with already-held locks.
1032  * (That's last because most complex check.)
1033  */
1034  if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
1035  found_conflict = true;
1036  else
1037  found_conflict = LockCheckConflicts(lockMethodTable, lockmode,
1038  lock, proclock);
1039 
1040  if (!found_conflict)
1041  {
1042  /* No conflict with held or previously requested locks */
1043  GrantLock(lock, proclock, lockmode);
1044  GrantLockLocal(locallock, owner);
1045  }
1046  else
1047  {
1048  /*
1049  * We can't acquire the lock immediately. If caller specified no
1050  * blocking, remove useless table entries and return
1051  * LOCKACQUIRE_NOT_AVAIL without waiting.
1052  */
1053  if (dontWait)
1054  {
1056  if (proclock->holdMask == 0)
1057  {
1058  uint32 proclock_hashcode;
1059 
1060  proclock_hashcode = ProcLockHashCode(&proclock->tag, hashcode);
1061  dlist_delete(&proclock->lockLink);
1062  dlist_delete(&proclock->procLink);
1064  &(proclock->tag),
1065  proclock_hashcode,
1066  HASH_REMOVE,
1067  NULL))
1068  elog(PANIC, "proclock table corrupted");
1069  }
1070  else
1071  PROCLOCK_PRINT("LockAcquire: NOWAIT", proclock);
1072  lock->nRequested--;
1073  lock->requested[lockmode]--;
1074  LOCK_PRINT("LockAcquire: conditional lock failed", lock, lockmode);
1075  Assert((lock->nRequested > 0) && (lock->requested[lockmode] >= 0));
1076  Assert(lock->nGranted <= lock->nRequested);
1077  LWLockRelease(partitionLock);
1078  if (locallock->nLocks == 0)
1079  RemoveLocalLock(locallock);
1080  if (locallockp)
1081  *locallockp = NULL;
1082  return LOCKACQUIRE_NOT_AVAIL;
1083  }
1084 
1085  /*
1086  * Set bitmask of locks this process already holds on this object.
1087  */
1088  MyProc->heldLocks = proclock->holdMask;
1089 
1090  /*
1091  * Sleep till someone wakes me up.
1092  */
1093 
1094  TRACE_POSTGRESQL_LOCK_WAIT_START(locktag->locktag_field1,
1095  locktag->locktag_field2,
1096  locktag->locktag_field3,
1097  locktag->locktag_field4,
1098  locktag->locktag_type,
1099  lockmode);
1100 
1101  WaitOnLock(locallock, owner);
1102 
1103  TRACE_POSTGRESQL_LOCK_WAIT_DONE(locktag->locktag_field1,
1104  locktag->locktag_field2,
1105  locktag->locktag_field3,
1106  locktag->locktag_field4,
1107  locktag->locktag_type,
1108  lockmode);
1109 
1110  /*
1111  * NOTE: do not do any material change of state between here and
1112  * return. All required changes in locktable state must have been
1113  * done when the lock was granted to us --- see notes in WaitOnLock.
1114  */
1115 
1116  /*
1117  * Check the proclock entry status, in case something in the ipc
1118  * communication doesn't work correctly.
1119  */
1120  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
1121  {
1123  PROCLOCK_PRINT("LockAcquire: INCONSISTENT", proclock);
1124  LOCK_PRINT("LockAcquire: INCONSISTENT", lock, lockmode);
1125  /* Should we retry ? */
1126  LWLockRelease(partitionLock);
1127  elog(ERROR, "LockAcquire failed");
1128  }
1129  PROCLOCK_PRINT("LockAcquire: granted", proclock);
1130  LOCK_PRINT("LockAcquire: granted", lock, lockmode);
1131  }
1132 
1133  /*
1134  * Lock state is fully up-to-date now; if we error out after this, no
1135  * special error cleanup is required.
1136  */
1138 
1139  LWLockRelease(partitionLock);
1140 
1141  /*
1142  * Emit a WAL record if acquisition of this lock needs to be replayed in a
1143  * standby server.
1144  */
1145  if (log_lock)
1146  {
1147  /*
1148  * Decode the locktag back to the original values, to avoid sending
1149  * lots of empty bytes with every message. See lock.h to check how a
1150  * locktag is defined for LOCKTAG_RELATION
1151  */
1153  locktag->locktag_field2);
1154  }
1155 
1156  return LOCKACQUIRE_OK;
1157 }
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:953
#define LOG
Definition: elog.h:31
@ HASH_ENTER
Definition: hsearch.h:114
static void dlist_delete(dlist_node *node)
Definition: ilist.h:405
static void RemoveLocalLock(LOCALLOCK *locallock)
Definition: lock.c:1366
static PROCLOCK * SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc, const LOCKTAG *locktag, uint32 hashcode, LOCKMODE lockmode)
Definition: lock.c:1170
static bool FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag, uint32 hashcode)
Definition: lock.c:2687
void AbortStrongLockAcquire(void)
Definition: lock.c:1752
static bool FastPathGrantRelationLock(Oid relid, LOCKMODE lockmode)
Definition: lock.c:2620
static void WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
Definition: lock.c:1809
static int FastPathLocalUseCount
Definition: lock.c:172
#define EligibleForRelationFastPath(locktag, mode)
Definition: lock.c:227
static void BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
Definition: lock.c:1716
bool LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
Definition: lock.c:1419
static void FinishStrongLockAcquire(void)
Definition: lock.c:1742
#define RowExclusiveLock
Definition: lockdefs.h:38
ResourceOwner CurrentResourceOwner
Definition: resowner.c:147
void LogAccessExclusiveLockPrepare(void)
Definition: standby.c:1433
void LogAccessExclusiveLock(Oid dbOid, Oid relOid)
Definition: standby.c:1416
int maxLockOwners
Definition: lock.h:437
bool lockCleared
Definition: lock.h:440
uint16 locktag_field4
Definition: lock.h:169
LOCKMASK heldLocks
Definition: proc.h:226
bool RecoveryInProgress(void)
Definition: xlog.c:5921
#define XLogStandbyInfoActive()
Definition: xlog.h:118
bool InRecovery
Definition: xlogutils.c:53

References AbortStrongLockAcquire(), AccessExclusiveLock, Assert(), BeginStrongLockAcquire(), ConflictsWithRelationFastPath, LockMethodData::conflictTab, FastPathStrongRelationLockData::count, CurrentResourceOwner, dlist_delete(), EligibleForRelationFastPath, elog(), ereport, errcode(), errhint(), errmsg(), ERROR, FastPathGrantRelationLock(), FastPathLocalUseCount, FastPathStrongLockHashPartition, FastPathStrongRelationLocks, FastPathTransferRelationLocks(), FinishStrongLockAcquire(), FP_LOCK_SLOTS_PER_BACKEND, PGPROC::fpInfoLock, 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, LockMethodLocalHash, LockMethodProcLockHash, LockMethods, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_field4, LOCKTAG::locktag_lockmethodid, LOCKTAG_OBJECT, LOCKTAG_RELATION, LOCKTAG_RELATION_EXTEND, 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(), PROCLOCK::tag, TopMemoryContext, LOCK::waitMask, WaitOnLock(), and XLogStandbyInfoActive.

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

◆ LockCheckConflicts()

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

Definition at line 1419 of file lock.c.

1423 {
1424  int numLockModes = lockMethodTable->numLockModes;
1425  LOCKMASK myLocks;
1426  int conflictMask = lockMethodTable->conflictTab[lockmode];
1427  int conflictsRemaining[MAX_LOCKMODES];
1428  int totalConflictsRemaining = 0;
1429  dlist_iter proclock_iter;
1430  int i;
1431 
1432  /*
1433  * first check for global conflicts: If no locks conflict with my request,
1434  * then I get the lock.
1435  *
1436  * Checking for conflict: lock->grantMask represents the types of
1437  * currently held locks. conflictTable[lockmode] has a bit set for each
1438  * type of lock that conflicts with request. Bitwise compare tells if
1439  * there is a conflict.
1440  */
1441  if (!(conflictMask & lock->grantMask))
1442  {
1443  PROCLOCK_PRINT("LockCheckConflicts: no conflict", proclock);
1444  return false;
1445  }
1446 
1447  /*
1448  * Rats. Something conflicts. But it could still be my own lock, or a
1449  * lock held by another member of my locking group. First, figure out how
1450  * many conflicts remain after subtracting out any locks I hold myself.
1451  */
1452  myLocks = proclock->holdMask;
1453  for (i = 1; i <= numLockModes; i++)
1454  {
1455  if ((conflictMask & LOCKBIT_ON(i)) == 0)
1456  {
1457  conflictsRemaining[i] = 0;
1458  continue;
1459  }
1460  conflictsRemaining[i] = lock->granted[i];
1461  if (myLocks & LOCKBIT_ON(i))
1462  --conflictsRemaining[i];
1463  totalConflictsRemaining += conflictsRemaining[i];
1464  }
1465 
1466  /* If no conflicts remain, we get the lock. */
1467  if (totalConflictsRemaining == 0)
1468  {
1469  PROCLOCK_PRINT("LockCheckConflicts: resolved (simple)", proclock);
1470  return false;
1471  }
1472 
1473  /* If no group locking, it's definitely a conflict. */
1474  if (proclock->groupLeader == MyProc && MyProc->lockGroupLeader == NULL)
1475  {
1476  Assert(proclock->tag.myProc == MyProc);
1477  PROCLOCK_PRINT("LockCheckConflicts: conflicting (simple)",
1478  proclock);
1479  return true;
1480  }
1481 
1482  /*
1483  * The relation extension or page lock conflict even between the group
1484  * members.
1485  */
1486  if (LOCK_LOCKTAG(*lock) == LOCKTAG_RELATION_EXTEND ||
1487  (LOCK_LOCKTAG(*lock) == LOCKTAG_PAGE))
1488  {
1489  PROCLOCK_PRINT("LockCheckConflicts: conflicting (group)",
1490  proclock);
1491  return true;
1492  }
1493 
1494  /*
1495  * Locks held in conflicting modes by members of our own lock group are
1496  * not real conflicts; we can subtract those out and see if we still have
1497  * a conflict. This is O(N) in the number of processes holding or
1498  * awaiting locks on this object. We could improve that by making the
1499  * shared memory state more complex (and larger) but it doesn't seem worth
1500  * it.
1501  */
1502  dlist_foreach(proclock_iter, &lock->procLocks)
1503  {
1504  PROCLOCK *otherproclock =
1505  dlist_container(PROCLOCK, lockLink, proclock_iter.cur);
1506 
1507  if (proclock != otherproclock &&
1508  proclock->groupLeader == otherproclock->groupLeader &&
1509  (otherproclock->holdMask & conflictMask) != 0)
1510  {
1511  int intersectMask = otherproclock->holdMask & conflictMask;
1512 
1513  for (i = 1; i <= numLockModes; i++)
1514  {
1515  if ((intersectMask & LOCKBIT_ON(i)) != 0)
1516  {
1517  if (conflictsRemaining[i] <= 0)
1518  elog(PANIC, "proclocks held do not match lock");
1519  conflictsRemaining[i]--;
1520  totalConflictsRemaining--;
1521  }
1522  }
1523 
1524  if (totalConflictsRemaining == 0)
1525  {
1526  PROCLOCK_PRINT("LockCheckConflicts: resolved (group)",
1527  proclock);
1528  return false;
1529  }
1530  }
1531  }
1532 
1533  /* Nope, it's a real conflict. */
1534  PROCLOCK_PRINT("LockCheckConflicts: conflicting (group)", proclock);
1535  return true;
1536 }
#define LOCK_LOCKTAG(lock)
Definition: lock.h:325

References Assert(), LockMethodData::conflictTab, dlist_iter::cur, dlist_container, dlist_foreach, elog(), LOCK::granted, LOCK::grantMask, PROCLOCK::groupLeader, PROCLOCK::holdMask, i, LOCK_LOCKTAG, LOCKBIT_ON, PGPROC::lockGroupLeader, LOCKTAG_PAGE, LOCKTAG_RELATION_EXTEND, MAX_LOCKMODES, MyProc, PROCLOCKTAG::myProc, LockMethodData::numLockModes, PANIC, PROCLOCK_PRINT, LOCK::procLocks, and PROCLOCK::tag.

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

◆ LockHasWaiters()

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

Definition at line 634 of file lock.c.

635 {
636  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
637  LockMethod lockMethodTable;
638  LOCALLOCKTAG localtag;
639  LOCALLOCK *locallock;
640  LOCK *lock;
641  PROCLOCK *proclock;
642  LWLock *partitionLock;
643  bool hasWaiters = false;
644 
645  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
646  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
647  lockMethodTable = LockMethods[lockmethodid];
648  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
649  elog(ERROR, "unrecognized lock mode: %d", lockmode);
650 
651 #ifdef LOCK_DEBUG
652  if (LOCK_DEBUG_ENABLED(locktag))
653  elog(LOG, "LockHasWaiters: lock [%u,%u] %s",
654  locktag->locktag_field1, locktag->locktag_field2,
655  lockMethodTable->lockModeNames[lockmode]);
656 #endif
657 
658  /*
659  * Find the LOCALLOCK entry for this lock and lockmode
660  */
661  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
662  localtag.lock = *locktag;
663  localtag.mode = lockmode;
664 
665  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
666  &localtag,
667  HASH_FIND, NULL);
668 
669  /*
670  * let the caller print its own error message, too. Do not ereport(ERROR).
671  */
672  if (!locallock || locallock->nLocks <= 0)
673  {
674  elog(WARNING, "you don't own a lock of type %s",
675  lockMethodTable->lockModeNames[lockmode]);
676  return false;
677  }
678 
679  /*
680  * Check the shared lock table.
681  */
682  partitionLock = LockHashPartitionLock(locallock->hashcode);
683 
684  LWLockAcquire(partitionLock, LW_SHARED);
685 
686  /*
687  * We don't need to re-find the lock or proclock, since we kept their
688  * addresses in the locallock table, and they couldn't have been removed
689  * while we were holding a lock on them.
690  */
691  lock = locallock->lock;
692  LOCK_PRINT("LockHasWaiters: found", lock, lockmode);
693  proclock = locallock->proclock;
694  PROCLOCK_PRINT("LockHasWaiters: found", proclock);
695 
696  /*
697  * Double-check that we are actually holding a lock of the type we want to
698  * release.
699  */
700  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
701  {
702  PROCLOCK_PRINT("LockHasWaiters: WRONGTYPE", proclock);
703  LWLockRelease(partitionLock);
704  elog(WARNING, "you don't own a lock of type %s",
705  lockMethodTable->lockModeNames[lockmode]);
706  RemoveLocalLock(locallock);
707  return false;
708  }
709 
710  /*
711  * Do the checking.
712  */
713  if ((lockMethodTable->conflictTab[lockmode] & lock->waitMask) != 0)
714  hasWaiters = true;
715 
716  LWLockRelease(partitionLock);
717 
718  return hasWaiters;
719 }
#define WARNING
Definition: elog.h:36

References LockMethodData::conflictTab, elog(), ERROR, HASH_FIND, hash_search(), LOCALLOCK::hashcode, PROCLOCK::holdMask, lengthof, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKBIT_ON, LockHashPartitionLock, LockMethodLocalHash, LockMethods, LockMethodData::lockModeNames, 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().

◆ LockHeldByMe()

bool LockHeldByMe ( const LOCKTAG locktag,
LOCKMODE  lockmode 
)

Definition at line 598 of file lock.c.

599 {
600  LOCALLOCKTAG localtag;
601  LOCALLOCK *locallock;
602 
603  /*
604  * See if there is a LOCALLOCK entry for this lock and lockmode
605  */
606  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
607  localtag.lock = *locktag;
608  localtag.mode = lockmode;
609 
610  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
611  &localtag,
612  HASH_FIND, NULL);
613 
614  return (locallock && locallock->nLocks > 0);
615 }

References HASH_FIND, hash_search(), LOCALLOCKTAG::lock, LockMethodLocalHash, MemSet, LOCALLOCKTAG::mode, and LOCALLOCK::nLocks.

Referenced by CheckRelationLockedByMe().

◆ LockReassignCurrentOwner()

void LockReassignCurrentOwner ( LOCALLOCK **  locallocks,
int  nlocks 
)

Definition at line 2544 of file lock.c.

2545 {
2547 
2548  Assert(parent != NULL);
2549 
2550  if (locallocks == NULL)
2551  {
2552  HASH_SEQ_STATUS status;
2553  LOCALLOCK *locallock;
2554 
2556 
2557  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2558  LockReassignOwner(locallock, parent);
2559  }
2560  else
2561  {
2562  int i;
2563 
2564  for (i = nlocks - 1; i >= 0; i--)
2565  LockReassignOwner(locallocks[i], parent);
2566  }
2567 }
static void LockReassignOwner(LOCALLOCK *locallock, ResourceOwner parent)
Definition: lock.c:2574
ResourceOwner ResourceOwnerGetParent(ResourceOwner owner)
Definition: resowner.c:819

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

Referenced by ResourceOwnerReleaseInternal().

◆ LockRelease()

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

Definition at line 1949 of file lock.c.

1950 {
1951  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
1952  LockMethod lockMethodTable;
1953  LOCALLOCKTAG localtag;
1954  LOCALLOCK *locallock;
1955  LOCK *lock;
1956  PROCLOCK *proclock;
1957  LWLock *partitionLock;
1958  bool wakeupNeeded;
1959 
1960  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
1961  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
1962  lockMethodTable = LockMethods[lockmethodid];
1963  if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
1964  elog(ERROR, "unrecognized lock mode: %d", lockmode);
1965 
1966 #ifdef LOCK_DEBUG
1967  if (LOCK_DEBUG_ENABLED(locktag))
1968  elog(LOG, "LockRelease: lock [%u,%u] %s",
1969  locktag->locktag_field1, locktag->locktag_field2,
1970  lockMethodTable->lockModeNames[lockmode]);
1971 #endif
1972 
1973  /*
1974  * Find the LOCALLOCK entry for this lock and lockmode
1975  */
1976  MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
1977  localtag.lock = *locktag;
1978  localtag.mode = lockmode;
1979 
1980  locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
1981  &localtag,
1982  HASH_FIND, NULL);
1983 
1984  /*
1985  * let the caller print its own error message, too. Do not ereport(ERROR).
1986  */
1987  if (!locallock || locallock->nLocks <= 0)
1988  {
1989  elog(WARNING, "you don't own a lock of type %s",
1990  lockMethodTable->lockModeNames[lockmode]);
1991  return false;
1992  }
1993 
1994  /*
1995  * Decrease the count for the resource owner.
1996  */
1997  {
1998  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
1999  ResourceOwner owner;
2000  int i;
2001 
2002  /* Identify owner for lock */
2003  if (sessionLock)
2004  owner = NULL;
2005  else
2006  owner = CurrentResourceOwner;
2007 
2008  for (i = locallock->numLockOwners - 1; i >= 0; i--)
2009  {
2010  if (lockOwners[i].owner == owner)
2011  {
2012  Assert(lockOwners[i].nLocks > 0);
2013  if (--lockOwners[i].nLocks == 0)
2014  {
2015  if (owner != NULL)
2016  ResourceOwnerForgetLock(owner, locallock);
2017  /* compact out unused slot */
2018  locallock->numLockOwners--;
2019  if (i < locallock->numLockOwners)
2020  lockOwners[i] = lockOwners[locallock->numLockOwners];
2021  }
2022  break;
2023  }
2024  }
2025  if (i < 0)
2026  {
2027  /* don't release a lock belonging to another owner */
2028  elog(WARNING, "you don't own a lock of type %s",
2029  lockMethodTable->lockModeNames[lockmode]);
2030  return false;
2031  }
2032  }
2033 
2034  /*
2035  * Decrease the total local count. If we're still holding the lock, we're
2036  * done.
2037  */
2038  locallock->nLocks--;
2039 
2040  if (locallock->nLocks > 0)
2041  return true;
2042 
2043  /*
2044  * At this point we can no longer suppose we are clear of invalidation
2045  * messages related to this lock. Although we'll delete the LOCALLOCK
2046  * object before any intentional return from this routine, it seems worth
2047  * the trouble to explicitly reset lockCleared right now, just in case
2048  * some error prevents us from deleting the LOCALLOCK.
2049  */
2050  locallock->lockCleared = false;
2051 
2052  /* Attempt fast release of any lock eligible for the fast path. */
2053  if (EligibleForRelationFastPath(locktag, lockmode) &&
2055  {
2056  bool released;
2057 
2058  /*
2059  * We might not find the lock here, even if we originally entered it
2060  * here. Another backend may have moved it to the main table.
2061  */
2063  released = FastPathUnGrantRelationLock(locktag->locktag_field2,
2064  lockmode);
2066  if (released)
2067  {
2068  RemoveLocalLock(locallock);
2069  return true;
2070  }
2071  }
2072 
2073  /*
2074  * Otherwise we've got to mess with the shared lock table.
2075  */
2076  partitionLock = LockHashPartitionLock(locallock->hashcode);
2077 
2078  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2079 
2080  /*
2081  * Normally, we don't need to re-find the lock or proclock, since we kept
2082  * their addresses in the locallock table, and they couldn't have been
2083  * removed while we were holding a lock on them. But it's possible that
2084  * the lock was taken fast-path and has since been moved to the main hash
2085  * table by another backend, in which case we will need to look up the
2086  * objects here. We assume the lock field is NULL if so.
2087  */
2088  lock = locallock->lock;
2089  if (!lock)
2090  {
2091  PROCLOCKTAG proclocktag;
2092 
2093  Assert(EligibleForRelationFastPath(locktag, lockmode));
2095  locktag,
2096  locallock->hashcode,
2097  HASH_FIND,
2098  NULL);
2099  if (!lock)
2100  elog(ERROR, "failed to re-find shared lock object");
2101  locallock->lock = lock;
2102 
2103  proclocktag.myLock = lock;
2104  proclocktag.myProc = MyProc;
2106  &proclocktag,
2107  HASH_FIND,
2108  NULL);
2109  if (!locallock->proclock)
2110  elog(ERROR, "failed to re-find shared proclock object");
2111  }
2112  LOCK_PRINT("LockRelease: found", lock, lockmode);
2113  proclock = locallock->proclock;
2114  PROCLOCK_PRINT("LockRelease: found", proclock);
2115 
2116  /*
2117  * Double-check that we are actually holding a lock of the type we want to
2118  * release.
2119  */
2120  if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
2121  {
2122  PROCLOCK_PRINT("LockRelease: WRONGTYPE", proclock);
2123  LWLockRelease(partitionLock);
2124  elog(WARNING, "you don't own a lock of type %s",
2125  lockMethodTable->lockModeNames[lockmode]);
2126  RemoveLocalLock(locallock);
2127  return false;
2128  }
2129 
2130  /*
2131  * Do the releasing. CleanUpLock will waken any now-wakable waiters.
2132  */
2133  wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
2134 
2135  CleanUpLock(lock, proclock,
2136  lockMethodTable, locallock->hashcode,
2137  wakeupNeeded);
2138 
2139  LWLockRelease(partitionLock);
2140 
2141  RemoveLocalLock(locallock);
2142  return true;
2143 }
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode, PROCLOCK *proclock, LockMethod lockMethodTable)
Definition: lock.c:1573
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock, LockMethod lockMethodTable, uint32 hashcode, bool wakeupNeeded)
Definition: lock.c:1630
static bool FastPathUnGrantRelationLock(Oid relid, LOCKMODE lockmode)
Definition: lock.c:2657
void ResourceOwnerForgetLock(ResourceOwner owner, LOCALLOCK *locallock)
Definition: resowner.c:1070

References Assert(), CleanUpLock(), CurrentResourceOwner, EligibleForRelationFastPath, elog(), ERROR, FastPathLocalUseCount, FastPathUnGrantRelationLock(), PGPROC::fpInfoLock, 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, LockMethodLocalHash, LockMethodLockHash, LockMethodProcLockHash, LockMethods, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, 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(), StandbyReleaseXidEntryLocks(), UnlockApplyTransactionForSession(), UnlockDatabaseObject(), UnlockPage(), UnlockRelation(), UnlockRelationForExtension(), UnlockRelationId(), UnlockRelationIdForSession(), UnlockRelationOid(), UnlockSharedObject(), UnlockSharedObjectForSession(), UnlockTuple(), VirtualXactLock(), XactLockForVirtualXact(), XactLockTableDelete(), and XactLockTableWait().

◆ LockReleaseAll()

void LockReleaseAll ( LOCKMETHODID  lockmethodid,
bool  allLocks 
)

Definition at line 2154 of file lock.c.

2155 {
2156  HASH_SEQ_STATUS status;
2157  LockMethod lockMethodTable;
2158  int i,
2159  numLockModes;
2160  LOCALLOCK *locallock;
2161  LOCK *lock;
2162  int partition;
2163  bool have_fast_path_lwlock = false;
2164 
2165  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2166  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2167  lockMethodTable = LockMethods[lockmethodid];
2168 
2169 #ifdef LOCK_DEBUG
2170  if (*(lockMethodTable->trace_flag))
2171  elog(LOG, "LockReleaseAll: lockmethod=%d", lockmethodid);
2172 #endif
2173 
2174  /*
2175  * Get rid of our fast-path VXID lock, if appropriate. Note that this is
2176  * the only way that the lock we hold on our own VXID can ever get
2177  * released: it is always and only released when a toplevel transaction
2178  * ends.
2179  */
2180  if (lockmethodid == DEFAULT_LOCKMETHOD)
2182 
2183  numLockModes = lockMethodTable->numLockModes;
2184 
2185  /*
2186  * First we run through the locallock table and get rid of unwanted
2187  * entries, then we scan the process's proclocks and get rid of those. We
2188  * do this separately because we may have multiple locallock entries
2189  * pointing to the same proclock, and we daren't end up with any dangling
2190  * pointers. Fast-path locks are cleaned up during the locallock table
2191  * scan, though.
2192  */
2194 
2195  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2196  {
2197  /*
2198  * If the LOCALLOCK entry is unused, we must've run out of shared
2199  * memory while trying to set up this lock. Just forget the local
2200  * entry.
2201  */
2202  if (locallock->nLocks == 0)
2203  {
2204  RemoveLocalLock(locallock);
2205  continue;
2206  }
2207 
2208  /* Ignore items that are not of the lockmethod to be removed */
2209  if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2210  continue;
2211 
2212  /*
2213  * If we are asked to release all locks, we can just zap the entry.
2214  * Otherwise, must scan to see if there are session locks. We assume
2215  * there is at most one lockOwners entry for session locks.
2216  */
2217  if (!allLocks)
2218  {
2219  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
2220 
2221  /* If session lock is above array position 0, move it down to 0 */
2222  for (i = 0; i < locallock->numLockOwners; i++)
2223  {
2224  if (lockOwners[i].owner == NULL)
2225  lockOwners[0] = lockOwners[i];
2226  else
2227  ResourceOwnerForgetLock(lockOwners[i].owner, locallock);
2228  }
2229 
2230  if (locallock->numLockOwners > 0 &&
2231  lockOwners[0].owner == NULL &&
2232  lockOwners[0].nLocks > 0)
2233  {
2234  /* Fix the locallock to show just the session locks */
2235  locallock->nLocks = lockOwners[0].nLocks;
2236  locallock->numLockOwners = 1;
2237  /* We aren't deleting this locallock, so done */
2238  continue;
2239  }
2240  else
2241  locallock->numLockOwners = 0;
2242  }
2243 
2244  /*
2245  * If the lock or proclock pointers are NULL, this lock was taken via
2246  * the relation fast-path (and is not known to have been transferred).
2247  */
2248  if (locallock->proclock == NULL || locallock->lock == NULL)
2249  {
2250  LOCKMODE lockmode = locallock->tag.mode;
2251  Oid relid;
2252 
2253  /* Verify that a fast-path lock is what we've got. */
2254  if (!EligibleForRelationFastPath(&locallock->tag.lock, lockmode))
2255  elog(PANIC, "locallock table corrupted");
2256 
2257  /*
2258  * If we don't currently hold the LWLock that protects our
2259  * fast-path data structures, we must acquire it before attempting
2260  * to release the lock via the fast-path. We will continue to
2261  * hold the LWLock until we're done scanning the locallock table,
2262  * unless we hit a transferred fast-path lock. (XXX is this
2263  * really such a good idea? There could be a lot of entries ...)
2264  */
2265  if (!have_fast_path_lwlock)
2266  {
2268  have_fast_path_lwlock = true;
2269  }
2270 
2271  /* Attempt fast-path release. */
2272  relid = locallock->tag.lock.locktag_field2;
2273  if (FastPathUnGrantRelationLock(relid, lockmode))
2274  {
2275  RemoveLocalLock(locallock);
2276  continue;
2277  }
2278 
2279  /*
2280  * Our lock, originally taken via the fast path, has been
2281  * transferred to the main lock table. That's going to require
2282  * some extra work, so release our fast-path lock before starting.
2283  */
2285  have_fast_path_lwlock = false;
2286 
2287  /*
2288  * Now dump the lock. We haven't got a pointer to the LOCK or
2289  * PROCLOCK in this case, so we have to handle this a bit
2290  * differently than a normal lock release. Unfortunately, this
2291  * requires an extra LWLock acquire-and-release cycle on the
2292  * partitionLock, but hopefully it shouldn't happen often.
2293  */
2294  LockRefindAndRelease(lockMethodTable, MyProc,
2295  &locallock->tag.lock, lockmode, false);
2296  RemoveLocalLock(locallock);
2297  continue;
2298  }
2299 
2300  /* Mark the proclock to show we need to release this lockmode */
2301  if (locallock->nLocks > 0)
2302  locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
2303 
2304  /* And remove the locallock hashtable entry */
2305  RemoveLocalLock(locallock);
2306  }
2307 
2308  /* Done with the fast-path data structures */
2309  if (have_fast_path_lwlock)
2311 
2312  /*
2313  * Now, scan each lock partition separately.
2314  */
2315  for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
2316  {
2317  LWLock *partitionLock;
2318  dlist_head *procLocks = &MyProc->myProcLocks[partition];
2319  dlist_mutable_iter proclock_iter;
2320 
2321  partitionLock = LockHashPartitionLockByIndex(partition);
2322 
2323  /*
2324  * If the proclock list for this partition is empty, we can skip
2325  * acquiring the partition lock. This optimization is trickier than
2326  * it looks, because another backend could be in process of adding
2327  * something to our proclock list due to promoting one of our
2328  * fast-path locks. However, any such lock must be one that we
2329  * decided not to delete above, so it's okay to skip it again now;
2330  * we'd just decide not to delete it again. We must, however, be
2331  * careful to re-fetch the list header once we've acquired the
2332  * partition lock, to be sure we have a valid, up-to-date pointer.
2333  * (There is probably no significant risk if pointer fetch/store is
2334  * atomic, but we don't wish to assume that.)
2335  *
2336  * XXX This argument assumes that the locallock table correctly
2337  * represents all of our fast-path locks. While allLocks mode
2338  * guarantees to clean up all of our normal locks regardless of the
2339  * locallock situation, we lose that guarantee for fast-path locks.
2340  * This is not ideal.
2341  */
2342  if (dlist_is_empty(procLocks))
2343  continue; /* needn't examine this partition */
2344 
2345  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2346 
2347  dlist_foreach_modify(proclock_iter, procLocks)
2348  {
2349  PROCLOCK *proclock = dlist_container(PROCLOCK, procLink, proclock_iter.cur);
2350  bool wakeupNeeded = false;
2351 
2352  Assert(proclock->tag.myProc == MyProc);
2353 
2354  lock = proclock->tag.myLock;
2355 
2356  /* Ignore items that are not of the lockmethod to be removed */
2357  if (LOCK_LOCKMETHOD(*lock) != lockmethodid)
2358  continue;
2359 
2360  /*
2361  * In allLocks mode, force release of all locks even if locallock
2362  * table had problems
2363  */
2364  if (allLocks)
2365  proclock->releaseMask = proclock->holdMask;
2366  else
2367  Assert((proclock->releaseMask & ~proclock->holdMask) == 0);
2368 
2369  /*
2370  * Ignore items that have nothing to be released, unless they have
2371  * holdMask == 0 and are therefore recyclable
2372  */
2373  if (proclock->releaseMask == 0 && proclock->holdMask != 0)
2374  continue;
2375 
2376  PROCLOCK_PRINT("LockReleaseAll", proclock);
2377  LOCK_PRINT("LockReleaseAll", lock, 0);
2378  Assert(lock->nRequested >= 0);
2379  Assert(lock->nGranted >= 0);
2380  Assert(lock->nGranted <= lock->nRequested);
2381  Assert((proclock->holdMask & ~lock->grantMask) == 0);
2382 
2383  /*
2384  * Release the previously-marked lock modes
2385  */
2386  for (i = 1; i <= numLockModes; i++)
2387  {
2388  if (proclock->releaseMask & LOCKBIT_ON(i))
2389  wakeupNeeded |= UnGrantLock(lock, i, proclock,
2390  lockMethodTable);
2391  }
2392  Assert((lock->nRequested >= 0) && (lock->nGranted >= 0));
2393  Assert(lock->nGranted <= lock->nRequested);
2394  LOCK_PRINT("LockReleaseAll: updated", lock, 0);
2395 
2396  proclock->releaseMask = 0;
2397 
2398  /* CleanUpLock will wake up waiters if needed. */
2399  CleanUpLock(lock, proclock,
2400  lockMethodTable,
2401  LockTagHashCode(&lock->tag),
2402  wakeupNeeded);
2403  } /* loop over PROCLOCKs within this partition */
2404 
2405  LWLockRelease(partitionLock);
2406  } /* loop over partitions */
2407 
2408 #ifdef LOCK_DEBUG
2409  if (*(lockMethodTable->trace_flag))
2410  elog(LOG, "LockReleaseAll done");
2411 #endif
2412 }
#define dlist_foreach_modify(iter, lhead)
Definition: ilist.h:640
void VirtualXactLockTableCleanup(void)
Definition: lock.c:4435
#define LOCALLOCK_LOCKMETHOD(llock)
Definition: lock.h:443
int64 nLocks
Definition: lock.h:423
const bool * trace_flag
Definition: lock.h:113
dlist_node * cur
Definition: ilist.h:200

References Assert(), CleanUpLock(), dlist_mutable_iter::cur, DEFAULT_LOCKMETHOD, dlist_container, dlist_foreach_modify, dlist_is_empty(), EligibleForRelationFastPath, elog(), ERROR, FastPathUnGrantRelationLock(), PGPROC::fpInfoLock, 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, LockMethodLocalHash, LockMethods, 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, LOCALLOCKOWNER::owner, PANIC, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), ResourceOwnerForgetLock(), LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, LockMethodData::trace_flag, UnGrantLock(), and VirtualXactLockTableCleanup().

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

◆ LockReleaseCurrentOwner()

void LockReleaseCurrentOwner ( LOCALLOCK **  locallocks,
int  nlocks 
)

Definition at line 2449 of file lock.c.

2450 {
2451  if (locallocks == NULL)
2452  {
2453  HASH_SEQ_STATUS status;
2454  LOCALLOCK *locallock;
2455 
2457 
2458  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2459  ReleaseLockIfHeld(locallock, false);
2460  }
2461  else
2462  {
2463  int i;
2464 
2465  for (i = nlocks - 1; i >= 0; i--)
2466  ReleaseLockIfHeld(locallocks[i], false);
2467  }
2468 }
static void ReleaseLockIfHeld(LOCALLOCK *locallock, bool sessionLock)
Definition: lock.c:2484

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

Referenced by ResourceOwnerReleaseInternal().

◆ LockReleaseSession()

void LockReleaseSession ( LOCKMETHODID  lockmethodid)

Definition at line 2419 of file lock.c.

2420 {
2421  HASH_SEQ_STATUS status;
2422  LOCALLOCK *locallock;
2423 
2424  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2425  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2426 
2428 
2429  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2430  {
2431  /* Ignore items that are not of the specified lock method */
2432  if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2433  continue;
2434 
2435  ReleaseLockIfHeld(locallock, true);
2436  }
2437 }

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

Referenced by pg_advisory_unlock_all().

◆ LockShmemSize()

Size LockShmemSize ( void  )

Definition at line 3559 of file lock.c.

3560 {
3561  Size size = 0;
3562  long max_table_size;
3563 
3564  /* lock hash table */
3565  max_table_size = NLOCKENTS();
3566  size = add_size(size, hash_estimate_size(max_table_size, sizeof(LOCK)));
3567 
3568  /* proclock hash table */
3569  max_table_size *= 2;
3570  size = add_size(size, hash_estimate_size(max_table_size, sizeof(PROCLOCK)));
3571 
3572  /*
3573  * Since NLOCKENTS is only an estimate, add 10% safety margin.
3574  */
3575  size = add_size(size, size / 10);
3576 
3577  return size;
3578 }
size_t Size
Definition: c.h:589
Size hash_estimate_size(long num_entries, Size entrysize)
Definition: dynahash.c:781
Size add_size(Size s1, Size s2)
Definition: shmem.c:502

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

Referenced by CalculateShmemSize().

◆ LockTagHashCode()

uint32 LockTagHashCode ( const LOCKTAG locktag)

Definition at line 517 of file lock.c.

518 {
519  return get_hash_value(LockMethodLockHash, (const void *) locktag);
520 }
uint32 get_hash_value(HTAB *hashp, const void *keyPtr)
Definition: dynahash.c:909

References get_hash_value(), and LockMethodLockHash.

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

◆ LockWaiterCount()

int LockWaiterCount ( const LOCKTAG locktag)

Definition at line 4646 of file lock.c.

4647 {
4648  LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
4649  LOCK *lock;
4650  bool found;
4651  uint32 hashcode;
4652  LWLock *partitionLock;
4653  int waiters = 0;
4654 
4655  if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4656  elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4657 
4658  hashcode = LockTagHashCode(locktag);
4659  partitionLock = LockHashPartitionLock(hashcode);
4660  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4661 
4663  locktag,
4664  hashcode,
4665  HASH_FIND,
4666  &found);
4667  if (found)
4668  {
4669  Assert(lock != NULL);
4670  waiters = lock->nRequested;
4671  }
4672  LWLockRelease(partitionLock);
4673 
4674  return waiters;
4675 }

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

Referenced by RelationExtensionLockWaiterCount().

◆ MarkLockClear()

void MarkLockClear ( LOCALLOCK locallock)

Definition at line 1794 of file lock.c.

1795 {
1796  Assert(locallock->nLocks > 0);
1797  locallock->lockCleared = true;
1798 }

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

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

◆ PostPrepare_Locks()

void PostPrepare_Locks ( TransactionId  xid)

Definition at line 3375 of file lock.c.

3376 {
3377  PGPROC *newproc = TwoPhaseGetDummyProc(xid, false);
3378  HASH_SEQ_STATUS status;
3379  LOCALLOCK *locallock;
3380  LOCK *lock;
3381  PROCLOCK *proclock;
3382  PROCLOCKTAG proclocktag;
3383  int partition;
3384 
3385  /* Can't prepare a lock group follower. */
3386  Assert(MyProc->lockGroupLeader == NULL ||
3388 
3389  /* This is a critical section: any error means big trouble */
3391 
3392  /*
3393  * First we run through the locallock table and get rid of unwanted
3394  * entries, then we scan the process's proclocks and transfer them to the
3395  * target proc.
3396  *
3397  * We do this separately because we may have multiple locallock entries
3398  * pointing to the same proclock, and we daren't end up with any dangling
3399  * pointers.
3400  */
3402 
3403  while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3404  {
3405  LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3406  bool haveSessionLock;
3407  bool haveXactLock;
3408  int i;
3409 
3410  if (locallock->proclock == NULL || locallock->lock == NULL)
3411  {
3412  /*
3413  * We must've run out of shared memory while trying to set up this
3414  * lock. Just forget the local entry.
3415  */
3416  Assert(locallock->nLocks == 0);
3417  RemoveLocalLock(locallock);
3418  continue;
3419  }
3420 
3421  /* Ignore VXID locks */
3422  if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3423  continue;
3424 
3425  /* Scan to see whether we hold it at session or transaction level */
3426  haveSessionLock = haveXactLock = false;
3427  for (i = locallock->numLockOwners - 1; i >= 0; i--)
3428  {
3429  if (lockOwners[i].owner == NULL)
3430  haveSessionLock = true;
3431  else
3432  haveXactLock = true;
3433  }
3434 
3435  /* Ignore it if we have only session lock */
3436  if (!haveXactLock)
3437  continue;
3438 
3439  /* This can't happen, because we already checked it */
3440  if (haveSessionLock)
3441  ereport(PANIC,
3442  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3443  errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3444 
3445  /* Mark the proclock to show we need to release this lockmode */
3446  if (locallock->nLocks > 0)
3447  locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
3448 
3449  /* And remove the locallock hashtable entry */
3450  RemoveLocalLock(locallock);
3451  }
3452 
3453  /*
3454  * Now, scan each lock partition separately.
3455  */
3456  for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
3457  {
3458  LWLock *partitionLock;
3459  dlist_head *procLocks = &(MyProc->myProcLocks[partition]);
3460  dlist_mutable_iter proclock_iter;
3461 
3462  partitionLock = LockHashPartitionLockByIndex(partition);
3463 
3464  /*
3465  * If the proclock list for this partition is empty, we can skip
3466  * acquiring the partition lock. This optimization is safer than the
3467  * situation in LockReleaseAll, because we got rid of any fast-path
3468  * locks during AtPrepare_Locks, so there cannot be any case where
3469  * another backend is adding something to our lists now. For safety,
3470  * though, we code this the same way as in LockReleaseAll.
3471  */
3472  if (dlist_is_empty(procLocks))
3473  continue; /* needn't examine this partition */
3474 
3475  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
3476 
3477  dlist_foreach_modify(proclock_iter, procLocks)
3478  {
3479  proclock = dlist_container(PROCLOCK, procLink, proclock_iter.cur);
3480 
3481  Assert(proclock->tag.myProc == MyProc);
3482 
3483  lock = proclock->tag.myLock;
3484 
3485  /* Ignore VXID locks */
3487  continue;
3488 
3489  PROCLOCK_PRINT("PostPrepare_Locks", proclock);
3490  LOCK_PRINT("PostPrepare_Locks", lock, 0);
3491  Assert(lock->nRequested >= 0);
3492  Assert(lock->nGranted >= 0);
3493  Assert(lock->nGranted <= lock->nRequested);
3494  Assert((proclock->holdMask & ~lock->grantMask) == 0);
3495 
3496  /* Ignore it if nothing to release (must be a session lock) */
3497  if (proclock->releaseMask == 0)
3498  continue;
3499 
3500  /* Else we should be releasing all locks */
3501  if (proclock->releaseMask != proclock->holdMask)
3502  elog(PANIC, "we seem to have dropped a bit somewhere");
3503 
3504  /*
3505  * We cannot simply modify proclock->tag.myProc to reassign
3506  * ownership of the lock, because that's part of the hash key and
3507  * the proclock would then be in the wrong hash chain. Instead
3508  * use hash_update_hash_key. (We used to create a new hash entry,
3509  * but that risks out-of-memory failure if other processes are
3510  * busy making proclocks too.) We must unlink the proclock from
3511  * our procLink chain and put it into the new proc's chain, too.
3512  *
3513  * Note: the updated proclock hash key will still belong to the
3514  * same hash partition, cf proclock_hash(). So the partition lock
3515  * we already hold is sufficient for this.
3516  */
3517  dlist_delete(&proclock->procLink);
3518 
3519  /*
3520  * Create the new hash key for the proclock.
3521  */
3522  proclocktag.myLock = lock;
3523  proclocktag.myProc = newproc;
3524 
3525  /*
3526  * Update groupLeader pointer to point to the new proc. (We'd
3527  * better not be a member of somebody else's lock group!)
3528  */
3529  Assert(proclock->groupLeader == proclock->tag.myProc);
3530  proclock->groupLeader = newproc;
3531 
3532  /*
3533  * Update the proclock. We should not find any existing entry for
3534  * the same hash key, since there can be only one entry for any
3535  * given lock with my own proc.
3536  */
3538  proclock,
3539  &proclocktag))
3540  elog(PANIC, "duplicate entry found while reassigning a prepared transaction's locks");
3541 
3542  /* Re-link into the new proc's proclock list */
3543  dlist_push_tail(&newproc->myProcLocks[partition], &proclock->procLink);
3544 
3545  PROCLOCK_PRINT("PostPrepare_Locks: updated", proclock);
3546  } /* loop over PROCLOCKs within this partition */
3547 
3548  LWLockRelease(partitionLock);
3549  } /* loop over partitions */
3550 
3551  END_CRIT_SECTION();
3552 }
bool hash_update_hash_key(HTAB *hashp, void *existingEntry, const void *newKeyPtr)
Definition: dynahash.c:1157
#define START_CRIT_SECTION()
Definition: miscadmin.h:148
#define END_CRIT_SECTION()
Definition: miscadmin.h:150

References Assert(), dlist_mutable_iter::cur, dlist_container, dlist_delete(), dlist_foreach_modify, dlist_is_empty(), dlist_push_tail(), 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, LockMethodLocalHash, LockMethodProcLockHash, 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, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), START_CRIT_SECTION, LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, and TwoPhaseGetDummyProc().

Referenced by PrepareTransaction().

◆ RememberSimpleDeadLock()

void RememberSimpleDeadLock ( PGPROC proc1,
LOCKMODE  lockmode,
LOCK lock,
PGPROC proc2 
)

Definition at line 1145 of file deadlock.c.

1149 {
1150  DEADLOCK_INFO *info = &deadlockDetails[0];
1151 
1152  info->locktag = lock->tag;
1153  info->lockmode = lockmode;
1154  info->pid = proc1->pid;
1155  info++;
1156  info->locktag = proc2->waitLock->tag;
1157  info->lockmode = proc2->waitLockMode;
1158  info->pid = proc2->pid;
1159  nDeadlockDetails = 2;
1160 }

References deadlockDetails, DEADLOCK_INFO::lockmode, DEADLOCK_INFO::locktag, nDeadlockDetails, DEADLOCK_INFO::pid, PGPROC::pid, LOCK::tag, PGPROC::waitLock, and PGPROC::waitLockMode.

Referenced by ProcSleep().

◆ RemoveFromWaitQueue()

void RemoveFromWaitQueue ( PGPROC proc,
uint32  hashcode 
)

Definition at line 1893 of file lock.c.

1894 {
1895  LOCK *waitLock = proc->waitLock;
1896  PROCLOCK *proclock = proc->waitProcLock;
1897  LOCKMODE lockmode = proc->waitLockMode;
1898  LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*waitLock);
1899 
1900  /* Make sure proc is waiting */
1902  Assert(proc->links.next != NULL);
1903  Assert(waitLock);
1904  Assert(!dclist_is_empty(&waitLock->waitProcs));
1905  Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
1906 
1907  /* Remove proc from lock's wait queue */
1908  dclist_delete_from(&waitLock->waitProcs, &proc->links);
1909 
1910  /* Undo increments of request counts by waiting process */
1911  Assert(waitLock->nRequested > 0);
1912  Assert(waitLock->nRequested > proc->waitLock->nGranted);
1913  waitLock->nRequested--;
1914  Assert(waitLock->requested[lockmode] > 0);
1915  waitLock->requested[lockmode]--;
1916  /* don't forget to clear waitMask bit if appropriate */
1917  if (waitLock->granted[lockmode] == waitLock->requested[lockmode])
1918  waitLock->waitMask &= LOCKBIT_OFF(lockmode);
1919 
1920  /* Clean up the proc's own state, and pass it the ok/fail signal */
1921  proc->waitLock = NULL;
1922  proc->waitProcLock = NULL;
1924 
1925  /*
1926  * Delete the proclock immediately if it represents no already-held locks.
1927  * (This must happen now because if the owner of the lock decides to
1928  * release it, and the requested/granted counts then go to zero,
1929  * LockRelease expects there to be no remaining proclocks.) Then see if
1930  * any other waiters for the lock can be woken up now.
1931  */
1932  CleanUpLock(waitLock, proclock,
1933  LockMethods[lockmethodid], hashcode,
1934  true);
1935 }
static bool dclist_is_empty(const dclist_head *head)
Definition: ilist.h:682
static void dclist_delete_from(dclist_head *head, dlist_node *node)
Definition: ilist.h:763
@ PROC_WAIT_STATUS_WAITING
Definition: proc.h:125
@ PROC_WAIT_STATUS_ERROR
Definition: proc.h:126
PROCLOCK * waitProcLock
Definition: proc.h:224
ProcWaitStatus waitStatus
Definition: proc.h:168
dlist_node links
Definition: proc.h:164
dlist_node * next
Definition: ilist.h:140

References Assert(), CleanUpLock(), dclist_delete_from(), dclist_is_empty(), LOCK::granted, lengthof, PGPROC::links, LOCK_LOCKMETHOD, LOCKBIT_OFF, LockMethods, dlist_node::next, LOCK::nGranted, LOCK::nRequested, PROC_WAIT_STATUS_ERROR, PROC_WAIT_STATUS_WAITING, LOCK::requested, PGPROC::waitLock, PGPROC::waitLockMode, LOCK::waitMask, PGPROC::waitProcLock, LOCK::waitProcs, and PGPROC::waitStatus.

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

◆ VirtualXactLock()

bool VirtualXactLock ( VirtualTransactionId  vxid,
bool  wait 
)

Definition at line 4535 of file lock.c.

4536 {
4537  LOCKTAG tag;
4538  PGPROC *proc;
4540 
4542 
4544  /* no vxid lock; localTransactionId is a normal, locked XID */
4545  return XactLockForVirtualXact(vxid, vxid.localTransactionId, wait);
4546 
4547  SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
4548 
4549  /*
4550  * If a lock table entry must be made, this is the PGPROC on whose behalf
4551  * it must be done. Note that the transaction might end or the PGPROC
4552  * might be reassigned to a new backend before we get around to examining
4553  * it, but it doesn't matter. If we find upon examination that the
4554  * relevant lxid is no longer running here, that's enough to prove that
4555  * it's no longer running anywhere.
4556  */
4557  proc = BackendIdGetProc(vxid.backendId);
4558  if (proc == NULL)
4559  return XactLockForVirtualXact(vxid, InvalidTransactionId, wait);
4560 
4561  /*
4562  * We must acquire this lock before checking the backendId and lxid
4563  * against the ones we're waiting for. The target backend will only set
4564  * or clear lxid while holding this lock.
4565  */
4567 
4568  if (proc->backendId != vxid.backendId
4569  || proc->fpLocalTransactionId != vxid.localTransactionId)
4570  {
4571  /* VXID ended */
4572  LWLockRelease(&proc->fpInfoLock);
4573  return XactLockForVirtualXact(vxid, InvalidTransactionId, wait);
4574  }
4575 
4576  /*
4577  * If we aren't asked to wait, there's no need to set up a lock table
4578  * entry. The transaction is still in progress, so just return false.
4579  */
4580  if (!wait)
4581  {
4582  LWLockRelease(&proc->fpInfoLock);
4583  return false;
4584  }
4585 
4586  /*
4587  * OK, we're going to need to sleep on the VXID. But first, we must set
4588  * up the primary lock table entry, if needed (ie, convert the proc's
4589  * fast-path lock on its VXID to a regular lock).
4590  */
4591  if (proc->fpVXIDLock)
4592  {
4593  PROCLOCK *proclock;
4594  uint32 hashcode;
4595  LWLock *partitionLock;
4596 
4597  hashcode = LockTagHashCode(&tag);
4598 
4599  partitionLock = LockHashPartitionLock(hashcode);
4600  LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4601 
4603  &tag, hashcode, ExclusiveLock);
4604  if (!proclock)
4605  {
4606  LWLockRelease(partitionLock);
4607  LWLockRelease(&proc->fpInfoLock);
4608  ereport(ERROR,
4609  (errcode(ERRCODE_OUT_OF_MEMORY),
4610  errmsg("out of shared memory"),
4611  errhint("You might need to increase max_locks_per_transaction.")));
4612  }
4613  GrantLock(proclock->tag.myLock, proclock, ExclusiveLock);
4614 
4615  LWLockRelease(partitionLock);
4616 
4617  proc->fpVXIDLock = false;
4618  }
4619 
4620  /*
4621  * If the proc has an XID now, we'll avoid a TwoPhaseGetXidByVirtualXID()
4622  * search. The proc might have assigned this XID but not yet locked it,
4623  * in which case the proc will lock this XID before releasing the VXID.
4624  * The fpInfoLock critical section excludes VirtualXactLockTableCleanup(),
4625  * so we won't save an XID of a different VXID. It doesn't matter whether
4626  * we save this before or after setting up the primary lock table entry.
4627  */
4628  xid = proc->xid;
4629 
4630  /* Done with proc->fpLockBits */
4631  LWLockRelease(&proc->fpInfoLock);
4632 
4633  /* Time to wait. */
4634  (void) LockAcquire(&tag, ShareLock, false, false);
4635 
4636  LockRelease(&tag, ShareLock, false);
4637  return XactLockForVirtualXact(vxid, xid, wait);
4638 }
static bool XactLockForVirtualXact(VirtualTransactionId vxid, TransactionId xid, bool wait)
Definition: lock.c:4484
LockAcquireResult LockAcquire(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait)
Definition: lock.c:747
bool LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
Definition: lock.c:1949
#define VirtualTransactionIdIsRecoveredPreparedXact(vxid)
Definition: lock.h:69
#define ShareLock
Definition: lockdefs.h:40
PGPROC * BackendIdGetProc(int backendID)
Definition: sinvaladt.c:385
#define InvalidTransactionId
Definition: transam.h:31

References Assert(), VirtualTransactionId::backendId, PGPROC::backendId, BackendIdGetProc(), DEFAULT_LOCKMETHOD, ereport, errcode(), errhint(), errmsg(), ERROR, ExclusiveLock, PGPROC::fpInfoLock, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, GrantLock(), InvalidTransactionId, VirtualTransactionId::localTransactionId, LockAcquire(), LockHashPartitionLock, LockMethods, LockRelease(), LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PROCLOCKTAG::myLock, SET_LOCKTAG_VIRTUALTRANSACTION, SetupLockInTable(), ShareLock, PROCLOCK::tag, VirtualTransactionIdIsRecoveredPreparedXact, VirtualTransactionIdIsValid, XactLockForVirtualXact(), and PGPROC::xid.

Referenced by ResolveRecoveryConflictWithVirtualXIDs(), WaitForLockersMultiple(), and WaitForOlderSnapshots().

◆ VirtualXactLockTableCleanup()

void VirtualXactLockTableCleanup ( void  )

Definition at line 4435 of file lock.c.

4436 {
4437  bool fastpath;
4438  LocalTransactionId lxid;
4439 
4441 
4442  /*
4443  * Clean up shared memory state.
4444  */
4446 
4447  fastpath = MyProc->fpVXIDLock;
4448  lxid = MyProc->fpLocalTransactionId;
4449  MyProc->fpVXIDLock = false;
4451 
4453 
4454  /*
4455  * If fpVXIDLock has been cleared without touching fpLocalTransactionId,
4456  * that means someone transferred the lock to the main lock table.
4457  */
4458  if (!fastpath && LocalTransactionIdIsValid(lxid))
4459  {
4460  VirtualTransactionId vxid;
4461  LOCKTAG locktag;
4462 
4463  vxid.backendId = MyBackendId;
4464  vxid.localTransactionId = lxid;
4465  SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid);
4466 
4468  &locktag, ExclusiveLock, false);
4469  }
4470 }
uint32 LocalTransactionId
Definition: c.h:638
BackendId MyBackendId
Definition: globals.c:85
#define LocalTransactionIdIsValid(lxid)
Definition: lock.h:66

References Assert(), VirtualTransactionId::backendId, PGPROC::backendId, DEFAULT_LOCKMETHOD, ExclusiveLock, PGPROC::fpInfoLock, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, InvalidBackendId, InvalidLocalTransactionId, VirtualTransactionId::localTransactionId, LocalTransactionIdIsValid, LockMethods, LockRefindAndRelease(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyBackendId, MyProc, and SET_LOCKTAG_VIRTUALTRANSACTION.

Referenced by LockReleaseAll(), and ShutdownRecoveryTransactionEnvironment().

◆ VirtualXactLockTableInsert()

Variable Documentation

◆ LockTagTypeNames

PGDLLIMPORT const char* const LockTagTypeNames[]
extern

Definition at line 29 of file lockfuncs.c.

Referenced by GetLockNameFromTagType(), and pg_lock_status().

◆ max_locks_per_xact

PGDLLIMPORT int max_locks_per_xact
extern

Definition at line 55 of file lock.c.

Referenced by CheckRequiredParameterValues(), InitControlFile(), and XLogReportParameters().