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71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* lwlock.h
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* Lightweight lock manager
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*
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*
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* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: lwlock.h,v 1.8 2003/08/04 02:40:14 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LWLOCK_H
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#define LWLOCK_H
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/*
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* We have a number of predefined LWLocks, plus a bunch of LWLocks that are
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* dynamically assigned (for shared buffers). The LWLock structures live
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* in shared memory (since they contain shared data) and are identified by
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* values of this enumerated type. We abuse the notion of an enum somewhat
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* by allowing values not listed in the enum declaration to be assigned.
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* The extra value MaxDynamicLWLock is there to keep the compiler from
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* deciding that the enum can be represented as char or short ...
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*/
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typedef enum LWLockId
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{
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BufMgrLock,
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LockMgrLock,
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OidGenLock,
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XidGenLock,
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ShmemIndexLock,
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SInvalLock,
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FreeSpaceLock,
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MMCacheLock,
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WALInsertLock,
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WALWriteLock,
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ControlFileLock,
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CheckpointLock,
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RelCacheInitLock,
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NumFixedLWLocks, /* must be last except for
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* MaxDynamicLWLock */
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MaxDynamicLWLock = 1000000000
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} LWLockId;
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typedef enum LWLockMode
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{
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LW_EXCLUSIVE,
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LW_SHARED
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} LWLockMode;
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#ifdef LOCK_DEBUG
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extern bool Trace_lwlocks;
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#endif
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extern LWLockId LWLockAssign(void);
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extern void LWLockAcquire(LWLockId lockid, LWLockMode mode);
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extern bool LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode);
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extern void LWLockRelease(LWLockId lockid);
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extern void LWLockReleaseAll(void);
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extern int NumLWLocks(void);
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extern int LWLockShmemSize(void);
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extern void CreateLWLocks(void);
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#endif /* LWLOCK_H */
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