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Use the standard lock manager to establish priority order when there

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is contention for a tuple-level lock.  This solves the problem of a
would-be exclusive locker being starved out by an indefinite succession
of share-lockers.  Per recent discussion with Alvaro.
This commit is contained in:
Tom Lane
2005-04-30 19:03:33 +00:00
parent 47458f8c2f
commit 93b2477278
3 changed files with 351 additions and 92 deletions
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19
src/include/storage/lmgr.h
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@@ -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 1.47 2005/04/29 22:28:24 tgl Exp $
* $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.48 2005/04/30 19:03:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -17,6 +17,7 @@
#include "storage/lock.h"
#include "utils/rel.h"
/* These are the valid values of type LOCKMODE: */
/* NoLock is not a lock mode, but a flag value meaning "don't get a lock" */
@@ -60,9 +61,25 @@ extern void LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
extern bool ConditionalLockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
extern void UnlockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
/* Lock a tuple (see heap_lock_tuple before assuming you understand this) */
extern void LockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
extern void UnlockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
/* Lock an XID (used to wait for a transaction to finish) */
extern void XactLockTableInsert(TransactionId xid);
extern void XactLockTableDelete(TransactionId xid);
extern void XactLockTableWait(TransactionId xid);
/* Lock a general object (other than a relation) of the current database */
extern void LockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
LOCKMODE lockmode);
extern void UnlockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
LOCKMODE lockmode);
/* Lock a shared-across-databases object (other than a relation) */
extern void LockSharedObject(Oid classid, Oid objid, uint16 objsubid,
LOCKMODE lockmode);
extern void UnlockSharedObject(Oid classid, Oid objid, uint16 objsubid,
LOCKMODE lockmode);
#endif /* LMGR_H */