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Diffstat (limited to 'src/include/storage/lock.h')
| -rw-r--r-- | src/include/storage/lock.h | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h new file mode 100644 index 0000000..a5286fa --- /dev/null +++ b/src/include/storage/lock.h @@ -0,0 +1,616 @@ +/*------------------------------------------------------------------------- + * + * lock.h + * POSTGRES low-level lock mechanism + * + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/lock.h + * + *------------------------------------------------------------------------- + */ +#ifndef LOCK_H_ +#define LOCK_H_ + +#ifdef FRONTEND +#error "lock.h may not be included from frontend code" +#endif + +#include "storage/backendid.h" +#include "storage/lockdefs.h" +#include "storage/lwlock.h" +#include "storage/shmem.h" +#include "utils/timestamp.h" + +/* struct PGPROC is declared in proc.h, but must forward-reference it */ +typedef struct PGPROC PGPROC; + +typedef struct PROC_QUEUE +{ + SHM_QUEUE links; /* head of list of PGPROC objects */ + int size; /* number of entries in list */ +} PROC_QUEUE; + +/* GUC variables */ +extern int max_locks_per_xact; + +#ifdef LOCK_DEBUG +extern int Trace_lock_oidmin; +extern bool Trace_locks; +extern bool Trace_userlocks; +extern int Trace_lock_table; +extern bool Debug_deadlocks; +#endif /* LOCK_DEBUG */ + + +/* + * Top-level transactions are identified by VirtualTransactionIDs comprising + * PGPROC fields backendId and lxid. For recovered prepared transactions, the + * LocalTransactionId is an ordinary XID; LOCKTAG_VIRTUALTRANSACTION never + * refers to that kind. These are guaranteed unique over the short term, but + * will be reused after a database restart or XID wraparound; hence they + * should never be stored on disk. + * + * Note that struct VirtualTransactionId can not be assumed to be atomically + * assignable as a whole. However, type LocalTransactionId is assumed to + * be atomically assignable, and the backend ID doesn't change often enough + * to be a problem, so we can fetch or assign the two fields separately. + * We deliberately refrain from using the struct within PGPROC, to prevent + * coding errors from trying to use struct assignment with it; instead use + * GET_VXID_FROM_PGPROC(). + */ +typedef struct +{ + BackendId backendId; /* backendId from PGPROC */ + LocalTransactionId localTransactionId; /* lxid from PGPROC */ +} VirtualTransactionId; + +#define InvalidLocalTransactionId 0 +#define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId) +#define VirtualTransactionIdIsValid(vxid) \ + (LocalTransactionIdIsValid((vxid).localTransactionId)) +#define VirtualTransactionIdIsRecoveredPreparedXact(vxid) \ + ((vxid).backendId == InvalidBackendId) +#define VirtualTransactionIdEquals(vxid1, vxid2) \ + ((vxid1).backendId == (vxid2).backendId && \ + (vxid1).localTransactionId == (vxid2).localTransactionId) +#define SetInvalidVirtualTransactionId(vxid) \ + ((vxid).backendId = InvalidBackendId, \ + (vxid).localTransactionId = InvalidLocalTransactionId) +#define GET_VXID_FROM_PGPROC(vxid, proc) \ + ((vxid).backendId = (proc).backendId, \ + (vxid).localTransactionId = (proc).lxid) + +/* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */ +#define MAX_LOCKMODES 10 + +#define LOCKBIT_ON(lockmode) (1 << (lockmode)) +#define LOCKBIT_OFF(lockmode) (~(1 << (lockmode))) + + +/* + * This data structure defines the locking semantics associated with a + * "lock method". The semantics specify the meaning of each lock mode + * (by defining which lock modes it conflicts with). + * All of this data is constant and is kept in const tables. + * + * numLockModes -- number of lock modes (READ,WRITE,etc) that + * are defined in this lock method. Must be less than MAX_LOCKMODES. + * + * conflictTab -- this is an array of bitmasks showing lock + * mode conflicts. conflictTab[i] is a mask with the j-th bit + * turned on if lock modes i and j conflict. Lock modes are + * numbered 1..numLockModes; conflictTab[0] is unused. + * + * lockModeNames -- ID strings for debug printouts. + * + * trace_flag -- pointer to GUC trace flag for this lock method. (The + * GUC variable is not constant, but we use "const" here to denote that + * it can't be changed through this reference.) + */ +typedef struct LockMethodData +{ + int numLockModes; + const LOCKMASK *conflictTab; + const char *const *lockModeNames; + const bool *trace_flag; +} LockMethodData; + +typedef const LockMethodData *LockMethod; + +/* + * Lock methods are identified by LOCKMETHODID. (Despite the declaration as + * uint16, we are constrained to 256 lockmethods by the layout of LOCKTAG.) + */ +typedef uint16 LOCKMETHODID; + +/* These identify the known lock methods */ +#define DEFAULT_LOCKMETHOD 1 +#define USER_LOCKMETHOD 2 + +/* + * LOCKTAG is the key information needed to look up a LOCK item in the + * lock hashtable. A LOCKTAG value uniquely identifies a lockable object. + * + * The LockTagType enum defines the different kinds of objects we can lock. + * We can handle up to 256 different LockTagTypes. + */ +typedef enum LockTagType +{ + LOCKTAG_RELATION, /* whole relation */ + LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */ + LOCKTAG_DATABASE_FROZEN_IDS, /* pg_database.datfrozenxid */ + LOCKTAG_PAGE, /* one page of a relation */ + LOCKTAG_TUPLE, /* one physical tuple */ + LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */ + LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */ + LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */ + LOCKTAG_OBJECT, /* non-relation database object */ + LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */ + LOCKTAG_ADVISORY /* advisory user locks */ +} LockTagType; + +#define LOCKTAG_LAST_TYPE LOCKTAG_ADVISORY + +extern const char *const LockTagTypeNames[]; + +/* + * The LOCKTAG struct is defined with malice aforethought to fit into 16 + * bytes with no padding. Note that this would need adjustment if we were + * to widen Oid, BlockNumber, or TransactionId to more than 32 bits. + * + * We include lockmethodid in the locktag so that a single hash table in + * shared memory can store locks of different lockmethods. + */ +typedef struct LOCKTAG +{ + uint32 locktag_field1; /* a 32-bit ID field */ + uint32 locktag_field2; /* a 32-bit ID field */ + uint32 locktag_field3; /* a 32-bit ID field */ + uint16 locktag_field4; /* a 16-bit ID field */ + uint8 locktag_type; /* see enum LockTagType */ + uint8 locktag_lockmethodid; /* lockmethod indicator */ +} LOCKTAG; + +/* + * These macros define how we map logical IDs of lockable objects into + * the physical fields of LOCKTAG. Use these to set up LOCKTAG values, + * rather than accessing the fields directly. Note multiple eval of target! + */ + +/* ID info for a relation is DB OID + REL OID; DB OID = 0 if shared */ +#define SET_LOCKTAG_RELATION(locktag,dboid,reloid) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = (reloid), \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_RELATION, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* same ID info as RELATION */ +#define SET_LOCKTAG_RELATION_EXTEND(locktag,dboid,reloid) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = (reloid), \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* ID info for frozen IDs is DB OID */ +#define SET_LOCKTAG_DATABASE_FROZEN_IDS(locktag,dboid) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = 0, \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_DATABASE_FROZEN_IDS, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* ID info for a page is RELATION info + BlockNumber */ +#define SET_LOCKTAG_PAGE(locktag,dboid,reloid,blocknum) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = (reloid), \ + (locktag).locktag_field3 = (blocknum), \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_PAGE, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* ID info for a tuple is PAGE info + OffsetNumber */ +#define SET_LOCKTAG_TUPLE(locktag,dboid,reloid,blocknum,offnum) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = (reloid), \ + (locktag).locktag_field3 = (blocknum), \ + (locktag).locktag_field4 = (offnum), \ + (locktag).locktag_type = LOCKTAG_TUPLE, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* ID info for a transaction is its TransactionId */ +#define SET_LOCKTAG_TRANSACTION(locktag,xid) \ + ((locktag).locktag_field1 = (xid), \ + (locktag).locktag_field2 = 0, \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_TRANSACTION, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* ID info for a virtual transaction is its VirtualTransactionId */ +#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \ + ((locktag).locktag_field1 = (vxid).backendId, \ + (locktag).locktag_field2 = (vxid).localTransactionId, \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* + * ID info for a speculative insert is TRANSACTION info + + * its speculative insert counter. + */ +#define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag,xid,token) \ + ((locktag).locktag_field1 = (xid), \ + (locktag).locktag_field2 = (token), \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +/* + * ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID + * + * Note: object ID has same representation as in pg_depend and + * pg_description, but notice that we are constraining SUBID to 16 bits. + * Also, we use DB OID = 0 for shared objects such as tablespaces. + */ +#define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \ + ((locktag).locktag_field1 = (dboid), \ + (locktag).locktag_field2 = (classoid), \ + (locktag).locktag_field3 = (objoid), \ + (locktag).locktag_field4 = (objsubid), \ + (locktag).locktag_type = LOCKTAG_OBJECT, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + +#define SET_LOCKTAG_ADVISORY(locktag,id1,id2,id3,id4) \ + ((locktag).locktag_field1 = (id1), \ + (locktag).locktag_field2 = (id2), \ + (locktag).locktag_field3 = (id3), \ + (locktag).locktag_field4 = (id4), \ + (locktag).locktag_type = LOCKTAG_ADVISORY, \ + (locktag).locktag_lockmethodid = USER_LOCKMETHOD) + + +/* + * Per-locked-object lock information: + * + * tag -- uniquely identifies the object being locked + * grantMask -- bitmask for all lock types currently granted on this object. + * waitMask -- bitmask for all lock types currently awaited on this object. + * procLocks -- list of PROCLOCK objects for this lock. + * waitProcs -- queue of processes waiting for this lock. + * requested -- count of each lock type currently requested on the lock + * (includes requests already granted!!). + * nRequested -- total requested locks of all types. + * granted -- count of each lock type currently granted on the lock. + * nGranted -- total granted locks of all types. + * + * Note: these counts count 1 for each backend. Internally to a backend, + * there may be multiple grabs on a particular lock, but this is not reflected + * into shared memory. + */ +typedef struct LOCK +{ + /* hash key */ + LOCKTAG tag; /* unique identifier of lockable object */ + + /* data */ + LOCKMASK grantMask; /* bitmask for lock types already granted */ + LOCKMASK waitMask; /* bitmask for lock types awaited */ + SHM_QUEUE procLocks; /* list of PROCLOCK objects assoc. with lock */ + PROC_QUEUE waitProcs; /* list of PGPROC objects waiting on lock */ + int requested[MAX_LOCKMODES]; /* counts of requested locks */ + int nRequested; /* total of requested[] array */ + int granted[MAX_LOCKMODES]; /* counts of granted locks */ + int nGranted; /* total of granted[] array */ +} LOCK; + +#define LOCK_LOCKMETHOD(lock) ((LOCKMETHODID) (lock).tag.locktag_lockmethodid) +#define LOCK_LOCKTAG(lock) ((LockTagType) (lock).tag.locktag_type) + + +/* + * We may have several different backends holding or awaiting locks + * on the same lockable object. We need to store some per-holder/waiter + * information for each such holder (or would-be holder). This is kept in + * a PROCLOCK struct. + * + * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the + * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination + * of a lockable object and a holder/waiter for that object. (We can use + * pointers here because the PROCLOCKTAG need only be unique for the lifespan + * of the PROCLOCK, and it will never outlive the lock or the proc.) + * + * Internally to a backend, it is possible for the same lock to be held + * for different purposes: the backend tracks transaction locks separately + * from session locks. However, this is not reflected in the shared-memory + * state: we only track which backend(s) hold the lock. This is OK since a + * backend can never block itself. + * + * The holdMask field shows the already-granted locks represented by this + * proclock. Note that there will be a proclock object, possibly with + * zero holdMask, for any lock that the process is currently waiting on. + * Otherwise, proclock objects whose holdMasks are zero are recycled + * as soon as convenient. + * + * releaseMask is workspace for LockReleaseAll(): it shows the locks due + * to be released during the current call. This must only be examined or + * set by the backend owning the PROCLOCK. + * + * Each PROCLOCK object is linked into lists for both the associated LOCK + * object and the owning PGPROC object. Note that the PROCLOCK is entered + * into these lists as soon as it is created, even if no lock has yet been + * granted. A PGPROC that is waiting for a lock to be granted will also be + * linked into the lock's waitProcs queue. + */ +typedef struct PROCLOCKTAG +{ + /* NB: we assume this struct contains no padding! */ + LOCK *myLock; /* link to per-lockable-object information */ + PGPROC *myProc; /* link to PGPROC of owning backend */ +} PROCLOCKTAG; + +typedef struct PROCLOCK +{ + /* tag */ + PROCLOCKTAG tag; /* unique identifier of proclock object */ + + /* data */ + PGPROC *groupLeader; /* proc's lock group leader, or proc itself */ + LOCKMASK holdMask; /* bitmask for lock types currently held */ + LOCKMASK releaseMask; /* bitmask for lock types to be released */ + SHM_QUEUE lockLink; /* list link in LOCK's list of proclocks */ + SHM_QUEUE procLink; /* list link in PGPROC's list of proclocks */ +} PROCLOCK; + +#define PROCLOCK_LOCKMETHOD(proclock) \ + LOCK_LOCKMETHOD(*((proclock).tag.myLock)) + +/* + * Each backend also maintains a local hash table with information about each + * lock it is currently interested in. In particular the local table counts + * the number of times that lock has been acquired. This allows multiple + * requests for the same lock to be executed without additional accesses to + * shared memory. We also track the number of lock acquisitions per + * ResourceOwner, so that we can release just those locks belonging to a + * particular ResourceOwner. + * + * When holding a lock taken "normally", the lock and proclock fields always + * point to the associated objects in shared memory. However, if we acquired + * the lock via the fast-path mechanism, the lock and proclock fields are set + * to NULL, since there probably aren't any such objects in shared memory. + * (If the lock later gets promoted to normal representation, we may eventually + * update our locallock's lock/proclock fields after finding the shared + * objects.) + * + * Caution: a locallock object can be left over from a failed lock acquisition + * attempt. In this case its lock/proclock fields are untrustworthy, since + * the shared lock object is neither held nor awaited, and hence is available + * to be reclaimed. If nLocks > 0 then these pointers must either be valid or + * NULL, but when nLocks == 0 they should be considered garbage. + */ +typedef struct LOCALLOCKTAG +{ + LOCKTAG lock; /* identifies the lockable object */ + LOCKMODE mode; /* lock mode for this table entry */ +} LOCALLOCKTAG; + +typedef struct LOCALLOCKOWNER +{ + /* + * Note: if owner is NULL then the lock is held on behalf of the session; + * otherwise it is held on behalf of my current transaction. + * + * Must use a forward struct reference to avoid circularity. + */ + struct ResourceOwnerData *owner; + int64 nLocks; /* # of times held by this owner */ +} LOCALLOCKOWNER; + +typedef struct LOCALLOCK +{ + /* tag */ + LOCALLOCKTAG tag; /* unique identifier of locallock entry */ + + /* data */ + uint32 hashcode; /* copy of LOCKTAG's hash value */ + LOCK *lock; /* associated LOCK object, if any */ + PROCLOCK *proclock; /* associated PROCLOCK object, if any */ + int64 nLocks; /* total number of times lock is held */ + int numLockOwners; /* # of relevant ResourceOwners */ + int maxLockOwners; /* allocated size of array */ + LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */ + bool holdsStrongLockCount; /* bumped FastPathStrongRelationLocks */ + bool lockCleared; /* we read all sinval msgs for lock */ +} LOCALLOCK; + +#define LOCALLOCK_LOCKMETHOD(llock) ((llock).tag.lock.locktag_lockmethodid) +#define LOCALLOCK_LOCKTAG(llock) ((LockTagType) (llock).tag.lock.locktag_type) + + +/* + * These structures hold information passed from lmgr internals to the lock + * listing user-level functions (in lockfuncs.c). + */ + +typedef struct LockInstanceData +{ + LOCKTAG locktag; /* tag for locked object */ + LOCKMASK holdMask; /* locks held by this PGPROC */ + LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */ + BackendId backend; /* backend ID of this PGPROC */ + LocalTransactionId lxid; /* local transaction ID of this PGPROC */ + TimestampTz waitStart; /* time at which this PGPROC started waiting + * for lock */ + int pid; /* pid of this PGPROC */ + int leaderPid; /* pid of group leader; = pid if no group */ + bool fastpath; /* taken via fastpath? */ +} LockInstanceData; + +typedef struct LockData +{ + int nelements; /* The length of the array */ + LockInstanceData *locks; /* Array of per-PROCLOCK information */ +} LockData; + +typedef struct BlockedProcData +{ + int pid; /* pid of a blocked PGPROC */ + /* Per-PROCLOCK information about PROCLOCKs of the lock the pid awaits */ + /* (these fields refer to indexes in BlockedProcsData.locks[]) */ + int first_lock; /* index of first relevant LockInstanceData */ + int num_locks; /* number of relevant LockInstanceDatas */ + /* PIDs of PGPROCs that are ahead of "pid" in the lock's wait queue */ + /* (these fields refer to indexes in BlockedProcsData.waiter_pids[]) */ + int first_waiter; /* index of first preceding waiter */ + int num_waiters; /* number of preceding waiters */ +} BlockedProcData; + +typedef struct BlockedProcsData +{ + BlockedProcData *procs; /* Array of per-blocked-proc information */ + LockInstanceData *locks; /* Array of per-PROCLOCK information */ + int *waiter_pids; /* Array of PIDs of other blocked PGPROCs */ + int nprocs; /* # of valid entries in procs[] array */ + int maxprocs; /* Allocated length of procs[] array */ + int nlocks; /* # of valid entries in locks[] array */ + int maxlocks; /* Allocated length of locks[] array */ + int npids; /* # of valid entries in waiter_pids[] array */ + int maxpids; /* Allocated length of waiter_pids[] array */ +} BlockedProcsData; + + +/* Result codes for LockAcquire() */ +typedef enum +{ + LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */ + LOCKACQUIRE_OK, /* lock successfully acquired */ + LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */ + LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */ +} LockAcquireResult; + +/* Deadlock states identified by DeadLockCheck() */ +typedef enum +{ + DS_NOT_YET_CHECKED, /* no deadlock check has run yet */ + DS_NO_DEADLOCK, /* no deadlock detected */ + DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */ + DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */ + DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum + * worker */ +} DeadLockState; + +/* + * The lockmgr's shared hash tables are partitioned to reduce contention. + * To determine which partition a given locktag belongs to, compute the tag's + * hash code with LockTagHashCode(), then apply one of these macros. + * NB: NUM_LOCK_PARTITIONS must be a power of 2! + */ +#define LockHashPartition(hashcode) \ + ((hashcode) % NUM_LOCK_PARTITIONS) +#define LockHashPartitionLock(hashcode) \ + (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + \ + LockHashPartition(hashcode)].lock) +#define LockHashPartitionLockByIndex(i) \ + (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock) + +/* + * The deadlock detector needs to be able to access lockGroupLeader and + * related fields in the PGPROC, so we arrange for those fields to be protected + * by one of the lock hash partition locks. Since the deadlock detector + * acquires all such locks anyway, this makes it safe for it to access these + * fields without doing anything extra. To avoid contention as much as + * possible, we map different PGPROCs to different partition locks. The lock + * used for a given lock group is determined by the group leader's pgprocno. + */ +#define LockHashPartitionLockByProc(leader_pgproc) \ + LockHashPartitionLock((leader_pgproc)->pgprocno) + +/* + * function prototypes + */ +extern void InitLocks(void); +extern LockMethod GetLocksMethodTable(const LOCK *lock); +extern LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag); +extern uint32 LockTagHashCode(const LOCKTAG *locktag); +extern bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2); +extern LockAcquireResult LockAcquire(const LOCKTAG *locktag, + LOCKMODE lockmode, + bool sessionLock, + bool dontWait); +extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag, + LOCKMODE lockmode, + bool sessionLock, + bool dontWait, + bool reportMemoryError, + LOCALLOCK **locallockp); +extern void AbortStrongLockAcquire(void); +extern void MarkLockClear(LOCALLOCK *locallock); +extern bool LockRelease(const LOCKTAG *locktag, + LOCKMODE lockmode, bool sessionLock); +extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks); +extern void LockReleaseSession(LOCKMETHODID lockmethodid); +extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks); +extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks); +extern bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode); +#ifdef USE_ASSERT_CHECKING +extern HTAB *GetLockMethodLocalHash(void); +#endif +extern bool LockHasWaiters(const LOCKTAG *locktag, + LOCKMODE lockmode, bool sessionLock); +extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag, + LOCKMODE lockmode, int *countp); +extern void AtPrepare_Locks(void); +extern void PostPrepare_Locks(TransactionId xid); +extern bool LockCheckConflicts(LockMethod lockMethodTable, + LOCKMODE lockmode, + LOCK *lock, PROCLOCK *proclock); +extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode); +extern void GrantAwaitedLock(void); +extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode); +extern Size LockShmemSize(void); +extern LockData *GetLockStatusData(void); +extern BlockedProcsData *GetBlockerStatusData(int blocked_pid); + +extern xl_standby_lock *GetRunningTransactionLocks(int *nlocks); +extern const char *GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode); + +extern void lock_twophase_recover(TransactionId xid, uint16 info, + void *recdata, uint32 len); +extern void lock_twophase_postcommit(TransactionId xid, uint16 info, + void *recdata, uint32 len); +extern void lock_twophase_postabort(TransactionId xid, uint16 info, + void *recdata, uint32 len); +extern void lock_twophase_standby_recover(TransactionId xid, uint16 info, + void *recdata, uint32 len); + +extern DeadLockState DeadLockCheck(PGPROC *proc); +extern PGPROC *GetBlockingAutoVacuumPgproc(void); +extern void DeadLockReport(void) pg_attribute_noreturn(); +extern void RememberSimpleDeadLock(PGPROC *proc1, + LOCKMODE lockmode, + LOCK *lock, + PGPROC *proc2); +extern void InitDeadLockChecking(void); + +extern int LockWaiterCount(const LOCKTAG *locktag); + +#ifdef LOCK_DEBUG +extern void DumpLocks(PGPROC *proc); +extern void DumpAllLocks(void); +#endif + +/* Lock a VXID (used to wait for a transaction to finish) */ +extern void VirtualXactLockTableInsert(VirtualTransactionId vxid); +extern void VirtualXactLockTableCleanup(void); +extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait); + +#endif /* LOCK_H_ */ |