diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/storage/lmgr.h | 5 | ||||
| -rw-r--r-- | src/include/storage/lock.h | 55 |
2 files changed, 35 insertions, 25 deletions
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h index e983880706..cdbf8ad406 100644 --- a/src/include/storage/lmgr.h +++ b/src/include/storage/lmgr.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.48 2005/04/30 19:03:33 tgl Exp $ + * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.49 2005/06/14 22:15:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -49,7 +49,8 @@ extern void LockRelation(Relation relation, LOCKMODE lockmode); extern bool ConditionalLockRelation(Relation relation, LOCKMODE lockmode); extern void UnlockRelation(Relation relation, LOCKMODE lockmode); -extern void LockRelationForSession(LockRelId *relid, LOCKMODE lockmode); +extern void LockRelationForSession(LockRelId *relid, bool istemprel, + LOCKMODE lockmode); extern void UnlockRelationForSession(LockRelId *relid, LOCKMODE lockmode); /* Lock a relation for extension */ diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h index 63b69e4125..a471ff32a3 100644 --- a/src/include/storage/lock.h +++ b/src/include/storage/lock.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.87 2005/05/29 22:45:02 tgl Exp $ + * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.88 2005/06/14 22:15:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -212,6 +212,10 @@ typedef struct LOCKTAG * 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 { @@ -235,7 +239,7 @@ typedef struct LOCK /* - * We may have several different transactions holding or awaiting locks + * 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. @@ -244,14 +248,11 @@ typedef struct LOCK * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination * of a lockable object and a holder/waiter for that object. * - * There are two possible kinds of proclock owners: a transaction (identified - * both by the PGPROC of the backend running it, and the xact's own ID) and - * a session (identified by backend PGPROC, with XID = InvalidTransactionId). - * - * Currently, session proclocks are used for user locks and for cross-xact - * locks obtained for VACUUM. Note that a single backend can hold locks - * under several different XIDs at once (including session locks). We treat - * such locks as never conflicting (a backend can never block itself). + * 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 @@ -259,6 +260,10 @@ typedef struct LOCK * 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 @@ -269,7 +274,6 @@ typedef struct PROCLOCKTAG { SHMEM_OFFSET lock; /* link to per-lockable-object information */ SHMEM_OFFSET proc; /* link to PGPROC of owning backend */ - TransactionId xid; /* xact ID, or InvalidTransactionId */ } PROCLOCKTAG; typedef struct PROCLOCK @@ -279,9 +283,9 @@ typedef struct PROCLOCK /* data */ LOCKMASK holdMask; /* bitmask for lock types currently held */ - SHM_QUEUE lockLink; /* list link for lock's list of proclocks */ - SHM_QUEUE procLink; /* list link for process's list of - * proclocks */ + 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) \ @@ -299,15 +303,16 @@ typedef struct PROCLOCK typedef struct LOCALLOCKTAG { LOCKTAG lock; /* identifies the lockable object */ - TransactionId xid; /* xact ID, or InvalidTransactionId */ LOCKMODE mode; /* lock mode for this table entry */ } LOCALLOCKTAG; typedef struct LOCALLOCKOWNER { /* - * Note: owner can be NULL to indicate a non-transactional lock. Must - * use a forward struct reference to avoid circularity. + * 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; int nLocks; /* # of times held by this owner */ @@ -321,6 +326,7 @@ typedef struct LOCALLOCK /* data */ LOCK *lock; /* associated LOCK object in shared mem */ PROCLOCK *proclock; /* associated PROCLOCK object in shmem */ + bool isTempObject; /* true if lock is on a temporary object */ int nLocks; /* total number of times lock is held */ int numLockOwners; /* # of relevant ResourceOwners */ int maxLockOwners; /* allocated size of array */ @@ -366,17 +372,20 @@ extern LOCKMETHODID LockMethodTableInit(const char *tabName, const LOCKMASK *conflictsP, int numModes, int maxBackends); extern LOCKMETHODID LockMethodTableRename(LOCKMETHODID lockmethodid); -extern LockAcquireResult LockAcquire(LOCKMETHODID lockmethodid, LOCKTAG *locktag, - TransactionId xid, LOCKMODE lockmode, bool dontWait); +extern LockAcquireResult LockAcquire(LOCKMETHODID lockmethodid, + LOCKTAG *locktag, + bool isTempObject, + LOCKMODE lockmode, + bool sessionLock, + bool dontWait); extern bool LockRelease(LOCKMETHODID lockmethodid, LOCKTAG *locktag, - TransactionId xid, LOCKMODE lockmode); -extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allxids); + LOCKMODE lockmode, bool sessionLock); +extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks); extern void LockReleaseCurrentOwner(void); extern void LockReassignCurrentOwner(void); extern int LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, - LOCK *lock, PROCLOCK *proclock, PGPROC *proc, - int *myHolding); + LOCK *lock, PROCLOCK *proclock, PGPROC *proc); extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode); extern void GrantAwaitedLock(void); extern void RemoveFromWaitQueue(PGPROC *proc); |