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	are now reported via elog, eliminating the need to test the result code at most call sites. Make it possible for the caller to distinguish a freshly acquired lock from one already held in the current transaction. Use that capability to avoid redundant AcceptInvalidationMessages() calls in LockRelation().
		
			
				
	
	
		
			82 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			82 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * user_locks.c --
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|  *
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|  * This loadable module provides support for user-level long-term
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|  * cooperative locks.
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|  *
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|  * Copyright (C) 1999, Massimo Dal Zotto <dz@cs.unitn.it>
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|  *
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|  * This software is distributed under the GNU General Public License
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|  * either version 2, or (at your option) any later version.
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|  */
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| #include "postgres.h"
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| 
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| #include "miscadmin.h"
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| #include "storage/lmgr.h"
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| #include "storage/proc.h"
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| 
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| #include "user_locks.h"
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| 
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| 
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| #define SET_LOCKTAG_USERLOCK(locktag,id1,id2) \
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| 	((locktag).locktag_field1 = MyDatabaseId, \
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| 	 (locktag).locktag_field2 = (id1), \
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| 	 (locktag).locktag_field3 = (id2), \
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| 	 (locktag).locktag_field4 = 0, \
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| 	 (locktag).locktag_type = LOCKTAG_USERLOCK)
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| 
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| 
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| int
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| user_lock(uint32 id1, uint32 id2, LOCKMODE lockmode)
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| {
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| 	LOCKTAG		tag;
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| 
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| 	SET_LOCKTAG_USERLOCK(tag, id1, id2);
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| 
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| 	return (LockAcquire(USER_LOCKMETHOD, &tag, InvalidTransactionId,
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| 						lockmode, true) != LOCKACQUIRE_NOT_AVAIL);
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| }
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| 
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| int
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| user_unlock(uint32 id1, uint32 id2, LOCKMODE lockmode)
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| {
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| 	LOCKTAG		tag;
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| 
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| 	SET_LOCKTAG_USERLOCK(tag, id1, id2);
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| 
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| 	return LockRelease(USER_LOCKMETHOD, &tag, InvalidTransactionId, lockmode);
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| }
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| 
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| int
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| user_write_lock(uint32 id1, uint32 id2)
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| {
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| 	return user_lock(id1, id2, ExclusiveLock);
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| }
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| 
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| 
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| int
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| user_write_unlock(uint32 id1, uint32 id2)
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| {
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| 	return user_unlock(id1, id2, ExclusiveLock);
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| }
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| 
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| int
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| user_write_lock_oid(Oid oid)
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| {
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| 	return user_lock(0, oid, ExclusiveLock);
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| }
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| 
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| int
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| user_write_unlock_oid(Oid oid)
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| {
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| 	return user_unlock(0, oid, ExclusiveLock);
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| }
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| 
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| int
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| user_unlock_all(void)
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| {
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| 	LockReleaseAll(USER_LOCKMETHOD, true);
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| 
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| 	return true;
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| }
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