Initial MVCC code.

New code for locking buffer' context.

15 files changed, 118 insertions, 129 deletions

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 0c756e0beb..e883c7f0a5 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: heapam.h,v 1.39 1998/11/27 19:33:31 vadim Exp $
+ * $Id: heapam.h,v 1.40 1998/12/15 12:46:44 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,6 +42,7 @@ typedef struct HeapAccessStatisticsData
 	int			global_insert;
 	int			global_delete;
 	int			global_replace;
+	int			global_mark4update;
 	int			global_markpos;
 	int			global_restrpos;
 	int			global_BufferGetRelation;
@@ -64,6 +65,7 @@ typedef struct HeapAccessStatisticsData
 	int			local_insert;
 	int			local_delete;
 	int			local_replace;
+	int			local_mark4update;
 	int			local_markpos;
 	int			local_restrpos;
 	int			local_BufferGetRelation;
@@ -253,9 +255,10 @@ extern void heap_endscan(HeapScanDesc scan);
 extern HeapTuple heap_getnext(HeapScanDesc scandesc, int backw);
 extern void heap_fetch(Relation relation, Snapshot snapshot, HeapTuple tup, Buffer *userbuf);
 extern Oid	heap_insert(Relation relation, HeapTuple tup);
-extern int	heap_delete(Relation relation, ItemPointer tid);
-extern int heap_replace(Relation relation, ItemPointer otid,
-			 HeapTuple tup);
+extern int	heap_delete(Relation relation, ItemPointer tid, ItemPointer ctid);
+extern int	heap_replace(Relation relation, ItemPointer otid, HeapTuple tup,
+							ItemPointer ctid);
+extern int	heap_mark4update(Relation relation, HeapTuple tup, Buffer *userbuf);
 extern void heap_markpos(HeapScanDesc scan);
 extern void heap_restrpos(HeapScanDesc scan);
 
@@ -281,9 +284,4 @@ HeapTuple	heap_addheader(uint32 natts, int structlen, char *structure);
 extern void PrintHeapAccessStatistics(HeapAccessStatistics stats);
 extern void initam(void);
 
-/* hio.c */
-extern void RelationPutHeapTuple(Relation relation, BlockNumber blockIndex,
-					 HeapTuple tuple);
-extern void RelationPutHeapTupleAtEnd(Relation relation, HeapTuple tuple);
-
 #endif	 /* HEAPAM_H */
diff --git a/src/include/access/hio.h b/src/include/access/hio.h
index caa5380083..eb8a955b4d 100644
--- a/src/include/access/hio.h
+++ b/src/include/access/hio.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: hio.h,v 1.8 1998/09/01 04:34:13 momjian Exp $
+ * $Id: hio.h,v 1.9 1998/12/15 12:46:45 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,8 +17,8 @@
 #include <utils/rel.h>
 
 
-extern void RelationPutHeapTuple(Relation relation, BlockNumber blockIndex,
-					 HeapTuple tuple);
+extern void RelationPutHeapTuple(Relation relation, Buffer buffer, 
+									HeapTuple tuple);
 extern void RelationPutHeapTupleAtEnd(Relation relation, HeapTuple tuple);
 
 #endif	 /* HIO_H */
diff --git a/src/include/access/htup.h b/src/include/access/htup.h
index 56197048ba..06c62a9a4d 100644
--- a/src/include/access/htup.h
+++ b/src/include/access/htup.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: htup.h,v 1.11 1998/11/27 19:33:31 vadim Exp $
+ * $Id: htup.h,v 1.12 1998/12/15 12:46:46 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -116,6 +116,7 @@ typedef HeapTupleData *HeapTuple;
 #define HEAP_XMIN_INVALID		0x0200	/* t_xmin invalid/aborted */
 #define HEAP_XMAX_COMMITTED		0x0400	/* t_xmax committed */
 #define HEAP_XMAX_INVALID		0x0800	/* t_xmax invalid/aborted */
+#define HEAP_MARKED_FOR_UPDATE	0x1000	/* marked for UPDATE */
 
 #define HEAP_XACT_MASK			0x0F00	/* */
 
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index e4c1e0a88c..6b0aae443f 100644
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: xact.h,v 1.17 1998/10/08 18:30:23 momjian Exp $
+ * $Id: xact.h,v 1.18 1998/12/15 12:46:47 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,6 +38,8 @@ typedef struct TransactionStateData
 #define XACT_REPEATABLE_READ	2		/* not implemented */
 #define XACT_SERIALIZED			3
 
+extern int	XactIsoLevel;
+
 /* ----------------
  *		transaction states
  * ----------------
diff --git a/src/include/catalog/pg_am.h b/src/include/catalog/pg_am.h
index 3106ffa7cc..bc3b9da1de 100644
--- a/src/include/catalog/pg_am.h
+++ b/src/include/catalog/pg_am.h
@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_am.h,v 1.9 1998/09/01 04:34:47 momjian Exp $
+ * $Id: pg_am.h,v 1.10 1998/12/15 12:46:49 vadim Exp $
  *
  * NOTES
  *		the genbki.sh script reads this file and generates .bki
@@ -106,6 +106,7 @@ DESCR("");
 #define BTREE_AM_OID 403
 DATA(insert OID = 405 (  hash PGUID "o"  1 1 hashgettuple hashinsert hashdelete - - - - hashbeginscan hashrescan hashendscan hashmarkpos hashrestrpos - - hashbuild - - ));
 DESCR("");
+#define HASH_AM_OID 405
 DATA(insert OID = 783 (  gist PGUID "o" 100 7 gistgettuple gistinsert gistdelete - - - - gistbeginscan gistrescan gistendscan gistmarkpos gistrestrpos - - gistbuild - - ));
 DESCR("");
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index c96e05e393..c657375241 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_class.h,v 1.25 1998/09/10 15:32:31 vadim Exp $
+ * $Id: pg_class.h,v 1.26 1998/12/15 12:46:50 vadim Exp $
  *
  * NOTES
  *	  ``pg_relation'' is being replaced by ``pg_class''.  currently
@@ -144,6 +144,8 @@ DATA(insert OID = 1264 (  pg_variable 90	  PGUID 0 0 0 f t s 2  0 0 0 0 0 f f _n
 DESCR("");
 DATA(insert OID = 1269 (  pg_log  99		  PGUID 0 0 0 f t s 1  0 0 0 0 0 f f _null_ ));
 DESCR("");
+DATA(insert OID = 376  (  pg_xactlock  0 	  PGUID 0 0 0 f t s 1  0 0 0 0 0 f f _null_ ));
+DESCR("");
 DATA(insert OID = 1215 (  pg_attrdef 109	  PGUID 0 0 0 t t r 4  0 0 0 0 0 f f _null_ ));
 DESCR("");
 DATA(insert OID = 1216 (  pg_relcheck 110	  PGUID 0 0 0 t t r 4  0 0 0 0 0 f f _null_ ));
@@ -164,6 +166,9 @@ DESCR("");
 #define RelOid_pg_relcheck		1216
 #define RelOid_pg_trigger		1219
 
+/* Xact lock pseudo-table */
+#define XactLockTableId			376
+
 #define		  RELKIND_INDEX			  'i'		/* secondary index */
 #define		  RELKIND_LOBJECT		  'l'		/* large objects */
 #define		  RELKIND_RELATION		  'r'		/* cataloged heap */
diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index 3cc0fdcc06..b52c81dc72 100644
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -12,6 +12,7 @@
 #include "access/tupdesc.h"
 #include "access/htup.h"
 #include "nodes/parsenodes.h"
+#include "nodes/execnodes.h"
 #include "utils/rel.h"
 
 typedef uint32 TriggerEvent;
@@ -65,9 +66,9 @@ extern void RelationRemoveTriggers(Relation rel);
 
 extern HeapTuple ExecBRInsertTriggers(Relation rel, HeapTuple tuple);
 extern void ExecARInsertTriggers(Relation rel, HeapTuple tuple);
-extern bool ExecBRDeleteTriggers(Relation rel, ItemPointer tupleid);
-extern void ExecARDeleteTriggers(Relation rel, ItemPointer tupleid);
-extern HeapTuple ExecBRUpdateTriggers(Relation rel, ItemPointer tupleid, HeapTuple tuple);
-extern void ExecARUpdateTriggers(Relation rel, ItemPointer tupleid, HeapTuple tuple);
+extern bool ExecBRDeleteTriggers(EState *estate, ItemPointer tupleid);
+extern void ExecARDeleteTriggers(EState *estate, ItemPointer tupleid);
+extern HeapTuple ExecBRUpdateTriggers(EState *estate, ItemPointer tupleid, HeapTuple tuple);
+extern void ExecARUpdateTriggers(EState *estate, ItemPointer tupleid, HeapTuple tuple);
 
 #endif	 /* TRIGGER_H */
diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 61f567b6d3..383204c3f0 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: buf_internals.h,v 1.26 1998/09/01 04:38:10 momjian Exp $
+ * $Id: buf_internals.h,v 1.27 1998/12/15 12:46:55 vadim Exp $
  *
  * NOTE
  *		If BUFFERPAGE0 is defined, then 0 will be used as a
@@ -83,32 +83,6 @@ struct buftag
  *		Dbname, relname, dbid, and relid are enough to determine where
  *		to put the buffer, for all storage managers.
  */
-
-#define PADDED_SBUFDESC_SIZE	128
-
-/* DO NOT CHANGE THIS NEXT STRUCTURE:
-   It is used only to get padding information for the real sbufdesc structure
-   It should match the sbufdesc structure exactly except for a missing sb_pad
-*/
-struct sbufdesc_unpadded
-{
-	Buffer		freeNext;
-	Buffer		freePrev;
-	SHMEM_OFFSET data;
-	BufferTag	tag;
-	int			buf_id;
-	BufFlags	flags;
-	unsigned	refcount;
-#ifdef HAS_TEST_AND_SET
-	slock_t		io_in_progress_lock;
-#endif	 /* HAS_TEST_AND_SET */
-	char		sb_dbname[NAMEDATALEN];
-
-	/* NOTE NO PADDING OF THE MEMBER HERE */
-	char		sb_relname[NAMEDATALEN];
-};
-
-/* THE REAL STRUCTURE - the structure above must match it, minus sb_pad */
 struct sbufdesc
 {
 	Buffer		freeNext;		/* link for freelist chain */
@@ -125,32 +99,26 @@ struct sbufdesc
 #ifdef HAS_TEST_AND_SET
 	/* can afford a dedicated lock if test-and-set locks are available */
 	slock_t		io_in_progress_lock;
+	slock_t		cntx_lock;		/* to lock access to page context */
 #endif	 /* HAS_TEST_AND_SET */
+	unsigned	r_locks;		/* # of shared locks */
+	bool		ri_lock;		/* read-intent lock */
+	bool		w_lock;			/* context exclusively locked */
 
 	char		sb_dbname[NAMEDATALEN]; /* name of db in which buf belongs */
-
-	/*
-	 * I padded this structure to a power of 2 (PADDED_SBUFDESC_SIZE)
-	 * because BufferDescriptorGetBuffer is called a billion times and it
-	 * does an C pointer subtraction (i.e., "x - y" -> array index of x
-	 * relative to y, which is calculated using division by struct size).
-	 * Integer ".div" hits you for 35 cycles, as opposed to a 1-cycle
-	 * "sra" ... this hack cut 10% off of the time to create the Wisconsin
-	 * database! It eats up more shared memory, of course, but we're
-	 * (allegedly) going to make some of these types bigger soon anyway...
-	 * -pma 1/2/93
-	 */
-
-	/*
-	 * please, don't take the sizeof() this member and use it for
-	 * something important
-	 */
-
-	char		sb_relname[NAMEDATALEN +		/* name of reln */
-				PADDED_SBUFDESC_SIZE - sizeof(struct sbufdesc_unpadded)];
+	char		sb_relname[NAMEDATALEN];/* name of reln */
 };
 
 /*
+ * Buffer lock infos in BufferLocks below.
+ * We have to free these locks in elog(ERROR)...
+ */
+#define	BL_IO_IN_PROGRESS	(1 << 0)	/* unimplemented */
+#define	BL_R_LOCK			(1 << 1)
+#define	BL_RI_LOCK			(1 << 2)
+#define	BL_W_LOCK			(1 << 3)
+
+/*
  *	mao tracing buffer allocation
  */
 
@@ -201,6 +169,7 @@ extern BufferDesc *BufferDescriptors;
 extern BufferBlock BufferBlocks;
 extern long *PrivateRefCount;
 extern long *LastRefCount;
+extern bits8 *BufferLocks;
 extern long *CommitInfoNeedsSave;
 extern SPINLOCK BufMgrLock;
 
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 1948e813ee..22f66c2295 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: bufmgr.h,v 1.23 1998/10/08 18:30:43 momjian Exp $
+ * $Id: bufmgr.h,v 1.24 1998/12/15 12:46:56 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -74,6 +74,14 @@ extern int	ShowPinTrace;
 #define BUFFER_LATE_WRITE		1		/* delayed write: mark as DIRTY */
 
 /*
+ * Buffer context lock modes
+ */
+#define	BUFFER_LOCK_UNLOCK		0
+#define	BUFFER_LOCK_SHARE		1
+#define	BUFFER_LOCK_EXCLUSIVE	2
+
+
+/*
  * BufferIsValid --
  *		True iff the refcnt of the local buffer is > 0
  * Note:
@@ -155,4 +163,7 @@ extern void BufferRefCountRestore(int *refcountsave);
 extern int	SetBufferWriteMode(int mode);
 extern void SetBufferCommitInfoNeedsSave(Buffer buffer);
 
+extern void UnlockBuffers(void);
+extern void LockBuffer(Buffer buffer, int mode);
+
 #endif	 /* !defined(BufMgrIncluded) */
diff --git a/src/include/storage/ipc.h b/src/include/storage/ipc.h
index 4733b34bbc..2163aa79d5 100644
--- a/src/include/storage/ipc.h
+++ b/src/include/storage/ipc.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: ipc.h,v 1.30 1998/09/01 04:38:16 momjian Exp $
+ * $Id: ipc.h,v 1.31 1998/12/15 12:46:57 vadim Exp $
  *
  * NOTES
  *	  This file is very architecture-specific.	This stuff should actually
@@ -186,6 +186,8 @@ typedef enum _LockId_
 		((key == PrivateIPCKey) ? key : 11 + (key))
 #define IPCKeyGetWaitIOSemaphoreKey(key) \
 		((key == PrivateIPCKey) ? key : 12 + (key))
+#define IPCKeyGetWaitCLSemaphoreKey(key) \
+		((key == PrivateIPCKey) ? key : 13 + (key))
 
 /* --------------------------
  * NOTE: This macro must always give the highest numbered key as every backend
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h
index 4082811bcc..a85ba1e8ff 100644
--- a/src/include/storage/lmgr.h
+++ b/src/include/storage/lmgr.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: lmgr.h,v 1.15 1998/09/01 04:38:23 momjian Exp $
+ * $Id: lmgr.h,v 1.16 1998/12/15 12:46:57 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,64 +17,48 @@
 #include <utils/rel.h>
 #include <catalog/catname.h>
 
-/*
- * This was moved from pladt.h for the new lock manager.  Want to obsolete
- * all of the old code.
- */
+#define AccessShareLock			1		/* SELECT */
+#define RowShareLock			2		/* SELECT FOR UPDATE */
+#define RowExclusiveLock		3		/* INSERT, UPDATE, DELETE */
+#define ShareLock				4
+#define ShareRowExclusiveLock	5
+#define ExclusiveLock			6
+#define AccessExclusiveLock		7
+
+#define ExtendLock				8
+
+extern LOCKMETHOD LockTableId;
+
+
 typedef struct LockRelId
 {
 	Oid			relId;			/* a relation identifier */
 	Oid			dbId;			/* a database identifier */
 }			LockRelId;
 
-#ifdef LowLevelLocking
 typedef struct LockInfoData
 {
 	LockRelId	lockRelId;
-	bool		lockHeld[MAX_LOCKMODES];		/* on table level */
 } LockInfoData;
 
-#else
-typedef struct LockInfoData
-{
-	LockRelId	lockRelId;
-} LockInfoData;
-
-#endif
-
 typedef LockInfoData *LockInfo;
 
 #define LockInfoIsValid(lockinfo)	PointerIsValid(lockinfo)
 
+extern LOCKMETHOD InitLockTable(void);
 extern void RelationInitLockInfo(Relation relation);
-extern void RelationSetLockForDescriptorOpen(Relation relation);
-extern void RelationSetLockForRead(Relation relation);
-extern void RelationUnsetLockForRead(Relation relation);
-extern void RelationSetLockForWrite(Relation relation);
-extern void RelationUnsetLockForWrite(Relation relation);
 
-/* used in vaccum.c */
-extern void RelationSetLockForWritePage(Relation relation,
-							ItemPointer itemPointer);
+extern void LockRelation(Relation relation, LOCKMODE lockmode);
+extern void UnlockRelation(Relation relation, LOCKMODE lockmode);
 
-/* used in nbtpage.c, hashpage.c */
-extern void RelationSetSingleWLockPage(Relation relation,
-						   ItemPointer itemPointer);
-extern void RelationUnsetSingleWLockPage(Relation relation,
-							 ItemPointer itemPointer);
-extern void RelationSetSingleRLockPage(Relation relation,
-						   ItemPointer itemPointer);
-extern void RelationUnsetSingleRLockPage(Relation relation,
-							 ItemPointer itemPointer);
-extern void RelationSetRIntentLock(Relation relation);
-extern void RelationUnsetRIntentLock(Relation relation);
-extern void RelationSetWIntentLock(Relation relation);
-extern void RelationUnsetWIntentLock(Relation relation);
+/* this is for indices */
+extern void LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
+extern void UnlockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode);
 
-/* single.c */
-extern bool SingleLockReln(LockInfo lockinfo, LOCKMODE lockmode, int action);
-extern bool SingleLockPage(LockInfo lockinfo, ItemPointer tidPtr,
-			   LOCKMODE lockmode, int action);
+/* and this is for transactions */
+extern void XactLockTableInsert(TransactionId xid);
+extern void XactLockTableDelete(TransactionId xid);
+extern void XactLockTableWait(TransactionId xid);
 
 /* proc.c */
 extern void InitProcGlobal(IPCKey key);
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 329aa758a7..9c803ef8a1 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: lock.h,v 1.19 1998/10/08 18:30:45 momjian Exp $
+ * $Id: lock.h,v 1.20 1998/12/15 12:46:58 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,11 +42,7 @@ typedef int LOCKMODE;
 typedef int LOCKMETHOD;
 
 /* MAX_LOCKMODES cannot be larger than the bits in MASK */
-#ifdef LowLevelLocking
 #define MAX_LOCKMODES	9
-#else
-#define MAX_LOCKMODES	6
-#endif
 
 /*
  * MAX_LOCK_METHODS corresponds to the number of spin locks allocated in
@@ -69,7 +65,11 @@ typedef struct LTAG
 {
 	Oid			relId;
 	Oid			dbId;
-	ItemPointerData tupleId;
+	union
+	{
+		BlockNumber		blkno;
+		TransactionId	xid;
+	}			objId;
 	uint16		lockmethod;		/* needed by user locks */
 } LOCKTAG;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 4a62fac18a..914d934524 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: proc.h,v 1.15 1998/09/01 04:38:31 momjian Exp $
+ * $Id: proc.h,v 1.16 1998/12/15 12:46:59 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -44,11 +44,9 @@ typedef struct proc
 	TransactionId xid;			/* transaction currently being executed by
 								 * this proc */
 
-#ifdef LowLevelLocking
 	TransactionId xmin;			/* minimal running XID as it was when we
 								 * were starting our xact: vacuum must not
 								 * remove tuples deleted by xid >= xmin ! */
-#endif
 
 	LOCK	   *waitLock;		/* Lock we're sleeping on */
 	int			token;			/* info for proc wakeup routines */
diff --git a/src/include/storage/s_lock.h b/src/include/storage/s_lock.h
index d47f5ab53b..aa20a328bd 100644
--- a/src/include/storage/s_lock.h
+++ b/src/include/storage/s_lock.h
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/include/storage/s_lock.h,v 1.56 1998/10/31 02:06:08 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/include/storage/s_lock.h,v 1.57 1998/12/15 12:46:59 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -68,6 +68,8 @@
 
 #include "storage/ipc.h"
 
+extern void s_lock_sleep(unsigned spin);
+
 #if defined(HAS_TEST_AND_SET)
 
 
diff --git a/src/include/utils/tqual.h b/src/include/utils/tqual.h
index 3d2f8531f4..cb15a60ca0 100644
--- a/src/include/utils/tqual.h
+++ b/src/include/utils/tqual.h
@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: tqual.h,v 1.15 1998/11/27 19:33:35 vadim Exp $
+ * $Id: tqual.h,v 1.16 1998/12/15 12:47:01 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,17 +18,20 @@
 
 typedef struct SnapshotData
 {
-	TransactionId xmin;			/* XID < xmin are visible to me */
-	TransactionId xmax;			/* XID > xmax are invisible to me */
-	TransactionId *xip;			/* array of xacts in progress */
+	TransactionId	xmin;			/* XID < xmin are visible to me */
+	TransactionId	xmax;			/* XID > xmax are invisible to me */
+	TransactionId  *xip;			/* array of xacts in progress */
 }			SnapshotData;
 
 typedef SnapshotData *Snapshot;
 
-#define IsSnapshotNow(snapshot)		((Snapshot) snapshot == (Snapshot) 0x0)
-#define IsSnapshotSelf(snapshot)	((Snapshot) snapshot == (Snapshot) 0x1)
 #define SnapshotNow					((Snapshot) 0x0)
 #define SnapshotSelf				((Snapshot) 0x1)
+extern	Snapshot					SnapshotDirty;
+
+#define IsSnapshotNow(snapshot)		((Snapshot) snapshot == SnapshotNow)
+#define IsSnapshotSelf(snapshot)	((Snapshot) snapshot == SnapshotSelf)
+#define IsSnapshotDirty(snapshot)	((Snapshot) snapshot == SnapshotDirty)
 
 extern TransactionId HeapSpecialTransactionId;
 extern CommandId HeapSpecialCommandId;
@@ -49,7 +52,11 @@ extern CommandId HeapSpecialCommandId;
 		(IsSnapshotSelf(snapshot) || heapisoverride()) ? \
 			HeapTupleSatisfiesItself((tuple)->t_data) \
 		: \
-			HeapTupleSatisfiesNow((tuple)->t_data) \
+			((IsSnapshotDirty(snapshot)) ? \
+				HeapTupleSatisfiesDirty((tuple)->t_data) \
+			: \
+				HeapTupleSatisfiesNow((tuple)->t_data) \
+			) \
 	) \
 )
 
@@ -71,10 +78,18 @@ extern CommandId HeapSpecialCommandId;
 	) \
 )
 
-extern bool HeapTupleSatisfiesItself(HeapTupleHeader tuple);
-extern bool HeapTupleSatisfiesNow(HeapTupleHeader tuple);
+#define	HeapTupleMayBeUpdated		0
+#define	HeapTupleInvisible			1
+#define HeapTupleSelfUpdated		2
+#define HeapTupleUpdated			3
+#define HeapTupleBeingUpdated		4
 
-extern void setheapoverride(bool on);
+extern bool		HeapTupleSatisfiesItself(HeapTupleHeader tuple);
+extern bool		HeapTupleSatisfiesNow(HeapTupleHeader tuple);
+extern bool		HeapTupleSatisfiesDirty(HeapTupleHeader tuple);
+extern int		HeapTupleSatisfiesUpdate(HeapTuple tuple);
 
+extern void setheapoverride(bool on);
+extern Snapshot GetSnapshotData(bool serialized);
 
 #endif	 /* TQUAL_H */