Header And Logo
|
#include "postgres.h"#include <signal.h>#include <unistd.h>#include "access/transam.h"#include "access/twophase.h"#include "access/twophase_rmgr.h"#include "miscadmin.h"#include "pg_trace.h"#include "pgstat.h"#include "storage/proc.h"#include "storage/sinvaladt.h"#include "storage/spin.h"#include "storage/standby.h"#include "utils/memutils.h"#include "utils/ps_status.h"#include "utils/resowner_private.h"
Go to the source code of this file.
Data Structures | |
| struct | TwoPhaseLockRecord |
| struct | FastPathStrongRelationLockData |
Defines | |
| #define | NLOCKENTS() mul_size(max_locks_per_xact, add_size(MaxBackends, max_prepared_xacts)) |
| #define | FAST_PATH_BITS_PER_SLOT 3 |
| #define | FAST_PATH_LOCKNUMBER_OFFSET 1 |
| #define | FAST_PATH_MASK ((1 << FAST_PATH_BITS_PER_SLOT) - 1) |
| #define | FAST_PATH_GET_BITS(proc, n) (((proc)->fpLockBits >> (FAST_PATH_BITS_PER_SLOT * n)) & FAST_PATH_MASK) |
| #define | FAST_PATH_BIT_POSITION(n, l) |
| #define | FAST_PATH_SET_LOCKMODE(proc, n, l) (proc)->fpLockBits |= UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l) |
| #define | FAST_PATH_CLEAR_LOCKMODE(proc, n, l) (proc)->fpLockBits &= ~(UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l)) |
| #define | FAST_PATH_CHECK_LOCKMODE(proc, n, l) ((proc)->fpLockBits & (UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l))) |
| #define | EligibleForRelationFastPath(locktag, mode) |
| #define | ConflictsWithRelationFastPath(locktag, mode) |
| #define | FAST_PATH_STRONG_LOCK_HASH_BITS 10 |
| #define | FAST_PATH_STRONG_LOCK_HASH_PARTITIONS (1 << FAST_PATH_STRONG_LOCK_HASH_BITS) |
| #define | FastPathStrongLockHashPartition(hashcode) ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) |
| #define | LOCK_PRINT(where, lock, type) |
| #define | PROCLOCK_PRINT(where, proclockP) |
Typedefs | |
| typedef struct TwoPhaseLockRecord | TwoPhaseLockRecord |
Functions | |
| static bool | FastPathGrantRelationLock (Oid relid, LOCKMODE lockmode) |
| static bool | FastPathUnGrantRelationLock (Oid relid, LOCKMODE lockmode) |
| static bool | FastPathTransferRelationLocks (LockMethod lockMethodTable, const LOCKTAG *locktag, uint32 hashcode) |
| static PROCLOCK * | FastPathGetRelationLockEntry (LOCALLOCK *locallock) |
| static uint32 | proclock_hash (const void *key, Size keysize) |
| static void | RemoveLocalLock (LOCALLOCK *locallock) |
| static PROCLOCK * | SetupLockInTable (LockMethod lockMethodTable, PGPROC *proc, const LOCKTAG *locktag, uint32 hashcode, LOCKMODE lockmode) |
| static void | GrantLockLocal (LOCALLOCK *locallock, ResourceOwner owner) |
| static void | BeginStrongLockAcquire (LOCALLOCK *locallock, uint32 fasthashcode) |
| static void | FinishStrongLockAcquire (void) |
| static void | WaitOnLock (LOCALLOCK *locallock, ResourceOwner owner) |
| static void | ReleaseLockIfHeld (LOCALLOCK *locallock, bool sessionLock) |
| static void | LockReassignOwner (LOCALLOCK *locallock, ResourceOwner parent) |
| static bool | UnGrantLock (LOCK *lock, LOCKMODE lockmode, PROCLOCK *proclock, LockMethod lockMethodTable) |
| static void | CleanUpLock (LOCK *lock, PROCLOCK *proclock, LockMethod lockMethodTable, uint32 hashcode, bool wakeupNeeded) |
| static void | LockRefindAndRelease (LockMethod lockMethodTable, PGPROC *proc, LOCKTAG *locktag, LOCKMODE lockmode, bool decrement_strong_lock_count) |
| void | InitLocks (void) |
| LockMethod | GetLocksMethodTable (const LOCK *lock) |
| uint32 | LockTagHashCode (const LOCKTAG *locktag) |
| static uint32 | ProcLockHashCode (const PROCLOCKTAG *proclocktag, uint32 hashcode) |
| bool | DoLockModesConflict (LOCKMODE mode1, LOCKMODE mode2) |
| bool | LockHasWaiters (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock) |
| LockAcquireResult | LockAcquire (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait) |
| LockAcquireResult | LockAcquireExtended (const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait, bool reportMemoryError) |
| int | LockCheckConflicts (LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock, PGPROC *proc) |
| void | GrantLock (LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode) |
| void | AbortStrongLockAcquire (void) |
| void | GrantAwaitedLock (void) |
| void | RemoveFromWaitQueue (PGPROC *proc, uint32 hashcode) |
| 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) |
| VirtualTransactionId * | GetLockConflicts (const LOCKTAG *locktag, LOCKMODE lockmode) |
| void | AtPrepare_Locks (void) |
| void | PostPrepare_Locks (TransactionId xid) |
| Size | LockShmemSize (void) |
| LockData * | GetLockStatusData (void) |
| xl_standby_lock * | GetRunningTransactionLocks (int *nlocks) |
| const char * | GetLockmodeName (LOCKMETHODID lockmethodid, LOCKMODE mode) |
| void | lock_twophase_recover (TransactionId xid, uint16 info, void *recdata, uint32 len) |
| void | lock_twophase_standby_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 | VirtualXactLockTableInsert (VirtualTransactionId vxid) |
| void | VirtualXactLockTableCleanup () |
| bool | VirtualXactLock (VirtualTransactionId vxid, bool wait) |
Variables | |
| int | max_locks_per_xact |
| static const LOCKMASK | LockConflicts [] |
| static const char *const | lock_mode_names [] |
| static bool | Dummy_trace = false |
| static const LockMethodData | default_lockmethod |
| static const LockMethodData | user_lockmethod |
| static const LockMethod | LockMethods [] |
| static int | FastPathLocalUseCount = 0 |
| FastPathStrongRelationLockData * | FastPathStrongRelationLocks |
| static HTAB * | LockMethodLockHash |
| static HTAB * | LockMethodProcLockHash |
| static HTAB * | LockMethodLocalHash |
| static LOCALLOCK * | StrongLockInProgress |
| static LOCALLOCK * | awaitedLock |
| static ResourceOwner | awaitedOwner |
| #define ConflictsWithRelationFastPath | ( | locktag, | ||
| mode | ||||
| ) |
((locktag)->locktag_lockmethodid == DEFAULT_LOCKMETHOD && \ (locktag)->locktag_type == LOCKTAG_RELATION && \ (locktag)->locktag_field1 != InvalidOid && \ (mode) > ShareUpdateExclusiveLock)
Definition at line 202 of file lock.c.
Referenced by GetLockConflicts(), lock_twophase_recover(), LockAcquireExtended(), and LockRefindAndRelease().
| #define EligibleForRelationFastPath | ( | locktag, | ||
| mode | ||||
| ) |
((locktag)->locktag_lockmethodid == DEFAULT_LOCKMETHOD && \ (locktag)->locktag_type == LOCKTAG_RELATION && \ (locktag)->locktag_field1 == MyDatabaseId && \ MyDatabaseId != InvalidOid && \ (mode) < ShareUpdateExclusiveLock)
Definition at line 196 of file lock.c.
Referenced by LockAcquireExtended(), LockRelease(), and LockReleaseAll().
| #define FAST_PATH_BIT_POSITION | ( | n, | ||
| l | ||||
| ) |
(AssertMacro((l) >= FAST_PATH_LOCKNUMBER_OFFSET), \ AssertMacro((l) < FAST_PATH_BITS_PER_SLOT+FAST_PATH_LOCKNUMBER_OFFSET), \ AssertMacro((n) < FP_LOCK_SLOTS_PER_BACKEND), \ ((l) - FAST_PATH_LOCKNUMBER_OFFSET + FAST_PATH_BITS_PER_SLOT * (n)))
| #define FAST_PATH_CHECK_LOCKMODE | ( | proc, | ||
| n, | ||||
| l | ||||
| ) | ((proc)->fpLockBits & (UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l))) |
Definition at line 185 of file lock.c.
Referenced by FastPathGetRelationLockEntry(), FastPathGrantRelationLock(), FastPathTransferRelationLocks(), and FastPathUnGrantRelationLock().
| #define FAST_PATH_CLEAR_LOCKMODE | ( | proc, | ||
| n, | ||||
| l | ||||
| ) | (proc)->fpLockBits &= ~(UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l)) |
Definition at line 183 of file lock.c.
Referenced by FastPathGetRelationLockEntry(), FastPathTransferRelationLocks(), and FastPathUnGrantRelationLock().
| #define FAST_PATH_GET_BITS | ( | proc, | ||
| n | ||||
| ) | (((proc)->fpLockBits >> (FAST_PATH_BITS_PER_SLOT * n)) & FAST_PATH_MASK) |
Definition at line 174 of file lock.c.
Referenced by FastPathGetRelationLockEntry(), FastPathGrantRelationLock(), FastPathTransferRelationLocks(), FastPathUnGrantRelationLock(), GetLockConflicts(), and GetLockStatusData().
| #define FAST_PATH_LOCKNUMBER_OFFSET 1 |
Definition at line 172 of file lock.c.
Referenced by FastPathTransferRelationLocks().
| #define FAST_PATH_SET_LOCKMODE | ( | proc, | ||
| n, | ||||
| l | ||||
| ) | (proc)->fpLockBits |= UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l) |
Definition at line 181 of file lock.c.
Referenced by FastPathGrantRelationLock().
| #define FAST_PATH_STRONG_LOCK_HASH_PARTITIONS (1 << FAST_PATH_STRONG_LOCK_HASH_BITS) |
| #define FastPathStrongLockHashPartition | ( | hashcode | ) | ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) |
Definition at line 232 of file lock.c.
Referenced by AbortStrongLockAcquire(), lock_twophase_recover(), LockAcquireExtended(), LockRefindAndRelease(), and RemoveLocalLock().
| #define LOCK_PRINT | ( | where, | ||
| lock, | ||||
| type | ||||
| ) |
Definition at line 334 of file lock.c.
Referenced by CleanUpLock(), GrantLock(), lock_twophase_recover(), LockAcquireExtended(), LockHasWaiters(), LockRelease(), LockReleaseAll(), PostPrepare_Locks(), SetupLockInTable(), UnGrantLock(), and WaitOnLock().
| #define NLOCKENTS | ( | ) | mul_size(max_locks_per_xact, add_size(MaxBackends, max_prepared_xacts)) |
Definition at line 53 of file lock.c.
Referenced by InitLocks(), and LockShmemSize().
| #define PROCLOCK_PRINT | ( | where, | ||
| proclockP | ||||
| ) |
Definition at line 335 of file lock.c.
Referenced by CleanUpLock(), lock_twophase_recover(), LockAcquireExtended(), LockCheckConflicts(), LockHasWaiters(), LockRefindAndRelease(), LockRelease(), LockReleaseAll(), PostPrepare_Locks(), SetupLockInTable(), and UnGrantLock().
| typedef struct TwoPhaseLockRecord TwoPhaseLockRecord |
| void AbortStrongLockAcquire | ( | void | ) |
Definition at line 1524 of file lock.c.
References Assert, FastPathStrongRelationLockData::count, FastPathStrongLockHashPartition, LOCALLOCK::hashcode, LOCALLOCK::holdsStrongLockCount, FastPathStrongRelationLockData::mutex, NULL, SpinLockAcquire, SpinLockRelease, and TRUE.
Referenced by LockAcquireExtended(), and LockErrorCleanup().
{
uint32 fasthashcode;
LOCALLOCK *locallock = StrongLockInProgress;
if (locallock == NULL)
return;
fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
Assert(locallock->holdsStrongLockCount == TRUE);
SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
FastPathStrongRelationLocks->count[fasthashcode]--;
locallock->holdsStrongLockCount = FALSE;
StrongLockInProgress = NULL;
SpinLockRelease(&FastPathStrongRelationLocks->mutex);
}
| void AtPrepare_Locks | ( | void | ) |
Definition at line 2926 of file lock.c.
References ereport, errcode(), errmsg(), ERROR, FastPathGetRelationLockEntry(), hash_seq_init(), hash_seq_search(), LOCALLOCK::holdsStrongLockCount, i, LOCALLOCK::lock, LOCALLOCKTAG::lock, TwoPhaseLockRecord::lockmode, LOCALLOCK::lockOwners, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_type, LOCKTAG_VIRTUALTRANSACTION, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, LOCALLOCK::nLocks, NULL, LOCALLOCK::numLockOwners, LOCALLOCK::proclock, RegisterTwoPhaseRecord(), PROCLOCK::tag, LOCALLOCK::tag, and TWOPHASE_RM_LOCK_ID.
Referenced by PrepareTransaction().
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
/*
* For the most part, we don't need to touch shared memory for this ---
* all the necessary state information is in the locallock table.
* Fast-path locks are an exception, however: we move any such locks to
* the main table before allowing PREPARE TRANSACTION to succeed.
*/
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
{
TwoPhaseLockRecord record;
LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
bool haveSessionLock;
bool haveXactLock;
int i;
/*
* Ignore VXID locks. We don't want those to be held by prepared
* transactions, since they aren't meaningful after a restart.
*/
if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
continue;
/* Ignore it if we don't actually hold the lock */
if (locallock->nLocks <= 0)
continue;
/* Scan to see whether we hold it at session or transaction level */
haveSessionLock = haveXactLock = false;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == NULL)
haveSessionLock = true;
else
haveXactLock = true;
}
/* Ignore it if we have only session lock */
if (!haveXactLock)
continue;
/*
* If we have both session- and transaction-level locks, fail. This
* should never happen with regular locks, since we only take those at
* session level in some special operations like VACUUM. It's
* possible to hit this with advisory locks, though.
*
* It would be nice if we could keep the session hold and give away
* the transactional hold to the prepared xact. However, that would
* require two PROCLOCK objects, and we cannot be sure that another
* PROCLOCK will be available when it comes time for PostPrepare_Locks
* to do the deed. So for now, we error out while we can still do so
* safely.
*/
if (haveSessionLock)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
/*
* If the local lock was taken via the fast-path, we need to move it
* to the primary lock table, or just get a pointer to the existing
* primary lock table entry if by chance it's already been
* transferred.
*/
if (locallock->proclock == NULL)
{
locallock->proclock = FastPathGetRelationLockEntry(locallock);
locallock->lock = locallock->proclock->tag.myLock;
}
/*
* Arrange to not release any strong lock count held by this lock
* entry. We must retain the count until the prepared transaction is
* committed or rolled back.
*/
locallock->holdsStrongLockCount = FALSE;
/*
* Create a 2PC record.
*/
memcpy(&(record.locktag), &(locallock->tag.lock), sizeof(LOCKTAG));
record.lockmode = locallock->tag.mode;
RegisterTwoPhaseRecord(TWOPHASE_RM_LOCK_ID, 0,
&record, sizeof(TwoPhaseLockRecord));
}
}
Definition at line 1488 of file lock.c.
References Assert, FastPathStrongRelationLockData::count, FALSE, LOCALLOCK::holdsStrongLockCount, FastPathStrongRelationLockData::mutex, NULL, SpinLockAcquire, and SpinLockRelease.
Referenced by LockAcquireExtended().
{
Assert(StrongLockInProgress == NULL);
Assert(locallock->holdsStrongLockCount == FALSE);
/*
* Adding to a memory location is not atomic, so we take a spinlock to
* ensure we don't collide with someone else trying to bump the count at
* the same time.
*
* XXX: It might be worth considering using an atomic fetch-and-add
* instruction here, on architectures where that is supported.
*/
SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
FastPathStrongRelationLocks->count[fasthashcode]++;
locallock->holdsStrongLockCount = TRUE;
StrongLockInProgress = locallock;
SpinLockRelease(&FastPathStrongRelationLocks->mutex);
}
| static void CleanUpLock | ( | LOCK * | lock, | |
| PROCLOCK * | proclock, | |||
| LockMethod | lockMethodTable, | |||
| uint32 | hashcode, | |||
| bool | wakeupNeeded | |||
| ) | [static] |
Definition at line 1405 of file lock.c.
References Assert, elog, HASH_REMOVE, hash_search_with_hash_value(), PROCLOCK::holdMask, LOCK_PRINT, PROCLOCK::lockLink, LOCK::nRequested, NULL, PANIC, PROCLOCK::procLink, PROCLOCK_PRINT, ProcLockHashCode(), LOCK::procLocks, ProcLockWakeup(), SHMQueueDelete(), SHMQueueEmpty(), LOCK::tag, and PROCLOCK::tag.
Referenced by LockRefindAndRelease(), LockRelease(), LockReleaseAll(), and RemoveFromWaitQueue().
{
/*
* If this was my last hold on this lock, delete my entry in the proclock
* table.
*/
if (proclock->holdMask == 0)
{
uint32 proclock_hashcode;
PROCLOCK_PRINT("CleanUpLock: deleting", proclock);
SHMQueueDelete(&proclock->lockLink);
SHMQueueDelete(&proclock->procLink);
proclock_hashcode = ProcLockHashCode(&proclock->tag, hashcode);
if (!hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &(proclock->tag),
proclock_hashcode,
HASH_REMOVE,
NULL))
elog(PANIC, "proclock table corrupted");
}
if (lock->nRequested == 0)
{
/*
* The caller just released the last lock, so garbage-collect the lock
* object.
*/
LOCK_PRINT("CleanUpLock: deleting", lock, 0);
Assert(SHMQueueEmpty(&(lock->procLocks)));
if (!hash_search_with_hash_value(LockMethodLockHash,
(void *) &(lock->tag),
hashcode,
HASH_REMOVE,
NULL))
elog(PANIC, "lock table corrupted");
}
else if (wakeupNeeded)
{
/* There are waiters on this lock, so wake them up. */
ProcLockWakeup(lockMethodTable, lock);
}
}
Definition at line 545 of file lock.c.
References LockMethodData::conflictTab, and LOCKBIT_ON.
Referenced by Do_MultiXactIdWait().
{
LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
if (lockMethodTable->conflictTab[mode1] & LOCKBIT_ON(mode2))
return true;
return false;
}
Definition at line 2522 of file lock.c.
References PGPROC::backendLock, elog, ereport, errcode(), errhint(), errmsg(), ERROR, FAST_PATH_CHECK_LOCKMODE, FAST_PATH_CLEAR_LOCKMODE, FAST_PATH_GET_BITS, PGPROC::fpRelId, GrantLock(), hash_search_with_hash_value(), LOCALLOCK::hashcode, LOCALLOCKTAG::lock, LockHashPartitionLock, LOCKTAG::locktag_field2, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, MyProc, NULL, ProcLockHashCode(), SetupLockInTable(), PROCLOCK::tag, and LOCALLOCK::tag.
Referenced by AtPrepare_Locks().
{
LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
LOCKTAG *locktag = &locallock->tag.lock;
PROCLOCK *proclock = NULL;
LWLockId partitionLock = LockHashPartitionLock(locallock->hashcode);
Oid relid = locktag->locktag_field2;
uint32 f;
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
uint32 lockmode;
/* Look for an allocated slot matching the given relid. */
if (relid != MyProc->fpRelId[f] || FAST_PATH_GET_BITS(MyProc, f) == 0)
continue;
/* If we don't have a lock of the given mode, forget it! */
lockmode = locallock->tag.mode;
if (!FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode))
break;
/* Find or create lock object. */
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
locallock->hashcode, lockmode);
if (!proclock)
{
LWLockRelease(partitionLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
}
GrantLock(proclock->tag.myLock, proclock, lockmode);
FAST_PATH_CLEAR_LOCKMODE(MyProc, f, lockmode);
LWLockRelease(partitionLock);
}
LWLockRelease(MyProc->backendLock);
/* Lock may have already been transferred by some other backend. */
if (proclock == NULL)
{
LOCK *lock;
PROCLOCKTAG proclocktag;
uint32 proclock_hashcode;
LWLockAcquire(partitionLock, LW_SHARED);
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(void *) locktag,
locallock->hashcode,
HASH_FIND,
NULL);
if (!lock)
elog(ERROR, "failed to re-find shared lock object");
proclocktag.myLock = lock;
proclocktag.myProc = MyProc;
proclock_hashcode = ProcLockHashCode(&proclocktag, locallock->hashcode);
proclock = (PROCLOCK *)
hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &proclocktag,
proclock_hashcode,
HASH_FIND,
NULL);
if (!proclock)
elog(ERROR, "failed to re-find shared proclock object");
LWLockRelease(partitionLock);
}
return proclock;
}
Definition at line 2374 of file lock.c.
References Assert, FAST_PATH_CHECK_LOCKMODE, FAST_PATH_GET_BITS, FAST_PATH_SET_LOCKMODE, FastPathLocalUseCount, PGPROC::fpRelId, and MyProc.
Referenced by LockAcquireExtended().
{
uint32 f;
uint32 unused_slot = FP_LOCK_SLOTS_PER_BACKEND;
/* Scan for existing entry for this relid, remembering empty slot. */
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
if (FAST_PATH_GET_BITS(MyProc, f) == 0)
unused_slot = f;
else if (MyProc->fpRelId[f] == relid)
{
Assert(!FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode));
FAST_PATH_SET_LOCKMODE(MyProc, f, lockmode);
return true;
}
}
/* If no existing entry, use any empty slot. */
if (unused_slot < FP_LOCK_SLOTS_PER_BACKEND)
{
MyProc->fpRelId[unused_slot] = relid;
FAST_PATH_SET_LOCKMODE(MyProc, unused_slot, lockmode);
++FastPathLocalUseCount;
return true;
}
/* No existing entry, and no empty slot. */
return false;
}
| static bool FastPathTransferRelationLocks | ( | LockMethod | lockMethodTable, | |
| const LOCKTAG * | locktag, | |||
| uint32 | hashcode | |||
| ) | [static] |
Definition at line 2440 of file lock.c.
References PROC_HDR::allProcCount, PROC_HDR::allProcs, PGPROC::backendLock, PGPROC::databaseId, FAST_PATH_CHECK_LOCKMODE, FAST_PATH_CLEAR_LOCKMODE, FAST_PATH_GET_BITS, FAST_PATH_LOCKNUMBER_OFFSET, PGPROC::fpRelId, GrantLock(), i, LockHashPartitionLock, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PROCLOCKTAG::myLock, ProcGlobal, SetupLockInTable(), and PROCLOCK::tag.
Referenced by LockAcquireExtended().
{
LWLockId partitionLock = LockHashPartitionLock(hashcode);
Oid relid = locktag->locktag_field2;
uint32 i;
/*
* Every PGPROC that can potentially hold a fast-path lock is present in
* ProcGlobal->allProcs. Prepared transactions are not, but any
* outstanding fast-path locks held by prepared transactions are
* transferred to the main lock table.
*/
for (i = 0; i < ProcGlobal->allProcCount; i++)
{
PGPROC *proc = &ProcGlobal->allProcs[i];
uint32 f;
LWLockAcquire(proc->backendLock, LW_EXCLUSIVE);
/*
* If the target backend isn't referencing the same database as the
* lock, then we needn't examine the individual relation IDs at all;
* none of them can be relevant.
*
* proc->databaseId is set at backend startup time and never changes
* thereafter, so it might be safe to perform this test before
* acquiring proc->backendLock. In particular, it's certainly safe to
* assume that if the target backend holds any fast-path locks, it
* must have performed a memory-fencing operation (in particular, an
* LWLock acquisition) since setting proc->databaseId. However, it's
* less clear that our backend is certain to have performed a memory
* fencing operation since the other backend set proc->databaseId. So
* for now, we test it after acquiring the LWLock just to be safe.
*/
if (proc->databaseId != locktag->locktag_field1)
{
LWLockRelease(proc->backendLock);
continue;
}
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
uint32 lockmode;
/* Look for an allocated slot matching the given relid. */
if (relid != proc->fpRelId[f] || FAST_PATH_GET_BITS(proc, f) == 0)
continue;
/* Find or create lock object. */
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
for (lockmode = FAST_PATH_LOCKNUMBER_OFFSET;
lockmode < FAST_PATH_LOCKNUMBER_OFFSET + FAST_PATH_BITS_PER_SLOT;
++lockmode)
{
PROCLOCK *proclock;
if (!FAST_PATH_CHECK_LOCKMODE(proc, f, lockmode))
continue;
proclock = SetupLockInTable(lockMethodTable, proc, locktag,
hashcode, lockmode);
if (!proclock)
{
LWLockRelease(partitionLock);
return false;
}
GrantLock(proclock->tag.myLock, proclock, lockmode);
FAST_PATH_CLEAR_LOCKMODE(proc, f, lockmode);
}
LWLockRelease(partitionLock);
}
LWLockRelease(proc->backendLock);
}
return true;
}
Definition at line 2411 of file lock.c.
References Assert, FAST_PATH_CHECK_LOCKMODE, FAST_PATH_CLEAR_LOCKMODE, FAST_PATH_GET_BITS, FastPathLocalUseCount, PGPROC::fpRelId, and MyProc.
Referenced by LockRelease(), and LockReleaseAll().
{
uint32 f;
bool result = false;
FastPathLocalUseCount = 0;
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
if (MyProc->fpRelId[f] == relid
&& FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode))
{
Assert(!result);
FAST_PATH_CLEAR_LOCKMODE(MyProc, f, lockmode);
result = true;
}
if (FAST_PATH_GET_BITS(MyProc, f) != 0)
++FastPathLocalUseCount;
}
return result;
}
| static void FinishStrongLockAcquire | ( | void | ) | [static] |
Definition at line 1514 of file lock.c.
Referenced by LockAcquireExtended().
{
StrongLockInProgress = NULL;
}
| VirtualTransactionId* GetLockConflicts | ( | const LOCKTAG * | locktag, | |
| LOCKMODE | lockmode | |||
| ) |
Definition at line 2619 of file lock.c.
References PROC_HDR::allProcCount, PROC_HDR::allProcs, PGPROC::backendLock, ConflictsWithRelationFastPath, LockMethodData::conflictTab, PGPROC::databaseId, elog, ERROR, FAST_PATH_GET_BITS, PGPROC::fpRelId, GET_VXID_FROM_PGPROC, hash_search_with_hash_value(), PROCLOCK::holdMask, i, InHotStandby, lengthof, LockHashPartitionLock, PROCLOCK::lockLink, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_SHARED, LWLockAcquire(), LWLockRelease(), MaxBackends, MemoryContextAlloc(), PROCLOCKTAG::myProc, MyProc, NULL, LockMethodData::numLockModes, offsetof, palloc0(), PANIC, ProcGlobal, LOCK::procLocks, SHMQueueNext(), PROCLOCK::tag, TopMemoryContext, VirtualTransactionIdEquals, and VirtualTransactionIdIsValid.
Referenced by DefineIndex(), index_drop(), and ResolveRecoveryConflictWithLock().
{
static VirtualTransactionId *vxids;
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
LOCK *lock;
LOCKMASK conflictMask;
SHM_QUEUE *procLocks;
PROCLOCK *proclock;
uint32 hashcode;
LWLockId partitionLock;
int count = 0;
int fast_count = 0;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
elog(ERROR, "unrecognized lock mode: %d", lockmode);
/*
* Allocate memory to store results, and fill with InvalidVXID. We only
* need enough space for MaxBackends + a terminator, since prepared xacts
* don't count. InHotStandby allocate once in TopMemoryContext.
*/
if (InHotStandby)
{
if (vxids == NULL)
vxids = (VirtualTransactionId *)
MemoryContextAlloc(TopMemoryContext,
sizeof(VirtualTransactionId) * (MaxBackends + 1));
}
else
vxids = (VirtualTransactionId *)
palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1));
/* Compute hash code and partiton lock, and look up conflicting modes. */
hashcode = LockTagHashCode(locktag);
partitionLock = LockHashPartitionLock(hashcode);
conflictMask = lockMethodTable->conflictTab[lockmode];
/*
* Fast path locks might not have been entered in the primary lock table.
* If the lock we're dealing with could conflict with such a lock, we must
* examine each backend's fast-path array for conflicts.
*/
if (ConflictsWithRelationFastPath(locktag, lockmode))
{
int i;
Oid relid = locktag->locktag_field2;
VirtualTransactionId vxid;
/*
* Iterate over relevant PGPROCs. Anything held by a prepared
* transaction will have been transferred to the primary lock table,
* so we need not worry about those. This is all a bit fuzzy, because
* new locks could be taken after we've visited a particular
* partition, but the callers had better be prepared to deal with that
* anyway, since the locks could equally well be taken between the
* time we return the value and the time the caller does something
* with it.
*/
for (i = 0; i < ProcGlobal->allProcCount; i++)
{
PGPROC *proc = &ProcGlobal->allProcs[i];
uint32 f;
/* A backend never blocks itself */
if (proc == MyProc)
continue;
LWLockAcquire(proc->backendLock, LW_SHARED);
/*
* If the target backend isn't referencing the same database as the
* lock, then we needn't examine the individual relation IDs at
* all; none of them can be relevant.
*
* See FastPathTransferLocks() for discussion of why we do this
* test after acquiring the lock.
*/
if (proc->databaseId != locktag->locktag_field1)
{
LWLockRelease(proc->backendLock);
continue;
}
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; f++)
{
uint32 lockmask;
/* Look for an allocated slot matching the given relid. */
if (relid != proc->fpRelId[f])
continue;
lockmask = FAST_PATH_GET_BITS(proc, f);
if (!lockmask)
continue;
lockmask <<= FAST_PATH_LOCKNUMBER_OFFSET;
/*
* There can only be one entry per relation, so if we found it
* and it doesn't conflict, we can skip the rest of the slots.
*/
if ((lockmask & conflictMask) == 0)
break;
/* Conflict! */
GET_VXID_FROM_PGPROC(vxid, *proc);
/*
* If we see an invalid VXID, then either the xact has already
* committed (or aborted), or it's a prepared xact. In either
* case we may ignore it.
*/
if (VirtualTransactionIdIsValid(vxid))
vxids[count++] = vxid;
break;
}
LWLockRelease(proc->backendLock);
}
}
/* Remember how many fast-path conflicts we found. */
fast_count = count;
/*
* Look up the lock object matching the tag.
*/
LWLockAcquire(partitionLock, LW_SHARED);
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(const void *) locktag,
hashcode,
HASH_FIND,
NULL);
if (!lock)
{
/*
* If the lock object doesn't exist, there is nothing holding a lock
* on this lockable object.
*/
LWLockRelease(partitionLock);
return vxids;
}
/*
* Examine each existing holder (or awaiter) of the lock.
*/
procLocks = &(lock->procLocks);
proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
offsetof(PROCLOCK, lockLink));
while (proclock)
{
if (conflictMask & proclock->holdMask)
{
PGPROC *proc = proclock->tag.myProc;
/* A backend never blocks itself */
if (proc != MyProc)
{
VirtualTransactionId vxid;
GET_VXID_FROM_PGPROC(vxid, *proc);
/*
* If we see an invalid VXID, then either the xact has already
* committed (or aborted), or it's a prepared xact. In either
* case we may ignore it.
*/
if (VirtualTransactionIdIsValid(vxid))
{
int i;
/* Avoid duplicate entries. */
for (i = 0; i < fast_count; ++i)
if (VirtualTransactionIdEquals(vxids[i], vxid))
break;
if (i >= fast_count)
vxids[count++] = vxid;
}
}
}
proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
offsetof(PROCLOCK, lockLink));
}
LWLockRelease(partitionLock);
if (count > MaxBackends) /* should never happen */
elog(PANIC, "too many conflicting locks found");
return vxids;
}
| const char* GetLockmodeName | ( | LOCKMETHODID | lockmethodid, | |
| LOCKMODE | mode | |||
| ) |
Definition at line 3486 of file lock.c.
References Assert, lengthof, and LockMethodData::lockModeNames.
Referenced by DeadLockReport(), pg_lock_status(), and ProcSleep().
{
Assert(lockmethodid > 0 && lockmethodid < lengthof(LockMethods));
Assert(mode > 0 && mode <= LockMethods[lockmethodid]->numLockModes);
return LockMethods[lockmethodid]->lockModeNames[mode];
}
| LockMethod GetLocksMethodTable | ( | const LOCK * | lock | ) |
Definition at line 461 of file lock.c.
References Assert, lengthof, and LOCK_LOCKMETHOD.
Referenced by DeadLockCheck(), and FindLockCycleRecurse().
{
LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*lock);
Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
return LockMethods[lockmethodid];
}
| LockData* GetLockStatusData | ( | void | ) |
Definition at line 3246 of file lock.c.
References PROC_HDR::allProcCount, PROC_HDR::allProcs, Assert, LockInstanceData::backend, VirtualTransactionId::backendId, PGPROC::backendId, PGPROC::backendLock, PGPROC::databaseId, ExclusiveLock, FAST_PATH_GET_BITS, LockInstanceData::fastpath, FirstLockMgrLock, PGPROC::fpLocalTransactionId, PGPROC::fpRelId, PGPROC::fpVXIDLock, hash_get_num_entries(), hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, LockInstanceData::holdMask, i, VirtualTransactionId::localTransactionId, LOCKBIT_ON, LockData::locks, LockInstanceData::locktag, LW_SHARED, LWLockAcquire(), LWLockRelease(), PGPROC::lxid, LockInstanceData::lxid, MaxBackends, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, LockData::nelements, palloc(), PGPROC::pid, LockInstanceData::pid, ProcGlobal, repalloc(), SET_LOCKTAG_RELATION, SET_LOCKTAG_VIRTUALTRANSACTION, LOCK::tag, PROCLOCK::tag, PGPROC::waitLock, PGPROC::waitLockMode, and LockInstanceData::waitLockMode.
Referenced by pg_lock_status().
{
LockData *data;
PROCLOCK *proclock;
HASH_SEQ_STATUS seqstat;
int els;
int el;
int i;
data = (LockData *) palloc(sizeof(LockData));
/* Guess how much space we'll need. */
els = MaxBackends;
el = 0;
data->locks = (LockInstanceData *) palloc(sizeof(LockInstanceData) * els);
/*
* First, we iterate through the per-backend fast-path arrays, locking
* them one at a time. This might produce an inconsistent picture of the
* system state, but taking all of those LWLocks at the same time seems
* impractical (in particular, note MAX_SIMUL_LWLOCKS). It shouldn't
* matter too much, because none of these locks can be involved in lock
* conflicts anyway - anything that might must be present in the main lock
* table.
*/
for (i = 0; i < ProcGlobal->allProcCount; ++i)
{
PGPROC *proc = &ProcGlobal->allProcs[i];
uint32 f;
LWLockAcquire(proc->backendLock, LW_SHARED);
for (f = 0; f < FP_LOCK_SLOTS_PER_BACKEND; ++f)
{
LockInstanceData *instance;
uint32 lockbits = FAST_PATH_GET_BITS(proc, f);
/* Skip unallocated slots. */
if (!lockbits)
continue;
if (el >= els)
{
els += MaxBackends;
data->locks = (LockInstanceData *)
repalloc(data->locks, sizeof(LockInstanceData) * els);
}
instance = &data->locks[el];
SET_LOCKTAG_RELATION(instance->locktag, proc->databaseId,
proc->fpRelId[f]);
instance->holdMask = lockbits << FAST_PATH_LOCKNUMBER_OFFSET;
instance->waitLockMode = NoLock;
instance->backend = proc->backendId;
instance->lxid = proc->lxid;
instance->pid = proc->pid;
instance->fastpath = true;
el++;
}
if (proc->fpVXIDLock)
{
VirtualTransactionId vxid;
LockInstanceData *instance;
if (el >= els)
{
els += MaxBackends;
data->locks = (LockInstanceData *)
repalloc(data->locks, sizeof(LockInstanceData) * els);
}
vxid.backendId = proc->backendId;
vxid.localTransactionId = proc->fpLocalTransactionId;
instance = &data->locks[el];
SET_LOCKTAG_VIRTUALTRANSACTION(instance->locktag, vxid);
instance->holdMask = LOCKBIT_ON(ExclusiveLock);
instance->waitLockMode = NoLock;
instance->backend = proc->backendId;
instance->lxid = proc->lxid;
instance->pid = proc->pid;
instance->fastpath = true;
el++;
}
LWLockRelease(proc->backendLock);
}
/*
* Next, acquire lock on the entire shared lock data structure. We do
* this so that, at least for locks in the primary lock table, the state
* will be self-consistent.
*
* Since this is a read-only operation, we take shared instead of
* exclusive lock. There's not a whole lot of point to this, because all
* the normal operations require exclusive lock, but it doesn't hurt
* anything either. It will at least allow two backends to do
* GetLockStatusData in parallel.
*
* Must grab LWLocks in partition-number order to avoid LWLock deadlock.
*/
for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
LWLockAcquire(FirstLockMgrLock + i, LW_SHARED);
/* Now we can safely count the number of proclocks */
data->nelements = el + hash_get_num_entries(LockMethodProcLockHash);
if (data->nelements > els)
{
els = data->nelements;
data->locks = (LockInstanceData *)
repalloc(data->locks, sizeof(LockInstanceData) * els);
}
/* Now scan the tables to copy the data */
hash_seq_init(&seqstat, LockMethodProcLockHash);
while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
{
PGPROC *proc = proclock->tag.myProc;
LOCK *lock = proclock->tag.myLock;
LockInstanceData *instance = &data->locks[el];
memcpy(&instance->locktag, &lock->tag, sizeof(LOCKTAG));
instance->holdMask = proclock->holdMask;
if (proc->waitLock == proclock->tag.myLock)
instance->waitLockMode = proc->waitLockMode;
else
instance->waitLockMode = NoLock;
instance->backend = proc->backendId;
instance->lxid = proc->lxid;
instance->pid = proc->pid;
instance->fastpath = false;
el++;
}
/*
* And release locks. We do this in reverse order for two reasons: (1)
* Anyone else who needs more than one of the locks will be trying to lock
* them in increasing order; we don't want to release the other process
* until it can get all the locks it needs. (2) This avoids O(N^2)
* behavior inside LWLockRelease.
*/
for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
LWLockRelease(FirstLockMgrLock + i);
Assert(el == data->nelements);
return data;
}
| xl_standby_lock* GetRunningTransactionLocks | ( | int * | nlocks | ) |
Definition at line 3405 of file lock.c.
References AccessExclusiveLock, PROC_HDR::allPgXact, xl_standby_lock::dbOid, FirstLockMgrLock, hash_get_num_entries(), hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, i, LOCKBIT_ON, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG_RELATION, LOCKTAG::locktag_type, LW_SHARED, LWLockAcquire(), LWLockRelease(), PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, palloc(), PGPROC::pgprocno, ProcGlobal, xl_standby_lock::relOid, LOCK::tag, PROCLOCK::tag, TransactionIdIsValid, xl_standby_lock::xid, and PGXACT::xid.
Referenced by LogStandbySnapshot().
{
PROCLOCK *proclock;
HASH_SEQ_STATUS seqstat;
int i;
int index;
int els;
xl_standby_lock *accessExclusiveLocks;
/*
* Acquire lock on the entire shared lock data structure.
*
* Must grab LWLocks in partition-number order to avoid LWLock deadlock.
*/
for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
LWLockAcquire(FirstLockMgrLock + i, LW_SHARED);
/* Now we can safely count the number of proclocks */
els = hash_get_num_entries(LockMethodProcLockHash);
/*
* Allocating enough space for all locks in the lock table is overkill,
* but it's more convenient and faster than having to enlarge the array.
*/
accessExclusiveLocks = palloc(els * sizeof(xl_standby_lock));
/* Now scan the tables to copy the data */
hash_seq_init(&seqstat, LockMethodProcLockHash);
/*
* If lock is a currently granted AccessExclusiveLock then it will have
* just one proclock holder, so locks are never accessed twice in this
* particular case. Don't copy this code for use elsewhere because in the
* general case this will give you duplicate locks when looking at
* non-exclusive lock types.
*/
index = 0;
while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
{
/* make sure this definition matches the one used in LockAcquire */
if ((proclock->holdMask & LOCKBIT_ON(AccessExclusiveLock)) &&
proclock->tag.myLock->tag.locktag_type == LOCKTAG_RELATION)
{
PGPROC *proc = proclock->tag.myProc;
PGXACT *pgxact = &ProcGlobal->allPgXact[proc->pgprocno];
LOCK *lock = proclock->tag.myLock;
TransactionId xid = pgxact->xid;
/*
* Don't record locks for transactions if we know they have
* already issued their WAL record for commit but not yet released
* lock. It is still possible that we see locks held by already
* complete transactions, if they haven't yet zeroed their xids.
*/
if (!TransactionIdIsValid(xid))
continue;
accessExclusiveLocks[index].xid = xid;
accessExclusiveLocks[index].dbOid = lock->tag.locktag_field1;
accessExclusiveLocks[index].relOid = lock->tag.locktag_field2;
index++;
}
}
/*
* And release locks. We do this in reverse order for two reasons: (1)
* Anyone else who needs more than one of the locks will be trying to lock
* them in increasing order; we don't want to release the other process
* until it can get all the locks it needs. (2) This avoids O(N^2)
* behavior inside LWLockRelease.
*/
for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
LWLockRelease(FirstLockMgrLock + i);
*nlocks = index;
return accessExclusiveLocks;
}
| void GrantAwaitedLock | ( | void | ) |
Definition at line 1552 of file lock.c.
References GrantLockLocal().
Referenced by LockErrorCleanup(), and ProcSleep().
Definition at line 1325 of file lock.c.
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().
{
lock->nGranted++;
lock->granted[lockmode]++;
lock->grantMask |= LOCKBIT_ON(lockmode);
if (lock->granted[lockmode] == lock->requested[lockmode])
lock->waitMask &= LOCKBIT_OFF(lockmode);
proclock->holdMask |= LOCKBIT_ON(lockmode);
LOCK_PRINT("GrantLock", lock, lockmode);
Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
Assert(lock->nGranted <= lock->nRequested);
}
| static void GrantLockLocal | ( | LOCALLOCK * | locallock, | |
| ResourceOwner | owner | |||
| ) | [static] |
Definition at line 1459 of file lock.c.
References Assert, i, LOCALLOCK::lockOwners, LOCALLOCK::maxLockOwners, LOCALLOCKOWNER::nLocks, LOCALLOCK::nLocks, NULL, LOCALLOCK::numLockOwners, LOCALLOCKOWNER::owner, and ResourceOwnerRememberLock().
Referenced by GrantAwaitedLock(), and LockAcquireExtended().
{
LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
int i;
Assert(locallock->numLockOwners < locallock->maxLockOwners);
/* Count the total */
locallock->nLocks++;
/* Count the per-owner lock */
for (i = 0; i < locallock->numLockOwners; i++)
{
if (lockOwners[i].owner == owner)
{
lockOwners[i].nLocks++;
return;
}
}
lockOwners[i].owner = owner;
lockOwners[i].nLocks = 1;
locallock->numLockOwners++;
if (owner != NULL)
ResourceOwnerRememberLock(owner, locallock);
}
| void InitLocks | ( | void | ) |
Definition at line 372 of file lock.c.
References HASHCTL::entrysize, HASHCTL::hash, hash_create(), hash_destroy(), HASH_ELEM, HASH_FUNCTION, HASHCTL::keysize, MemSet, FastPathStrongRelationLockData::mutex, NLOCKENTS, HASHCTL::num_partitions, ShmemInitHash(), ShmemInitStruct(), and SpinLockInit.
Referenced by CreateSharedMemoryAndSemaphores().
{
HASHCTL info;
int hash_flags;
long init_table_size,
max_table_size;
bool found;
/*
* Compute init/max size to request for lock hashtables. Note these
* calculations must agree with LockShmemSize!
*/
max_table_size = NLOCKENTS();
init_table_size = max_table_size / 2;
/*
* Allocate hash table for LOCK structs. This stores per-locked-object
* information.
*/
MemSet(&info, 0, sizeof(info));
info.keysize = sizeof(LOCKTAG);
info.entrysize = sizeof(LOCK);
info.hash = tag_hash;
info.num_partitions = NUM_LOCK_PARTITIONS;
hash_flags = (HASH_ELEM | HASH_FUNCTION | HASH_PARTITION);
LockMethodLockHash = ShmemInitHash("LOCK hash",
init_table_size,
max_table_size,
&info,
hash_flags);
/* Assume an average of 2 holders per lock */
max_table_size *= 2;
init_table_size *= 2;
/*
* Allocate hash table for PROCLOCK structs. This stores
* per-lock-per-holder information.
*/
info.keysize = sizeof(PROCLOCKTAG);
info.entrysize = sizeof(PROCLOCK);
info.hash = proclock_hash;
info.num_partitions = NUM_LOCK_PARTITIONS;
hash_flags = (HASH_ELEM | HASH_FUNCTION | HASH_PARTITION);
LockMethodProcLockHash = ShmemInitHash("PROCLOCK hash",
init_table_size,
max_table_size,
&info,
hash_flags);
/*
* Allocate fast-path structures.
*/
FastPathStrongRelationLocks =
ShmemInitStruct("Fast Path Strong Relation Lock Data",
sizeof(FastPathStrongRelationLockData), &found);
if (!found)
SpinLockInit(&FastPathStrongRelationLocks->mutex);
/*
* Allocate non-shared hash table for LOCALLOCK structs. This stores lock
* counts and resource owner information.
*
* The non-shared table could already exist in this process (this occurs
* when the postmaster is recreating shared memory after a backend crash).
* If so, delete and recreate it. (We could simply leave it, since it
* ought to be empty in the postmaster, but for safety let's zap it.)
*/
if (LockMethodLocalHash)
hash_destroy(LockMethodLocalHash);
info.keysize = sizeof(LOCALLOCKTAG);
info.entrysize = sizeof(LOCALLOCK);
info.hash = tag_hash;
hash_flags = (HASH_ELEM | HASH_FUNCTION);
LockMethodLocalHash = hash_create("LOCALLOCK hash",
16,
&info,
hash_flags);
}
| void lock_twophase_postabort | ( | TransactionId | xid, | |
| uint16 | info, | |||
| void * | recdata, | |||
| uint32 | len | |||
| ) |
Definition at line 3836 of file lock.c.
References lock_twophase_postcommit().
{
lock_twophase_postcommit(xid, info, recdata, len);
}
| void lock_twophase_postcommit | ( | TransactionId | xid, | |
| uint16 | info, | |||
| void * | recdata, | |||
| uint32 | len | |||
| ) |
Definition at line 3810 of file lock.c.
References Assert, elog, ERROR, lengthof, TwoPhaseLockRecord::lockmode, LockRefindAndRelease(), TwoPhaseLockRecord::locktag, LOCKTAG::locktag_lockmethodid, and TwoPhaseGetDummyProc().
Referenced by lock_twophase_postabort().
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
PGPROC *proc = TwoPhaseGetDummyProc(xid);
LOCKTAG *locktag;
LOCKMETHODID lockmethodid;
LockMethod lockMethodTable;
Assert(len == sizeof(TwoPhaseLockRecord));
locktag = &rec->locktag;
lockmethodid = locktag->locktag_lockmethodid;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
LockRefindAndRelease(lockMethodTable, proc, locktag, rec->lockmode, true);
}
| void lock_twophase_recover | ( | TransactionId | xid, | |
| uint16 | info, | |||
| void * | recdata, | |||
| uint32 | len | |||
| ) |
Definition at line 3599 of file lock.c.
References Assert, ConflictsWithRelationFastPath, FastPathStrongRelationLockData::count, elog, ereport, errcode(), errhint(), errmsg(), ERROR, FastPathStrongLockHashPartition, LOCK::granted, GrantLock(), LOCK::grantMask, HASH_REMOVE, hash_search_with_hash_value(), PROCLOCK::holdMask, lengthof, LOCK_PRINT, LOCKBIT_ON, LockHashPartition, LockHashPartitionLock, PROCLOCK::lockLink, TwoPhaseLockRecord::lockmode, LockMethodData::lockModeNames, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_lockmethodid, LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MAX_LOCKMODES, MemSet, FastPathStrongRelationLockData::mutex, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, PGPROC::myProcLocks, LOCK::nGranted, LOCK::nRequested, NULL, PANIC, PROCLOCK::procLink, PROCLOCK_PRINT, ProcLockHashCode(), LOCK::procLocks, ProcQueueInit(), PROCLOCK::releaseMask, LOCK::requested, SHMQueueEmpty(), SHMQueueInit(), SHMQueueInsertBefore(), SpinLockAcquire, SpinLockRelease, LOCK::tag, TwoPhaseGetDummyProc(), LOCK::waitMask, and LOCK::waitProcs.
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
PGPROC *proc = TwoPhaseGetDummyProc(xid);
LOCKTAG *locktag;
LOCKMODE lockmode;
LOCKMETHODID lockmethodid;
LOCK *lock;
PROCLOCK *proclock;
PROCLOCKTAG proclocktag;
bool found;
uint32 hashcode;
uint32 proclock_hashcode;
int partition;
LWLockId partitionLock;
LockMethod lockMethodTable;
Assert(len == sizeof(TwoPhaseLockRecord));
locktag = &rec->locktag;
lockmode = rec->lockmode;
lockmethodid = locktag->locktag_lockmethodid;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
hashcode = LockTagHashCode(locktag);
partition = LockHashPartition(hashcode);
partitionLock = LockHashPartitionLock(hashcode);
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
* Find or create a lock with this tag.
*/
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(void *) locktag,
hashcode,
HASH_ENTER_NULL,
&found);
if (!lock)
{
LWLockRelease(partitionLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
}
/*
* if it's a new lock object, initialize it
*/
if (!found)
{
lock->grantMask = 0;
lock->waitMask = 0;
SHMQueueInit(&(lock->procLocks));
ProcQueueInit(&(lock->waitProcs));
lock->nRequested = 0;
lock->nGranted = 0;
MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
LOCK_PRINT("lock_twophase_recover: new", lock, lockmode);
}
else
{
LOCK_PRINT("lock_twophase_recover: found", lock, lockmode);
Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
Assert(lock->nGranted <= lock->nRequested);
}
/*
* Create the hash key for the proclock table.
*/
proclocktag.myLock = lock;
proclocktag.myProc = proc;
proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
/*
* Find or create a proclock entry with this tag
*/
proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &proclocktag,
proclock_hashcode,
HASH_ENTER_NULL,
&found);
if (!proclock)
{
/* Ooops, not enough shmem for the proclock */
if (lock->nRequested == 0)
{
/*
* There are no other requestors of this lock, so garbage-collect
* the lock object. We *must* do this to avoid a permanent leak
* of shared memory, because there won't be anything to cause
* anyone to release the lock object later.
*/
Assert(SHMQueueEmpty(&(lock->procLocks)));
if (!hash_search_with_hash_value(LockMethodLockHash,
(void *) &(lock->tag),
hashcode,
HASH_REMOVE,
NULL))
elog(PANIC, "lock table corrupted");
}
LWLockRelease(partitionLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
}
/*
* If new, initialize the new entry
*/
if (!found)
{
proclock->holdMask = 0;
proclock->releaseMask = 0;
/* Add proclock to appropriate lists */
SHMQueueInsertBefore(&lock->procLocks, &proclock->lockLink);
SHMQueueInsertBefore(&(proc->myProcLocks[partition]),
&proclock->procLink);
PROCLOCK_PRINT("lock_twophase_recover: new", proclock);
}
else
{
PROCLOCK_PRINT("lock_twophase_recover: found", proclock);
Assert((proclock->holdMask & ~lock->grantMask) == 0);
}
/*
* lock->nRequested and lock->requested[] count the total number of
* requests, whether granted or waiting, so increment those immediately.
*/
lock->nRequested++;
lock->requested[lockmode]++;
Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
/*
* We shouldn't already hold the desired lock.
*/
if (proclock->holdMask & LOCKBIT_ON(lockmode))
elog(ERROR, "lock %s on object %u/%u/%u is already held",
lockMethodTable->lockModeNames[lockmode],
lock->tag.locktag_field1, lock->tag.locktag_field2,
lock->tag.locktag_field3);
/*
* We ignore any possible conflicts and just grant ourselves the lock. Not
* only because we don't bother, but also to avoid deadlocks when
* switching from standby to normal mode. See function comment.
*/
GrantLock(lock, proclock, lockmode);
/*
* Bump strong lock count, to make sure any fast-path lock requests won't
* be granted without consulting the primary lock table.
*/
if (ConflictsWithRelationFastPath(&lock->tag, lockmode))
{
uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
FastPathStrongRelationLocks->count[fasthashcode]++;
SpinLockRelease(&FastPathStrongRelationLocks->mutex);
}
LWLockRelease(partitionLock);
}
| void lock_twophase_standby_recover | ( | TransactionId | xid, | |
| uint16 | info, | |||
| void * | recdata, | |||
| uint32 | len | |||
| ) |
Definition at line 3778 of file lock.c.
References AccessExclusiveLock, Assert, elog, ERROR, lengthof, TwoPhaseLockRecord::lockmode, TwoPhaseLockRecord::locktag, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LOCKTAG_RELATION, LOCKTAG::locktag_type, and StandbyAcquireAccessExclusiveLock().
{
TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
LOCKTAG *locktag;
LOCKMODE lockmode;
LOCKMETHODID lockmethodid;
Assert(len == sizeof(TwoPhaseLockRecord));
locktag = &rec->locktag;
lockmode = rec->lockmode;
lockmethodid = locktag->locktag_lockmethodid;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
if (lockmode == AccessExclusiveLock &&
locktag->locktag_type == LOCKTAG_RELATION)
{
StandbyAcquireAccessExclusiveLock(xid,
locktag->locktag_field1 /* dboid */ ,
locktag->locktag_field2 /* reloid */ );
}
}
| LockAcquireResult LockAcquire | ( | const LOCKTAG * | locktag, | |
| LOCKMODE | lockmode, | |||
| bool | sessionLock, | |||
| bool | dontWait | |||
| ) |
Definition at line 672 of file lock.c.
References LockAcquireExtended().
Referenced by ConditionalLockPage(), ConditionalLockRelation(), ConditionalLockRelationOid(), ConditionalLockTuple(), ConditionalXactLockTableWait(), LockDatabaseObject(), LockPage(), LockRelation(), LockRelationForExtension(), LockRelationIdForSession(), LockRelationOid(), LockSharedObject(), LockSharedObjectForSession(), LockTuple(), pg_advisory_lock_int4(), pg_advisory_lock_int8(), pg_advisory_lock_shared_int4(), pg_advisory_lock_shared_int8(), pg_advisory_xact_lock_int4(), pg_advisory_xact_lock_int8(), pg_advisory_xact_lock_shared_int4(), pg_advisory_xact_lock_shared_int8(), pg_try_advisory_lock_int4(), pg_try_advisory_lock_int8(), pg_try_advisory_lock_shared_int4(), pg_try_advisory_lock_shared_int8(), pg_try_advisory_xact_lock_int4(), pg_try_advisory_xact_lock_int8(), pg_try_advisory_xact_lock_shared_int4(), pg_try_advisory_xact_lock_shared_int8(), VirtualXactLock(), XactLockTableInsert(), and XactLockTableWait().
{
return LockAcquireExtended(locktag, lockmode, sessionLock, dontWait, true);
}
| LockAcquireResult LockAcquireExtended | ( | const LOCKTAG * | locktag, | |
| LOCKMODE | lockmode, | |||
| bool | sessionLock, | |||
| bool | dontWait, | |||
| bool | reportMemoryError | |||
| ) |
Definition at line 690 of file lock.c.
References AbortStrongLockAcquire(), AccessExclusiveLock, Assert, PGPROC::backendLock, BeginStrongLockAcquire(), ConflictsWithRelationFastPath, LockMethodData::conflictTab, FastPathStrongRelationLockData::count, CurrentResourceOwner, EligibleForRelationFastPath, elog, ereport, errcode(), errhint(), errmsg(), ERROR, FastPathGrantRelationLock(), FastPathLocalUseCount, FastPathStrongLockHashPartition, FastPathTransferRelationLocks(), FinishStrongLockAcquire(), FP_LOCK_SLOTS_PER_BACKEND, GrantLock(), GrantLockLocal(), HASH_REMOVE, hash_search(), hash_search_with_hash_value(), LOCALLOCK::hashcode, PGPROC::heldLocks, PROCLOCK::holdMask, LOCALLOCK::holdsStrongLockCount, InRecovery, lengthof, LOCALLOCK::lock, LOCALLOCKTAG::lock, LOCK_PRINT, LOCKBIT_ON, LockCheckConflicts(), LockHashPartitionLock, PROCLOCK::lockLink, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_field4, LOCKTAG::locktag_lockmethodid, LOCKTAG_OBJECT, LOCKTAG_RELATION, LOCKTAG::locktag_type, LockTagHashCode(), LOG, LogAccessExclusiveLock(), LogAccessExclusiveLockPrepare(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCK::maxLockOwners, MemoryContextAlloc(), MemSet, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, MyProc, LOCK::nGranted, LOCALLOCK::nLocks, LOCK::nRequested, NULL, LockMethodData::numLockModes, LOCALLOCK::numLockOwners, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, ProcLockHashCode(), RecoveryInProgress(), RemoveLocalLock(), repalloc(), LOCK::requested, RowExclusiveLock, SetupLockInTable(), SHMQueueDelete(), STATUS_FOUND, STATUS_OK, PROCLOCK::tag, TopMemoryContext, LOCK::waitMask, WaitOnLock(), and XLogStandbyInfoActive.
Referenced by LockAcquire(), ResolveRecoveryConflictWithLock(), and StandbyAcquireAccessExclusiveLock().
{
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
LOCALLOCKTAG localtag;
LOCALLOCK *locallock;
LOCK *lock;
PROCLOCK *proclock;
bool found;
ResourceOwner owner;
uint32 hashcode;
LWLockId partitionLock;
int status;
bool log_lock = false;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
elog(ERROR, "unrecognized lock mode: %d", lockmode);
if (RecoveryInProgress() && !InRecovery &&
(locktag->locktag_type == LOCKTAG_OBJECT ||
locktag->locktag_type == LOCKTAG_RELATION) &&
lockmode > RowExclusiveLock)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot acquire lock mode %s on database objects while recovery is in progress",
lockMethodTable->lockModeNames[lockmode]),
errhint("Only RowExclusiveLock or less can be acquired on database objects during recovery.")));
#ifdef LOCK_DEBUG
if (LOCK_DEBUG_ENABLED(locktag))
elog(LOG, "LockAcquire: lock [%u,%u] %s",
locktag->locktag_field1, locktag->locktag_field2,
lockMethodTable->lockModeNames[lockmode]);
#endif
/* Identify owner for lock */
if (sessionLock)
owner = NULL;
else
owner = CurrentResourceOwner;
/*
* Find or create a LOCALLOCK entry for this lock and lockmode
*/
MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
localtag.lock = *locktag;
localtag.mode = lockmode;
locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
(void *) &localtag,
HASH_ENTER, &found);
/*
* if it's a new locallock object, initialize it
*/
if (!found)
{
locallock->lock = NULL;
locallock->proclock = NULL;
locallock->hashcode = LockTagHashCode(&(localtag.lock));
locallock->nLocks = 0;
locallock->numLockOwners = 0;
locallock->maxLockOwners = 8;
locallock->holdsStrongLockCount = FALSE;
locallock->lockOwners = NULL;
locallock->lockOwners = (LOCALLOCKOWNER *)
MemoryContextAlloc(TopMemoryContext,
locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
}
else
{
/* Make sure there will be room to remember the lock */
if (locallock->numLockOwners >= locallock->maxLockOwners)
{
int newsize = locallock->maxLockOwners * 2;
locallock->lockOwners = (LOCALLOCKOWNER *)
repalloc(locallock->lockOwners,
newsize * sizeof(LOCALLOCKOWNER));
locallock->maxLockOwners = newsize;
}
}
hashcode = locallock->hashcode;
/*
* If we already hold the lock, we can just increase the count locally.
*/
if (locallock->nLocks > 0)
{
GrantLockLocal(locallock, owner);
return LOCKACQUIRE_ALREADY_HELD;
}
/*
* Emit a WAL record if acquisition of this lock needs to be replayed in a
* standby server. Only AccessExclusiveLocks can conflict with lock types
* that read-only transactions can acquire in a standby server.
*
* Make sure this definition matches the one in
* GetRunningTransactionLocks().
*
* First we prepare to log, then after lock acquired we issue log record.
*/
if (lockmode >= AccessExclusiveLock &&
locktag->locktag_type == LOCKTAG_RELATION &&
!RecoveryInProgress() &&
XLogStandbyInfoActive())
{
LogAccessExclusiveLockPrepare();
log_lock = true;
}
/*
* Attempt to take lock via fast path, if eligible. But if we remember
* having filled up the fast path array, we don't attempt to make any
* further use of it until we release some locks. It's possible that some
* other backend has transferred some of those locks to the shared hash
* table, leaving space free, but it's not worth acquiring the LWLock just
* to check. It's also possible that we're acquiring a second or third
* lock type on a relation we have already locked using the fast-path, but
* for now we don't worry about that case either.
*/
if (EligibleForRelationFastPath(locktag, lockmode)
&& FastPathLocalUseCount < FP_LOCK_SLOTS_PER_BACKEND)
{
uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
bool acquired;
/*
* LWLockAcquire acts as a memory sequencing point, so it's safe to
* assume that any strong locker whose increment to
* FastPathStrongRelationLocks->counts becomes visible after we test
* it has yet to begin to transfer fast-path locks.
*/
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
acquired = false;
else
acquired = FastPathGrantRelationLock(locktag->locktag_field2,
lockmode);
LWLockRelease(MyProc->backendLock);
if (acquired)
{
GrantLockLocal(locallock, owner);
return LOCKACQUIRE_OK;
}
}
/*
* If this lock could potentially have been taken via the fast-path by
* some other backend, we must (temporarily) disable further use of the
* fast-path for this lock tag, and migrate any locks already taken via
* this method to the main lock table.
*/
if (ConflictsWithRelationFastPath(locktag, lockmode))
{
uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
BeginStrongLockAcquire(locallock, fasthashcode);
if (!FastPathTransferRelationLocks(lockMethodTable, locktag,
hashcode))
{
AbortStrongLockAcquire();
if (reportMemoryError)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
else
return LOCKACQUIRE_NOT_AVAIL;
}
}
/*
* We didn't find the lock in our LOCALLOCK table, and we didn't manage to
* take it via the fast-path, either, so we've got to mess with the shared
* lock table.
*/
partitionLock = LockHashPartitionLock(hashcode);
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
* Find or create a proclock entry with this tag
*/
proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
hashcode, lockmode);
if (!proclock)
{
AbortStrongLockAcquire();
LWLockRelease(partitionLock);
if (reportMemoryError)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
else
return LOCKACQUIRE_NOT_AVAIL;
}
locallock->proclock = proclock;
lock = proclock->tag.myLock;
locallock->lock = lock;
/*
* If lock requested conflicts with locks requested by waiters, must join
* wait queue. Otherwise, check for conflict with already-held locks.
* (That's last because most complex check.)
*/
if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
status = STATUS_FOUND;
else
status = LockCheckConflicts(lockMethodTable, lockmode,
lock, proclock, MyProc);
if (status == STATUS_OK)
{
/* No conflict with held or previously requested locks */
GrantLock(lock, proclock, lockmode);
GrantLockLocal(locallock, owner);
}
else
{
Assert(status == STATUS_FOUND);
/*
* We can't acquire the lock immediately. If caller specified no
* blocking, remove useless table entries and return NOT_AVAIL without
* waiting.
*/
if (dontWait)
{
AbortStrongLockAcquire();
if (proclock->holdMask == 0)
{
uint32 proclock_hashcode;
proclock_hashcode = ProcLockHashCode(&proclock->tag, hashcode);
SHMQueueDelete(&proclock->lockLink);
SHMQueueDelete(&proclock->procLink);
if (!hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &(proclock->tag),
proclock_hashcode,
HASH_REMOVE,
NULL))
elog(PANIC, "proclock table corrupted");
}
else
PROCLOCK_PRINT("LockAcquire: NOWAIT", proclock);
lock->nRequested--;
lock->requested[lockmode]--;
LOCK_PRINT("LockAcquire: conditional lock failed", lock, lockmode);
Assert((lock->nRequested > 0) && (lock->requested[lockmode] >= 0));
Assert(lock->nGranted <= lock->nRequested);
LWLockRelease(partitionLock);
if (locallock->nLocks == 0)
RemoveLocalLock(locallock);
return LOCKACQUIRE_NOT_AVAIL;
}
/*
* Set bitmask of locks this process already holds on this object.
*/
MyProc->heldLocks = proclock->holdMask;
/*
* Sleep till someone wakes me up.
*/
TRACE_POSTGRESQL_LOCK_WAIT_START(locktag->locktag_field1,
locktag->locktag_field2,
locktag->locktag_field3,
locktag->locktag_field4,
locktag->locktag_type,
lockmode);
WaitOnLock(locallock, owner);
TRACE_POSTGRESQL_LOCK_WAIT_DONE(locktag->locktag_field1,
locktag->locktag_field2,
locktag->locktag_field3,
locktag->locktag_field4,
locktag->locktag_type,
lockmode);
/*
* NOTE: do not do any material change of state between here and
* return. All required changes in locktable state must have been
* done when the lock was granted to us --- see notes in WaitOnLock.
*/
/*
* Check the proclock entry status, in case something in the ipc
* communication doesn't work correctly.
*/
if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
{
AbortStrongLockAcquire();
PROCLOCK_PRINT("LockAcquire: INCONSISTENT", proclock);
LOCK_PRINT("LockAcquire: INCONSISTENT", lock, lockmode);
/* Should we retry ? */
LWLockRelease(partitionLock);
elog(ERROR, "LockAcquire failed");
}
PROCLOCK_PRINT("LockAcquire: granted", proclock);
LOCK_PRINT("LockAcquire: granted", lock, lockmode);
}
/*
* Lock state is fully up-to-date now; if we error out after this, no
* special error cleanup is required.
*/
FinishStrongLockAcquire();
LWLockRelease(partitionLock);
/*
* Emit a WAL record if acquisition of this lock need to be replayed in a
* standby server.
*/
if (log_lock)
{
/*
* Decode the locktag back to the original values, to avoid sending
* lots of empty bytes with every message. See lock.h to check how a
* locktag is defined for LOCKTAG_RELATION
*/
LogAccessExclusiveLock(locktag->locktag_field1,
locktag->locktag_field2);
}
return LOCKACQUIRE_OK;
}
| int LockCheckConflicts | ( | LockMethod | lockMethodTable, | |
| LOCKMODE | lockmode, | |||
| LOCK * | lock, | |||
| PROCLOCK * | proclock, | |||
| PGPROC * | proc | |||
| ) |
Definition at line 1256 of file lock.c.
References LockMethodData::conflictTab, LOCK::granted, LOCK::grantMask, PROCLOCK::holdMask, i, LOCKBIT_ON, LockMethodData::numLockModes, and PROCLOCK_PRINT.
Referenced by LockAcquireExtended(), ProcLockWakeup(), and ProcSleep().
{
int numLockModes = lockMethodTable->numLockModes;
LOCKMASK myLocks;
LOCKMASK otherLocks;
int i;
/*
* first check for global conflicts: If no locks conflict with my request,
* then I get the lock.
*
* Checking for conflict: lock->grantMask represents the types of
* currently held locks. conflictTable[lockmode] has a bit set for each
* type of lock that conflicts with request. Bitwise compare tells if
* there is a conflict.
*/
if (!(lockMethodTable->conflictTab[lockmode] & lock->grantMask))
{
PROCLOCK_PRINT("LockCheckConflicts: no conflict", proclock);
return STATUS_OK;
}
/*
* Rats. Something conflicts. But it could still be my own lock. We have
* to construct a conflict mask that does not reflect our own locks, but
* only lock types held by other processes.
*/
myLocks = proclock->holdMask;
otherLocks = 0;
for (i = 1; i <= numLockModes; i++)
{
int myHolding = (myLocks & LOCKBIT_ON(i)) ? 1 : 0;
if (lock->granted[i] > myHolding)
otherLocks |= LOCKBIT_ON(i);
}
/*
* now check again for conflicts. 'otherLocks' describes the types of
* locks held by other processes. If one of these conflicts with the kind
* of lock that I want, there is a conflict and I have to sleep.
*/
if (!(lockMethodTable->conflictTab[lockmode] & otherLocks))
{
/* no conflict. OK to get the lock */
PROCLOCK_PRINT("LockCheckConflicts: resolved", proclock);
return STATUS_OK;
}
PROCLOCK_PRINT("LockCheckConflicts: conflicting", proclock);
return STATUS_FOUND;
}
Definition at line 560 of file lock.c.
References LockMethodData::conflictTab, elog, ERROR, hash_search(), LOCALLOCK::hashcode, PROCLOCK::holdMask, lengthof, LOCALLOCK::lock, LOCALLOCKTAG::lock, LOCK_PRINT, LOCKBIT_ON, LockHashPartitionLock, 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().
{
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
LOCALLOCKTAG localtag;
LOCALLOCK *locallock;
LOCK *lock;
PROCLOCK *proclock;
LWLockId partitionLock;
bool hasWaiters = false;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
elog(ERROR, "unrecognized lock mode: %d", lockmode);
#ifdef LOCK_DEBUG
if (LOCK_DEBUG_ENABLED(locktag))
elog(LOG, "LockHasWaiters: lock [%u,%u] %s",
locktag->locktag_field1, locktag->locktag_field2,
lockMethodTable->lockModeNames[lockmode]);
#endif
/*
* Find the LOCALLOCK entry for this lock and lockmode
*/
MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
localtag.lock = *locktag;
localtag.mode = lockmode;
locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
(void *) &localtag,
HASH_FIND, NULL);
/*
* let the caller print its own error message, too. Do not ereport(ERROR).
*/
if (!locallock || locallock->nLocks <= 0)
{
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
return false;
}
/*
* Check the shared lock table.
*/
partitionLock = LockHashPartitionLock(locallock->hashcode);
LWLockAcquire(partitionLock, LW_SHARED);
/*
* We don't need to re-find the lock or proclock, since we kept their
* addresses in the locallock table, and they couldn't have been removed
* while we were holding a lock on them.
*/
lock = locallock->lock;
LOCK_PRINT("LockHasWaiters: found", lock, lockmode);
proclock = locallock->proclock;
PROCLOCK_PRINT("LockHasWaiters: found", proclock);
/*
* Double-check that we are actually holding a lock of the type we want to
* release.
*/
if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
{
PROCLOCK_PRINT("LockHasWaiters: WRONGTYPE", proclock);
LWLockRelease(partitionLock);
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
RemoveLocalLock(locallock);
return false;
}
/*
* Do the checking.
*/
if ((lockMethodTable->conflictTab[lockmode] & lock->waitMask) != 0)
hasWaiters = true;
LWLockRelease(partitionLock);
return hasWaiters;
}
| void LockReassignCurrentOwner | ( | LOCALLOCK ** | locallocks, | |
| int | nlocks | |||
| ) |
Definition at line 2298 of file lock.c.
References Assert, CurrentResourceOwner, hash_seq_init(), hash_seq_search(), i, LockReassignOwner(), NULL, and ResourceOwnerGetParent().
Referenced by ResourceOwnerReleaseInternal().
{
ResourceOwner parent = ResourceOwnerGetParent(CurrentResourceOwner);
Assert(parent != NULL);
if (locallocks == NULL)
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
LockReassignOwner(locallock, parent);
}
else
{
int i;
for (i = nlocks - 1; i >= 0; i--)
LockReassignOwner(locallocks[i], parent);
}
}
| static void LockReassignOwner | ( | LOCALLOCK * | locallock, | |
| ResourceOwner | parent | |||
| ) | [static] |
Definition at line 2328 of file lock.c.
References CurrentResourceOwner, i, LOCALLOCK::lockOwners, LOCALLOCKOWNER::nLocks, LOCALLOCK::numLockOwners, LOCALLOCKOWNER::owner, ResourceOwnerForgetLock(), and ResourceOwnerRememberLock().
Referenced by LockReassignCurrentOwner().
{
LOCALLOCKOWNER *lockOwners;
int i;
int ic = -1;
int ip = -1;
/*
* Scan to see if there are any locks belonging to current owner or
* its parent
*/
lockOwners = locallock->lockOwners;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == CurrentResourceOwner)
ic = i;
else if (lockOwners[i].owner == parent)
ip = i;
}
if (ic < 0)
return; /* no current locks */
if (ip < 0)
{
/* Parent has no slot, so just give it the child's slot */
lockOwners[ic].owner = parent;
ResourceOwnerRememberLock(parent, locallock);
}
else
{
/* Merge child's count with parent's */
lockOwners[ip].nLocks += lockOwners[ic].nLocks;
/* compact out unused slot */
locallock->numLockOwners--;
if (ic < locallock->numLockOwners)
lockOwners[ic] = lockOwners[locallock->numLockOwners];
}
ResourceOwnerForgetLock(CurrentResourceOwner, locallock);
}
| static void LockRefindAndRelease | ( | LockMethod | lockMethodTable, | |
| PGPROC * | proc, | |||
| LOCKTAG * | locktag, | |||
| LOCKMODE | lockmode, | |||
| bool | decrement_strong_lock_count | |||
| ) | [static] |
Definition at line 2830 of file lock.c.
References CleanUpLock(), ConflictsWithRelationFastPath, FastPathStrongRelationLockData::count, elog, FastPathStrongLockHashPartition, hash_search_with_hash_value(), PROCLOCK::holdMask, LOCKBIT_ON, LockHashPartitionLock, LockMethodData::lockModeNames, LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), FastPathStrongRelationLockData::mutex, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, PANIC, PROCLOCK_PRINT, ProcLockHashCode(), SpinLockAcquire, SpinLockRelease, LOCK::tag, UnGrantLock(), and WARNING.
Referenced by lock_twophase_postcommit(), LockReleaseAll(), and VirtualXactLockTableCleanup().
{
LOCK *lock;
PROCLOCK *proclock;
PROCLOCKTAG proclocktag;
uint32 hashcode;
uint32 proclock_hashcode;
LWLockId partitionLock;
bool wakeupNeeded;
hashcode = LockTagHashCode(locktag);
partitionLock = LockHashPartitionLock(hashcode);
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
* Re-find the lock object (it had better be there).
*/
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(void *) locktag,
hashcode,
HASH_FIND,
NULL);
if (!lock)
elog(PANIC, "failed to re-find shared lock object");
/*
* Re-find the proclock object (ditto).
*/
proclocktag.myLock = lock;
proclocktag.myProc = proc;
proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &proclocktag,
proclock_hashcode,
HASH_FIND,
NULL);
if (!proclock)
elog(PANIC, "failed to re-find shared proclock object");
/*
* Double-check that we are actually holding a lock of the type we want to
* release.
*/
if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
{
PROCLOCK_PRINT("lock_twophase_postcommit: WRONGTYPE", proclock);
LWLockRelease(partitionLock);
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
return;
}
/*
* Do the releasing. CleanUpLock will waken any now-wakable waiters.
*/
wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
CleanUpLock(lock, proclock,
lockMethodTable, hashcode,
wakeupNeeded);
LWLockRelease(partitionLock);
/*
* Decrement strong lock count. This logic is needed only for 2PC.
*/
if (decrement_strong_lock_count
&& ConflictsWithRelationFastPath(&lock->tag, lockmode))
{
uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
FastPathStrongRelationLocks->count[fasthashcode]--;
SpinLockRelease(&FastPathStrongRelationLocks->mutex);
}
}
Definition at line 1730 of file lock.c.
References Assert, PGPROC::backendLock, CleanUpLock(), CurrentResourceOwner, EligibleForRelationFastPath, elog, ERROR, FastPathLocalUseCount, FastPathUnGrantRelationLock(), hash_search(), hash_search_with_hash_value(), LOCALLOCK::hashcode, PROCLOCK::holdMask, i, lengthof, LOCALLOCK::lock, LOCALLOCKTAG::lock, LOCK_PRINT, LOCKBIT_ON, LockHashPartitionLock, LockMethodData::lockModeNames, LOCALLOCK::lockOwners, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_lockmethodid, LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MemSet, LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, MyProc, LOCALLOCK::nLocks, NULL, 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(), StandbyReleaseAllLocks(), StandbyReleaseLocks(), StandbyReleaseOldLocks(), UnlockDatabaseObject(), UnlockPage(), UnlockRelation(), UnlockRelationForExtension(), UnlockRelationId(), UnlockRelationIdForSession(), UnlockRelationOid(), UnlockSharedObject(), UnlockSharedObjectForSession(), UnlockTuple(), VirtualXactLock(), XactLockTableDelete(), and XactLockTableWait().
{
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
LOCALLOCKTAG localtag;
LOCALLOCK *locallock;
LOCK *lock;
PROCLOCK *proclock;
LWLockId partitionLock;
bool wakeupNeeded;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
elog(ERROR, "unrecognized lock mode: %d", lockmode);
#ifdef LOCK_DEBUG
if (LOCK_DEBUG_ENABLED(locktag))
elog(LOG, "LockRelease: lock [%u,%u] %s",
locktag->locktag_field1, locktag->locktag_field2,
lockMethodTable->lockModeNames[lockmode]);
#endif
/*
* Find the LOCALLOCK entry for this lock and lockmode
*/
MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
localtag.lock = *locktag;
localtag.mode = lockmode;
locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
(void *) &localtag,
HASH_FIND, NULL);
/*
* let the caller print its own error message, too. Do not ereport(ERROR).
*/
if (!locallock || locallock->nLocks <= 0)
{
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
return FALSE;
}
/*
* Decrease the count for the resource owner.
*/
{
LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
ResourceOwner owner;
int i;
/* Identify owner for lock */
if (sessionLock)
owner = NULL;
else
owner = CurrentResourceOwner;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == owner)
{
Assert(lockOwners[i].nLocks > 0);
if (--lockOwners[i].nLocks == 0)
{
if (owner != NULL)
ResourceOwnerForgetLock(owner, locallock);
/* compact out unused slot */
locallock->numLockOwners--;
if (i < locallock->numLockOwners)
lockOwners[i] = lockOwners[locallock->numLockOwners];
}
break;
}
}
if (i < 0)
{
/* don't release a lock belonging to another owner */
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
return FALSE;
}
}
/*
* Decrease the total local count. If we're still holding the lock, we're
* done.
*/
locallock->nLocks--;
if (locallock->nLocks > 0)
return TRUE;
/* Attempt fast release of any lock eligible for the fast path. */
if (EligibleForRelationFastPath(locktag, lockmode)
&& FastPathLocalUseCount > 0)
{
bool released;
/*
* We might not find the lock here, even if we originally entered it
* here. Another backend may have moved it to the main table.
*/
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
released = FastPathUnGrantRelationLock(locktag->locktag_field2,
lockmode);
LWLockRelease(MyProc->backendLock);
if (released)
{
RemoveLocalLock(locallock);
return TRUE;
}
}
/*
* Otherwise we've got to mess with the shared lock table.
*/
partitionLock = LockHashPartitionLock(locallock->hashcode);
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
* Normally, we don't need to re-find the lock or proclock, since we kept
* their addresses in the locallock table, and they couldn't have been
* removed while we were holding a lock on them. But it's possible that
* the locks have been moved to the main hash table by another backend, in
* which case we might need to go look them up after all.
*/
lock = locallock->lock;
if (!lock)
{
PROCLOCKTAG proclocktag;
bool found;
Assert(EligibleForRelationFastPath(locktag, lockmode));
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(const void *) locktag,
locallock->hashcode,
HASH_FIND,
&found);
Assert(found && lock != NULL);
locallock->lock = lock;
proclocktag.myLock = lock;
proclocktag.myProc = MyProc;
locallock->proclock = (PROCLOCK *) hash_search(LockMethodProcLockHash,
(void *) &proclocktag,
HASH_FIND, &found);
Assert(found);
}
LOCK_PRINT("LockRelease: found", lock, lockmode);
proclock = locallock->proclock;
PROCLOCK_PRINT("LockRelease: found", proclock);
/*
* Double-check that we are actually holding a lock of the type we want to
* release.
*/
if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
{
PROCLOCK_PRINT("LockRelease: WRONGTYPE", proclock);
LWLockRelease(partitionLock);
elog(WARNING, "you don't own a lock of type %s",
lockMethodTable->lockModeNames[lockmode]);
RemoveLocalLock(locallock);
return FALSE;
}
/*
* Do the releasing. CleanUpLock will waken any now-wakable waiters.
*/
wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
CleanUpLock(lock, proclock,
lockMethodTable, locallock->hashcode,
wakeupNeeded);
LWLockRelease(partitionLock);
RemoveLocalLock(locallock);
return TRUE;
}
| void LockReleaseAll | ( | LOCKMETHODID | lockmethodid, | |
| bool | allLocks | |||
| ) |
Definition at line 1923 of file lock.c.
References Assert, PGPROC::backendLock, CleanUpLock(), DEFAULT_LOCKMETHOD, EligibleForRelationFastPath, elog, ERROR, FastPathUnGrantRelationLock(), FirstLockMgrLock, LOCK::grantMask, hash_seq_init(), hash_seq_search(), PROCLOCK::holdMask, i, lengthof, LOCALLOCK_LOCKMETHOD, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_LOCKMETHOD, LOCK_PRINT, LOCKBIT_ON, LOCALLOCK::lockOwners, LockRefindAndRelease(), LOCKTAG::locktag_field2, LockTagHashCode(), LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, MyProc, PGPROC::myProcLocks, LOCK::nGranted, LOCALLOCKOWNER::nLocks, LOCALLOCK::nLocks, LOCK::nRequested, NULL, LockMethodData::numLockModes, LOCALLOCK::numLockOwners, offsetof, LOCALLOCKOWNER::owner, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), ResourceOwnerForgetLock(), SHMQueueNext(), LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, LockMethodData::trace_flag, UnGrantLock(), and VirtualXactLockTableCleanup().
Referenced by DiscardAll(), ProcReleaseLocks(), and ShutdownPostgres().
{
HASH_SEQ_STATUS status;
LockMethod lockMethodTable;
int i,
numLockModes;
LOCALLOCK *locallock;
LOCK *lock;
PROCLOCK *proclock;
int partition;
bool have_fast_path_lwlock = false;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
lockMethodTable = LockMethods[lockmethodid];
#ifdef LOCK_DEBUG
if (*(lockMethodTable->trace_flag))
elog(LOG, "LockReleaseAll: lockmethod=%d", lockmethodid);
#endif
/*
* Get rid of our fast-path VXID lock, if appropriate. Note that this is
* the only way that the lock we hold on our own VXID can ever get
* released: it is always and only released when a toplevel transaction
* ends.
*/
if (lockmethodid == DEFAULT_LOCKMETHOD)
VirtualXactLockTableCleanup();
numLockModes = lockMethodTable->numLockModes;
/*
* First we run through the locallock table and get rid of unwanted
* entries, then we scan the process's proclocks and get rid of those. We
* do this separately because we may have multiple locallock entries
* pointing to the same proclock, and we daren't end up with any dangling
* pointers.
*/
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
{
/*
* If the LOCALLOCK entry is unused, we must've run out of shared
* memory while trying to set up this lock. Just forget the local
* entry.
*/
if (locallock->nLocks == 0)
{
RemoveLocalLock(locallock);
continue;
}
/* Ignore items that are not of the lockmethod to be removed */
if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
continue;
/*
* If we are asked to release all locks, we can just zap the entry.
* Otherwise, must scan to see if there are session locks. We assume
* there is at most one lockOwners entry for session locks.
*/
if (!allLocks)
{
LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
/* If session lock is above array position 0, move it down to 0 */
for (i = 0; i < locallock->numLockOwners ; i++)
{
if (lockOwners[i].owner == NULL)
lockOwners[0] = lockOwners[i];
else
ResourceOwnerForgetLock(lockOwners[i].owner, locallock);
}
if (locallock->numLockOwners > 0 &&
lockOwners[0].owner == NULL &&
lockOwners[0].nLocks > 0)
{
/* Fix the locallock to show just the session locks */
locallock->nLocks = lockOwners[0].nLocks;
locallock->numLockOwners = 1;
/* We aren't deleting this locallock, so done */
continue;
}
else
locallock->numLockOwners = 0;
}
/*
* If the lock or proclock pointers are NULL, this lock was taken via
* the relation fast-path.
*/
if (locallock->proclock == NULL || locallock->lock == NULL)
{
LOCKMODE lockmode = locallock->tag.mode;
Oid relid;
/* Verify that a fast-path lock is what we've got. */
if (!EligibleForRelationFastPath(&locallock->tag.lock, lockmode))
elog(PANIC, "locallock table corrupted");
/*
* If we don't currently hold the LWLock that protects our
* fast-path data structures, we must acquire it before attempting
* to release the lock via the fast-path.
*/
if (!have_fast_path_lwlock)
{
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
have_fast_path_lwlock = true;
}
/* Attempt fast-path release. */
relid = locallock->tag.lock.locktag_field2;
if (FastPathUnGrantRelationLock(relid, lockmode))
{
RemoveLocalLock(locallock);
continue;
}
/*
* Our lock, originally taken via the fast path, has been
* transferred to the main lock table. That's going to require
* some extra work, so release our fast-path lock before starting.
*/
LWLockRelease(MyProc->backendLock);
have_fast_path_lwlock = false;
/*
* Now dump the lock. We haven't got a pointer to the LOCK or
* PROCLOCK in this case, so we have to handle this a bit
* differently than a normal lock release. Unfortunately, this
* requires an extra LWLock acquire-and-release cycle on the
* partitionLock, but hopefully it shouldn't happen often.
*/
LockRefindAndRelease(lockMethodTable, MyProc,
&locallock->tag.lock, lockmode, false);
RemoveLocalLock(locallock);
continue;
}
/* Mark the proclock to show we need to release this lockmode */
if (locallock->nLocks > 0)
locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
/* And remove the locallock hashtable entry */
RemoveLocalLock(locallock);
}
if (have_fast_path_lwlock)
LWLockRelease(MyProc->backendLock);
/*
* Now, scan each lock partition separately.
*/
for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
{
LWLockId partitionLock = FirstLockMgrLock + partition;
SHM_QUEUE *procLocks = &(MyProc->myProcLocks[partition]);
proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
offsetof(PROCLOCK, procLink));
if (!proclock)
continue; /* needn't examine this partition */
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
while (proclock)
{
bool wakeupNeeded = false;
PROCLOCK *nextplock;
/* Get link first, since we may unlink/delete this proclock */
nextplock = (PROCLOCK *)
SHMQueueNext(procLocks, &proclock->procLink,
offsetof(PROCLOCK, procLink));
Assert(proclock->tag.myProc == MyProc);
lock = proclock->tag.myLock;
/* Ignore items that are not of the lockmethod to be removed */
if (LOCK_LOCKMETHOD(*lock) != lockmethodid)
goto next_item;
/*
* In allLocks mode, force release of all locks even if locallock
* table had problems
*/
if (allLocks)
proclock->releaseMask = proclock->holdMask;
else
Assert((proclock->releaseMask & ~proclock->holdMask) == 0);
/*
* Ignore items that have nothing to be released, unless they have
* holdMask == 0 and are therefore recyclable
*/
if (proclock->releaseMask == 0 && proclock->holdMask != 0)
goto next_item;
PROCLOCK_PRINT("LockReleaseAll", proclock);
LOCK_PRINT("LockReleaseAll", lock, 0);
Assert(lock->nRequested >= 0);
Assert(lock->nGranted >= 0);
Assert(lock->nGranted <= lock->nRequested);
Assert((proclock->holdMask & ~lock->grantMask) == 0);
/*
* Release the previously-marked lock modes
*/
for (i = 1; i <= numLockModes; i++)
{
if (proclock->releaseMask & LOCKBIT_ON(i))
wakeupNeeded |= UnGrantLock(lock, i, proclock,
lockMethodTable);
}
Assert((lock->nRequested >= 0) && (lock->nGranted >= 0));
Assert(lock->nGranted <= lock->nRequested);
LOCK_PRINT("LockReleaseAll: updated", lock, 0);
proclock->releaseMask = 0;
/* CleanUpLock will wake up waiters if needed. */
CleanUpLock(lock, proclock,
lockMethodTable,
LockTagHashCode(&lock->tag),
wakeupNeeded);
next_item:
proclock = nextplock;
} /* loop over PROCLOCKs within this partition */
LWLockRelease(partitionLock);
} /* loop over partitions */
#ifdef LOCK_DEBUG
if (*(lockMethodTable->trace_flag))
elog(LOG, "LockReleaseAll done");
#endif
}
| void LockReleaseCurrentOwner | ( | LOCALLOCK ** | locallocks, | |
| int | nlocks | |||
| ) |
Definition at line 2203 of file lock.c.
References hash_seq_init(), hash_seq_search(), i, NULL, and ReleaseLockIfHeld().
Referenced by ResourceOwnerReleaseInternal().
{
if (locallocks == NULL)
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
ReleaseLockIfHeld(locallock, false);
}
else
{
int i;
for (i = nlocks - 1; i >= 0; i--)
ReleaseLockIfHeld(locallocks[i], false);
}
}
| void LockReleaseSession | ( | LOCKMETHODID | lockmethodid | ) |
Definition at line 2173 of file lock.c.
References elog, ERROR, hash_seq_init(), hash_seq_search(), lengthof, LOCALLOCK_LOCKMETHOD, NULL, and ReleaseLockIfHeld().
Referenced by pg_advisory_unlock_all().
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
{
/* Ignore items that are not of the specified lock method */
if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
continue;
ReleaseLockIfHeld(locallock, true);
}
}
| Size LockShmemSize | ( | void | ) |
Definition at line 3210 of file lock.c.
References add_size(), hash_estimate_size(), and NLOCKENTS.
Referenced by CreateSharedMemoryAndSemaphores().
{
Size size = 0;
long max_table_size;
/* lock hash table */
max_table_size = NLOCKENTS();
size = add_size(size, hash_estimate_size(max_table_size, sizeof(LOCK)));
/* proclock hash table */
max_table_size *= 2;
size = add_size(size, hash_estimate_size(max_table_size, sizeof(PROCLOCK)));
/*
* Since NLOCKENTS is only an estimate, add 10% safety margin.
*/
size = add_size(size, size / 10);
return size;
}
Definition at line 479 of file lock.c.
References get_hash_value().
Referenced by CheckDeadLock(), GetLockConflicts(), lock_twophase_recover(), LockAcquireExtended(), LockRefindAndRelease(), LockReleaseAll(), proclock_hash(), and VirtualXactLock().
{
return get_hash_value(LockMethodLockHash, (const void *) locktag);
}
| void PostPrepare_Locks | ( | TransactionId | xid | ) |
Definition at line 3036 of file lock.c.
References Assert, elog, END_CRIT_SECTION, ereport, errcode(), errmsg(), FirstLockMgrLock, LOCK::grantMask, hash_seq_init(), hash_seq_search(), hash_update_hash_key(), PROCLOCK::holdMask, i, LOCALLOCKTAG::lock, LOCALLOCK::lock, LOCK_PRINT, LOCKBIT_ON, LOCALLOCK::lockOwners, LOCKTAG::locktag_type, LOCKTAG_VIRTUALTRANSACTION, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), LOCALLOCKTAG::mode, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, MyProc, PGPROC::myProcLocks, LOCK::nGranted, LOCALLOCK::nLocks, LOCK::nRequested, NULL, LOCALLOCK::numLockOwners, offsetof, PANIC, PROCLOCK::procLink, LOCALLOCK::proclock, PROCLOCK_PRINT, PROCLOCK::releaseMask, RemoveLocalLock(), SHMQueueDelete(), SHMQueueInsertBefore(), SHMQueueNext(), START_CRIT_SECTION, LOCK::tag, PROCLOCK::tag, LOCALLOCK::tag, and TwoPhaseGetDummyProc().
Referenced by PrepareTransaction().
{
PGPROC *newproc = TwoPhaseGetDummyProc(xid);
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
LOCK *lock;
PROCLOCK *proclock;
PROCLOCKTAG proclocktag;
int partition;
/* This is a critical section: any error means big trouble */
START_CRIT_SECTION();
/*
* First we run through the locallock table and get rid of unwanted
* entries, then we scan the process's proclocks and transfer them to the
* target proc.
*
* We do this separately because we may have multiple locallock entries
* pointing to the same proclock, and we daren't end up with any dangling
* pointers.
*/
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
{
LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
bool haveSessionLock;
bool haveXactLock;
int i;
if (locallock->proclock == NULL || locallock->lock == NULL)
{
/*
* We must've run out of shared memory while trying to set up this
* lock. Just forget the local entry.
*/
Assert(locallock->nLocks == 0);
RemoveLocalLock(locallock);
continue;
}
/* Ignore VXID locks */
if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
continue;
/* Scan to see whether we hold it at session or transaction level */
haveSessionLock = haveXactLock = false;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == NULL)
haveSessionLock = true;
else
haveXactLock = true;
}
/* Ignore it if we have only session lock */
if (!haveXactLock)
continue;
/* This can't happen, because we already checked it */
if (haveSessionLock)
ereport(PANIC,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
/* Mark the proclock to show we need to release this lockmode */
if (locallock->nLocks > 0)
locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
/* And remove the locallock hashtable entry */
RemoveLocalLock(locallock);
}
/*
* Now, scan each lock partition separately.
*/
for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
{
LWLockId partitionLock = FirstLockMgrLock + partition;
SHM_QUEUE *procLocks = &(MyProc->myProcLocks[partition]);
proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
offsetof(PROCLOCK, procLink));
if (!proclock)
continue; /* needn't examine this partition */
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
while (proclock)
{
PROCLOCK *nextplock;
/* Get link first, since we may unlink/relink this proclock */
nextplock = (PROCLOCK *)
SHMQueueNext(procLocks, &proclock->procLink,
offsetof(PROCLOCK, procLink));
Assert(proclock->tag.myProc == MyProc);
lock = proclock->tag.myLock;
/* Ignore VXID locks */
if (lock->tag.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
goto next_item;
PROCLOCK_PRINT("PostPrepare_Locks", proclock);
LOCK_PRINT("PostPrepare_Locks", lock, 0);
Assert(lock->nRequested >= 0);
Assert(lock->nGranted >= 0);
Assert(lock->nGranted <= lock->nRequested);
Assert((proclock->holdMask & ~lock->grantMask) == 0);
/* Ignore it if nothing to release (must be a session lock) */
if (proclock->releaseMask == 0)
goto next_item;
/* Else we should be releasing all locks */
if (proclock->releaseMask != proclock->holdMask)
elog(PANIC, "we seem to have dropped a bit somewhere");
/*
* We cannot simply modify proclock->tag.myProc to reassign
* ownership of the lock, because that's part of the hash key and
* the proclock would then be in the wrong hash chain. Instead
* use hash_update_hash_key. (We used to create a new hash entry,
* but that risks out-of-memory failure if other processes are
* busy making proclocks too.) We must unlink the proclock from
* our procLink chain and put it into the new proc's chain, too.
*
* Note: the updated proclock hash key will still belong to the
* same hash partition, cf proclock_hash(). So the partition
* lock we already hold is sufficient for this.
*/
SHMQueueDelete(&proclock->procLink);
/*
* Create the new hash key for the proclock.
*/
proclocktag.myLock = lock;
proclocktag.myProc = newproc;
/*
* Update the proclock. We should not find any existing entry
* for the same hash key, since there can be only one entry for
* any given lock with my own proc.
*/
if (!hash_update_hash_key(LockMethodProcLockHash,
(void *) proclock,
(void *) &proclocktag))
elog(PANIC, "duplicate entry found while reassigning a prepared transaction's locks");
/* Re-link into the new proc's proclock list */
SHMQueueInsertBefore(&(newproc->myProcLocks[partition]),
&proclock->procLink);
PROCLOCK_PRINT("PostPrepare_Locks: updated", proclock);
next_item:
proclock = nextplock;
} /* loop over PROCLOCKs within this partition */
LWLockRelease(partitionLock);
} /* loop over partitions */
END_CRIT_SECTION();
}
Definition at line 496 of file lock.c.
References Assert, LockTagHashCode(), PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, PointerGetDatum, and LOCK::tag.
{
const PROCLOCKTAG *proclocktag = (const PROCLOCKTAG *) key;
uint32 lockhash;
Datum procptr;
Assert(keysize == sizeof(PROCLOCKTAG));
/* Look into the associated LOCK object, and compute its hash code */
lockhash = LockTagHashCode(&proclocktag->myLock->tag);
/*
* To make the hash code also depend on the PGPROC, we xor the proc
* struct's address into the hash code, left-shifted so that the
* partition-number bits don't change. Since this is only a hash, we
* don't care if we lose high-order bits of the address; use an
* intermediate variable to suppress cast-pointer-to-int warnings.
*/
procptr = PointerGetDatum(proclocktag->myProc);
lockhash ^= ((uint32) procptr) << LOG2_NUM_LOCK_PARTITIONS;
return lockhash;
}
| static uint32 ProcLockHashCode | ( | const PROCLOCKTAG * | proclocktag, | |
| uint32 | hashcode | |||
| ) | [inline, static] |
Definition at line 527 of file lock.c.
References PROCLOCKTAG::myProc, and PointerGetDatum.
Referenced by CleanUpLock(), FastPathGetRelationLockEntry(), lock_twophase_recover(), LockAcquireExtended(), LockRefindAndRelease(), and SetupLockInTable().
{
uint32 lockhash = hashcode;
Datum procptr;
/*
* This must match proclock_hash()!
*/
procptr = PointerGetDatum(proclocktag->myProc);
lockhash ^= ((uint32) procptr) << LOG2_NUM_LOCK_PARTITIONS;
return lockhash;
}
Definition at line 2238 of file lock.c.
References Assert, CurrentResourceOwner, elog, i, LOCALLOCKTAG::lock, LOCALLOCK::lockOwners, LockRelease(), LOCALLOCKTAG::mode, LOCALLOCKOWNER::nLocks, LOCALLOCK::nLocks, NULL, LOCALLOCK::numLockOwners, ResourceOwnerForgetLock(), LOCALLOCK::tag, and WARNING.
Referenced by LockReleaseCurrentOwner(), and LockReleaseSession().
{
ResourceOwner owner;
LOCALLOCKOWNER *lockOwners;
int i;
/* Identify owner for lock (must match LockRelease!) */
if (sessionLock)
owner = NULL;
else
owner = CurrentResourceOwner;
/* Scan to see if there are any locks belonging to the target owner */
lockOwners = locallock->lockOwners;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == owner)
{
Assert(lockOwners[i].nLocks > 0);
if (lockOwners[i].nLocks < locallock->nLocks)
{
/*
* We will still hold this lock after forgetting this
* ResourceOwner.
*/
locallock->nLocks -= lockOwners[i].nLocks;
/* compact out unused slot */
locallock->numLockOwners--;
if (owner != NULL)
ResourceOwnerForgetLock(owner, locallock);
if (i < locallock->numLockOwners)
lockOwners[i] = lockOwners[locallock->numLockOwners];
}
else
{
Assert(lockOwners[i].nLocks == locallock->nLocks);
/* We want to call LockRelease just once */
lockOwners[i].nLocks = 1;
locallock->nLocks = 1;
if (!LockRelease(&locallock->tag.lock,
locallock->tag.mode,
sessionLock))
elog(WARNING, "ReleaseLockIfHeld: failed??");
}
break;
}
}
}
Definition at line 1673 of file lock.c.
References Assert, CleanUpLock(), LOCK::granted, lengthof, PGPROC::links, LOCK_LOCKMETHOD, LOCKBIT_OFF, SHM_QUEUE::next, LOCK::nGranted, LOCK::nRequested, NULL, LOCK::requested, SHMQueueDelete(), PROC_QUEUE::size, STATUS_WAITING, PGPROC::waitLock, PGPROC::waitLockMode, LOCK::waitMask, PGPROC::waitProcLock, LOCK::waitProcs, and PGPROC::waitStatus.
Referenced by CheckDeadLock(), LockErrorCleanup(), and ProcSleep().
{
LOCK *waitLock = proc->waitLock;
PROCLOCK *proclock = proc->waitProcLock;
LOCKMODE lockmode = proc->waitLockMode;
LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*waitLock);
/* Make sure proc is waiting */
Assert(proc->waitStatus == STATUS_WAITING);
Assert(proc->links.next != NULL);
Assert(waitLock);
Assert(waitLock->waitProcs.size > 0);
Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
/* Remove proc from lock's wait queue */
SHMQueueDelete(&(proc->links));
waitLock->waitProcs.size--;
/* Undo increments of request counts by waiting process */
Assert(waitLock->nRequested > 0);
Assert(waitLock->nRequested > proc->waitLock->nGranted);
waitLock->nRequested--;
Assert(waitLock->requested[lockmode] > 0);
waitLock->requested[lockmode]--;
/* don't forget to clear waitMask bit if appropriate */
if (waitLock->granted[lockmode] == waitLock->requested[lockmode])
waitLock->waitMask &= LOCKBIT_OFF(lockmode);
/* Clean up the proc's own state, and pass it the ok/fail signal */
proc->waitLock = NULL;
proc->waitProcLock = NULL;
proc->waitStatus = STATUS_ERROR;
/*
* Delete the proclock immediately if it represents no already-held locks.
* (This must happen now because if the owner of the lock decides to
* release it, and the requested/granted counts then go to zero,
* LockRelease expects there to be no remaining proclocks.) Then see if
* any other waiters for the lock can be woken up now.
*/
CleanUpLock(waitLock, proclock,
LockMethods[lockmethodid], hashcode,
true);
}
| static void RemoveLocalLock | ( | LOCALLOCK * | locallock | ) | [static] |
Definition at line 1211 of file lock.c.
References Assert, FastPathStrongRelationLockData::count, elog, FastPathStrongLockHashPartition, HASH_REMOVE, hash_search(), LOCALLOCK::hashcode, LOCALLOCK::holdsStrongLockCount, i, LOCALLOCK::lockOwners, FastPathStrongRelationLockData::mutex, NULL, LOCALLOCK::numLockOwners, LOCALLOCKOWNER::owner, pfree(), ResourceOwnerForgetLock(), SpinLockAcquire, SpinLockRelease, LOCALLOCK::tag, and WARNING.
Referenced by LockAcquireExtended(), LockHasWaiters(), LockRelease(), LockReleaseAll(), and PostPrepare_Locks().
{
int i;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (locallock->lockOwners[i].owner != NULL)
ResourceOwnerForgetLock(locallock->lockOwners[i].owner, locallock);
}
pfree(locallock->lockOwners);
locallock->lockOwners = NULL;
if (locallock->holdsStrongLockCount)
{
uint32 fasthashcode;
fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
FastPathStrongRelationLocks->count[fasthashcode]--;
locallock->holdsStrongLockCount = FALSE;
SpinLockRelease(&FastPathStrongRelationLocks->mutex);
}
if (!hash_search(LockMethodLocalHash,
(void *) &(locallock->tag),
HASH_REMOVE, NULL))
elog(WARNING, "locallock table corrupted");
}
| static PROCLOCK * SetupLockInTable | ( | LockMethod | lockMethodTable, | |
| PGPROC * | proc, | |||
| const LOCKTAG * | locktag, | |||
| uint32 | hashcode, | |||
| LOCKMODE | lockmode | |||
| ) | [static] |
Definition at line 1041 of file lock.c.
References Assert, elog, ERROR, LOCK::granted, LOCK::grantMask, HASH_REMOVE, hash_search_with_hash_value(), PROCLOCK::holdMask, i, LOCK_PRINT, LOCKBIT_ON, LockHashPartition, PROCLOCK::lockLink, LockMethodData::lockModeNames, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOG, MAX_LOCKMODES, MemSet, PROCLOCKTAG::myLock, PROCLOCKTAG::myProc, PGPROC::myProcLocks, LOCK::nGranted, LOCK::nRequested, NULL, LockMethodData::numLockModes, PANIC, PROCLOCK::procLink, PROCLOCK_PRINT, ProcLockHashCode(), LOCK::procLocks, ProcQueueInit(), PROCLOCK::releaseMask, LOCK::requested, SHMQueueEmpty(), SHMQueueInit(), SHMQueueInsertBefore(), LOCK::tag, LOCK::waitMask, and LOCK::waitProcs.
Referenced by FastPathGetRelationLockEntry(), FastPathTransferRelationLocks(), LockAcquireExtended(), and VirtualXactLock().
{
LOCK *lock;
PROCLOCK *proclock;
PROCLOCKTAG proclocktag;
uint32 proclock_hashcode;
bool found;
/*
* Find or create a lock with this tag.
*
* Note: if the locallock object already existed, it might have a pointer
* to the lock already ... but we probably should not assume that that
* pointer is valid, since a lock object with no locks can go away
* anytime.
*/
lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
(const void *) locktag,
hashcode,
HASH_ENTER_NULL,
&found);
if (!lock)
return NULL;
/*
* if it's a new lock object, initialize it
*/
if (!found)
{
lock->grantMask = 0;
lock->waitMask = 0;
SHMQueueInit(&(lock->procLocks));
ProcQueueInit(&(lock->waitProcs));
lock->nRequested = 0;
lock->nGranted = 0;
MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
LOCK_PRINT("LockAcquire: new", lock, lockmode);
}
else
{
LOCK_PRINT("LockAcquire: found", lock, lockmode);
Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
Assert(lock->nGranted <= lock->nRequested);
}
/*
* Create the hash key for the proclock table.
*/
proclocktag.myLock = lock;
proclocktag.myProc = proc;
proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
/*
* Find or create a proclock entry with this tag
*/
proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
(void *) &proclocktag,
proclock_hashcode,
HASH_ENTER_NULL,
&found);
if (!proclock)
{
/* Ooops, not enough shmem for the proclock */
if (lock->nRequested == 0)
{
/*
* There are no other requestors of this lock, so garbage-collect
* the lock object. We *must* do this to avoid a permanent leak
* of shared memory, because there won't be anything to cause
* anyone to release the lock object later.
*/
Assert(SHMQueueEmpty(&(lock->procLocks)));
if (!hash_search_with_hash_value(LockMethodLockHash,
(void *) &(lock->tag),
hashcode,
HASH_REMOVE,
NULL))
elog(PANIC, "lock table corrupted");
}
return NULL;
}
/*
* If new, initialize the new entry
*/
if (!found)
{
uint32 partition = LockHashPartition(hashcode);
proclock->holdMask = 0;
proclock->releaseMask = 0;
/* Add proclock to appropriate lists */
SHMQueueInsertBefore(&lock->procLocks, &proclock->lockLink);
SHMQueueInsertBefore(&(proc->myProcLocks[partition]),
&proclock->procLink);
PROCLOCK_PRINT("LockAcquire: new", proclock);
}
else
{
PROCLOCK_PRINT("LockAcquire: found", proclock);
Assert((proclock->holdMask & ~lock->grantMask) == 0);
#ifdef CHECK_DEADLOCK_RISK
/*
* Issue warning if we already hold a lower-level lock on this object
* and do not hold a lock of the requested level or higher. This
* indicates a deadlock-prone coding practice (eg, we'd have a
* deadlock if another backend were following the same code path at
* about the same time).
*
* This is not enabled by default, because it may generate log entries
* about user-level coding practices that are in fact safe in context.
* It can be enabled to help find system-level problems.
*
* XXX Doing numeric comparison on the lockmodes is a hack; it'd be
* better to use a table. For now, though, this works.
*/
{
int i;
for (i = lockMethodTable->numLockModes; i > 0; i--)
{
if (proclock->holdMask & LOCKBIT_ON(i))
{
if (i >= (int) lockmode)
break; /* safe: we have a lock >= req level */
elog(LOG, "deadlock risk: raising lock level"
" from %s to %s on object %u/%u/%u",
lockMethodTable->lockModeNames[i],
lockMethodTable->lockModeNames[lockmode],
lock->tag.locktag_field1, lock->tag.locktag_field2,
lock->tag.locktag_field3);
break;
}
}
}
#endif /* CHECK_DEADLOCK_RISK */
}
/*
* lock->nRequested and lock->requested[] count the total number of
* requests, whether granted or waiting, so increment those immediately.
* The other counts don't increment till we get the lock.
*/
lock->nRequested++;
lock->requested[lockmode]++;
Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
/*
* We shouldn't already hold the desired lock; else locallock table is
* broken.
*/
if (proclock->holdMask & LOCKBIT_ON(lockmode))
elog(ERROR, "lock %s on object %u/%u/%u is already held",
lockMethodTable->lockModeNames[lockmode],
lock->tag.locktag_field1, lock->tag.locktag_field2,
lock->tag.locktag_field3);
return proclock;
}
| static bool UnGrantLock | ( | LOCK * | lock, | |
| LOCKMODE | lockmode, | |||
| PROCLOCK * | proclock, | |||
| LockMethod | lockMethodTable | |||
| ) | [static] |
Definition at line 1348 of file lock.c.
References Assert, LockMethodData::conflictTab, LOCK::granted, LOCK::grantMask, PROCLOCK::holdMask, LOCK_PRINT, LOCKBIT_OFF, LOCK::nGranted, LOCK::nRequested, PROCLOCK_PRINT, LOCK::requested, and LOCK::waitMask.
Referenced by LockRefindAndRelease(), LockRelease(), and LockReleaseAll().
{
bool wakeupNeeded = false;
Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
Assert(lock->nGranted <= lock->nRequested);
/*
* fix the general lock stats
*/
lock->nRequested--;
lock->requested[lockmode]--;
lock->nGranted--;
lock->granted[lockmode]--;
if (lock->granted[lockmode] == 0)
{
/* change the conflict mask. No more of this lock type. */
lock->grantMask &= LOCKBIT_OFF(lockmode);
}
LOCK_PRINT("UnGrantLock: updated", lock, lockmode);
/*
* We need only run ProcLockWakeup if the released lock conflicts with at
* least one of the lock types requested by waiter(s). Otherwise whatever
* conflict made them wait must still exist. NOTE: before MVCC, we could
* skip wakeup if lock->granted[lockmode] was still positive. But that's
* not true anymore, because the remaining granted locks might belong to
* some waiter, who could now be awakened because he doesn't conflict with
* his own locks.
*/
if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
wakeupNeeded = true;
/*
* Now fix the per-proclock state.
*/
proclock->holdMask &= LOCKBIT_OFF(lockmode);
PROCLOCK_PRINT("UnGrantLock: updated", proclock);
return wakeupNeeded;
}
| bool VirtualXactLock | ( | VirtualTransactionId | vxid, | |
| bool | wait | |||
| ) |
Definition at line 3930 of file lock.c.
References Assert, PGPROC::backendId, VirtualTransactionId::backendId, BackendIdGetProc(), PGPROC::backendLock, DEFAULT_LOCKMETHOD, ereport, errcode(), errhint(), errmsg(), ERROR, ExclusiveLock, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, GrantLock(), VirtualTransactionId::localTransactionId, LockAcquire(), LockHashPartitionLock, LockRelease(), LockTagHashCode(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PROCLOCKTAG::myLock, NULL, SET_LOCKTAG_VIRTUALTRANSACTION, SetupLockInTable(), ShareLock, PROCLOCK::tag, and VirtualTransactionIdIsValid.
Referenced by DefineIndex(), index_drop(), and ResolveRecoveryConflictWithVirtualXIDs().
{
LOCKTAG tag;
PGPROC *proc;
Assert(VirtualTransactionIdIsValid(vxid));
SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
/*
* If a lock table entry must be made, this is the PGPROC on whose behalf
* it must be done. Note that the transaction might end or the PGPROC
* might be reassigned to a new backend before we get around to examining
* it, but it doesn't matter. If we find upon examination that the
* relevant lxid is no longer running here, that's enough to prove that
* it's no longer running anywhere.
*/
proc = BackendIdGetProc(vxid.backendId);
if (proc == NULL)
return true;
/*
* We must acquire this lock before checking the backendId and lxid
* against the ones we're waiting for. The target backend will only set
* or clear lxid while holding this lock.
*/
LWLockAcquire(proc->backendLock, LW_EXCLUSIVE);
/* If the transaction has ended, our work here is done. */
if (proc->backendId != vxid.backendId
|| proc->fpLocalTransactionId != vxid.localTransactionId)
{
LWLockRelease(proc->backendLock);
return true;
}
/*
* If we aren't asked to wait, there's no need to set up a lock table
* entry. The transaction is still in progress, so just return false.
*/
if (!wait)
{
LWLockRelease(proc->backendLock);
return false;
}
/*
* OK, we're going to need to sleep on the VXID. But first, we must set
* up the primary lock table entry, if needed (ie, convert the proc's
* fast-path lock on its VXID to a regular lock).
*/
if (proc->fpVXIDLock)
{
PROCLOCK *proclock;
uint32 hashcode;
LWLockId partitionLock;
hashcode = LockTagHashCode(&tag);
partitionLock = LockHashPartitionLock(hashcode);
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
proclock = SetupLockInTable(LockMethods[DEFAULT_LOCKMETHOD], proc,
&tag, hashcode, ExclusiveLock);
if (!proclock)
{
LWLockRelease(partitionLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory"),
errhint("You might need to increase max_locks_per_transaction.")));
}
GrantLock(proclock->tag.myLock, proclock, ExclusiveLock);
LWLockRelease(partitionLock);
proc->fpVXIDLock = false;
}
/* Done with proc->fpLockBits */
LWLockRelease(proc->backendLock);
/* Time to wait. */
(void) LockAcquire(&tag, ShareLock, false, false);
LockRelease(&tag, ShareLock, false);
return true;
}
| void VirtualXactLockTableCleanup | ( | void | ) |
Definition at line 3883 of file lock.c.
References Assert, VirtualTransactionId::backendId, PGPROC::backendId, PGPROC::backendLock, DEFAULT_LOCKMETHOD, ExclusiveLock, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, InvalidBackendId, VirtualTransactionId::localTransactionId, LocalTransactionIdIsValid, LockRefindAndRelease(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyBackendId, MyProc, and SET_LOCKTAG_VIRTUALTRANSACTION.
Referenced by LockReleaseAll(), and ShutdownRecoveryTransactionEnvironment().
{
bool fastpath;
LocalTransactionId lxid;
Assert(MyProc->backendId != InvalidBackendId);
/*
* Clean up shared memory state.
*/
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
fastpath = MyProc->fpVXIDLock;
lxid = MyProc->fpLocalTransactionId;
MyProc->fpVXIDLock = false;
MyProc->fpLocalTransactionId = InvalidLocalTransactionId;
LWLockRelease(MyProc->backendLock);
/*
* If fpVXIDLock has been cleared without touching fpLocalTransactionId,
* that means someone transferred the lock to the main lock table.
*/
if (!fastpath && LocalTransactionIdIsValid(lxid))
{
VirtualTransactionId vxid;
LOCKTAG locktag;
vxid.backendId = MyBackendId;
vxid.localTransactionId = lxid;
SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid);
LockRefindAndRelease(LockMethods[DEFAULT_LOCKMETHOD], MyProc,
&locktag, ExclusiveLock, false);
}
}
| void VirtualXactLockTableInsert | ( | VirtualTransactionId | vxid | ) |
Definition at line 3860 of file lock.c.
References Assert, VirtualTransactionId::backendId, PGPROC::backendId, PGPROC::backendLock, PGPROC::fpLocalTransactionId, PGPROC::fpVXIDLock, InvalidLocalTransactionId, VirtualTransactionId::localTransactionId, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MyProc, and VirtualTransactionIdIsValid.
Referenced by InitRecoveryTransactionEnvironment(), and StartTransaction().
{
Assert(VirtualTransactionIdIsValid(vxid));
LWLockAcquire(MyProc->backendLock, LW_EXCLUSIVE);
Assert(MyProc->backendId == vxid.backendId);
Assert(MyProc->fpLocalTransactionId == InvalidLocalTransactionId);
Assert(MyProc->fpVXIDLock == false);
MyProc->fpVXIDLock = true;
MyProc->fpLocalTransactionId = vxid.localTransactionId;
LWLockRelease(MyProc->backendLock);
}
| static void WaitOnLock | ( | LOCALLOCK * | locallock, | |
| ResourceOwner | owner | |||
| ) | [static] |
Definition at line 1566 of file lock.c.
References DeadLockReport(), get_ps_display(), LOCALLOCK::hashcode, LOCALLOCK_LOCKMETHOD, LOCALLOCK::lock, LOCK_PRINT, LockHashPartitionLock, LWLockRelease(), LOCALLOCKTAG::mode, palloc(), pfree(), PG_CATCH, PG_END_TRY, PG_RE_THROW, PG_TRY, pgstat_report_waiting(), ProcSleep(), set_ps_display(), STATUS_OK, LOCALLOCK::tag, and update_process_title.
Referenced by LockAcquireExtended().
{
LOCKMETHODID lockmethodid = LOCALLOCK_LOCKMETHOD(*locallock);
LockMethod lockMethodTable = LockMethods[lockmethodid];
char *volatile new_status = NULL;
LOCK_PRINT("WaitOnLock: sleeping on lock",
locallock->lock, locallock->tag.mode);
/* Report change to waiting status */
if (update_process_title)
{
const char *old_status;
int len;
old_status = get_ps_display(&len);
new_status = (char *) palloc(len + 8 + 1);
memcpy(new_status, old_status, len);
strcpy(new_status + len, " waiting");
set_ps_display(new_status, false);
new_status[len] = '\0'; /* truncate off " waiting" */
}
pgstat_report_waiting(true);
awaitedLock = locallock;
awaitedOwner = owner;
/*
* NOTE: Think not to put any shared-state cleanup after the call to
* ProcSleep, in either the normal or failure path. The lock state must
* be fully set by the lock grantor, or by CheckDeadLock if we give up
* waiting for the lock. This is necessary because of the possibility
* that a cancel/die interrupt will interrupt ProcSleep after someone else
* grants us the lock, but before we've noticed it. Hence, after granting,
* the locktable state must fully reflect the fact that we own the lock;
* we can't do additional work on return.
*
* We can and do use a PG_TRY block to try to clean up after failure, but
* this still has a major limitation: elog(FATAL) can occur while waiting
* (eg, a "die" interrupt), and then control won't come back here. So all
* cleanup of essential state should happen in LockErrorCleanup, not here.
* We can use PG_TRY to clear the "waiting" status flags, since doing that
* is unimportant if the process exits.
*/
PG_TRY();
{
if (ProcSleep(locallock, lockMethodTable) != STATUS_OK)
{
/*
* We failed as a result of a deadlock, see CheckDeadLock(). Quit
* now.
*/
awaitedLock = NULL;
LOCK_PRINT("WaitOnLock: aborting on lock",
locallock->lock, locallock->tag.mode);
LWLockRelease(LockHashPartitionLock(locallock->hashcode));
/*
* Now that we aren't holding the partition lock, we can give an
* error report including details about the detected deadlock.
*/
DeadLockReport();
/* not reached */
}
}
PG_CATCH();
{
/* In this path, awaitedLock remains set until LockErrorCleanup */
/* Report change to non-waiting status */
pgstat_report_waiting(false);
if (update_process_title)
{
set_ps_display(new_status, false);
pfree(new_status);
}
/* and propagate the error */
PG_RE_THROW();
}
PG_END_TRY();
awaitedLock = NULL;
/* Report change to non-waiting status */
pgstat_report_waiting(false);
if (update_process_title)
{
set_ps_display(new_status, false);
pfree(new_status);
}
LOCK_PRINT("WaitOnLock: wakeup on lock",
locallock->lock, locallock->tag.mode);
}
LOCALLOCK* awaitedLock [static] |
ResourceOwner awaitedOwner [static] |
const LockMethodData default_lockmethod [static] |
{
AccessExclusiveLock,
LockConflicts,
lock_mode_names,
&Dummy_trace
}
bool Dummy_trace = false [static] |
int FastPathLocalUseCount = 0 [static] |
Definition at line 168 of file lock.c.
Referenced by FastPathGrantRelationLock(), FastPathUnGrantRelationLock(), LockAcquireExtended(), and LockRelease().
const char* const lock_mode_names[] [static] |
const LOCKMASK LockConflicts[] [static] |
HTAB* LockMethodLocalHash [static] |
HTAB* LockMethodLockHash [static] |
HTAB* LockMethodProcLockHash [static] |
const LockMethod LockMethods[] [static] |
{
NULL,
&default_lockmethod,
&user_lockmethod
}
Definition at line 51 of file lock.c.
Referenced by BootStrapXLOG(), CheckRequiredParameterValues(), and XLogReportParameters().
LOCALLOCK* StrongLockInProgress [static] |
const LockMethodData user_lockmethod [static] |
{
AccessExclusiveLock,
LockConflicts,
lock_mode_names,
&Dummy_trace
}
1.7.1