Ensure that all TransactionId comparisons are encapsulated in macros

(TransactionIdPrecedes, TransactionIdFollows, etc).  First step on the
way to transaction ID wrap solution ...

src/backend/access/common/heaptuple.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.72 2001/06/12 05:55:49 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.73 2001/08/23 23:06:37 tgl Exp $
  *
  * NOTES
  *	  The old interface functions have been converted to macros
@@ -441,20 +441,16 @@ heap_getsysattr(HeapTuple tup, int attnum, bool *isnull)
 			result = ObjectIdGetDatum(tup->t_data->t_oid);
 			break;
 		case MinTransactionIdAttributeNumber:
-			/* XXX should have a TransactionIdGetDatum macro */
+			result = TransactionIdGetDatum(tup->t_data->t_xmin);
-			result = (Datum) (tup->t_data->t_xmin);
 			break;
 		case MinCommandIdAttributeNumber:
-			/* XXX should have a CommandIdGetDatum macro */
+			result = CommandIdGetDatum(tup->t_data->t_cmin);
-			result = (Datum) (tup->t_data->t_cmin);
 			break;
 		case MaxTransactionIdAttributeNumber:
-			/* XXX should have a TransactionIdGetDatum macro */
+			result = TransactionIdGetDatum(tup->t_data->t_xmax);
-			result = (Datum) (tup->t_data->t_xmax);
 			break;
 		case MaxCommandIdAttributeNumber:
-			/* XXX should have a CommandIdGetDatum macro */
+			result = CommandIdGetDatum(tup->t_data->t_cmax);
-			result = (Datum) (tup->t_data->t_cmax);
 			break;
 		case TableOidAttributeNumber:
 			result = ObjectIdGetDatum(tup->t_tableOid);

src/backend/access/heap/heapam.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.124 2001/08/10 18:57:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.125 2001/08/23 23:06:37 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1206,7 +1206,7 @@ l1:
 		 * update then some other xaction could update this tuple before
 		 * we got to this point.
 		 */
-		if (tp.t_data->t_xmax != xwait)
+		if (!TransactionIdEquals(tp.t_data->t_xmax, xwait))
 			goto l1;
 		if (!(tp.t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
@@ -1398,7 +1398,7 @@ l2:
 		 * update then some other xaction could update this tuple before
 		 * we got to this point.
 		 */
-		if (oldtup.t_data->t_xmax != xwait)
+		if (!TransactionIdEquals(oldtup.t_data->t_xmax, xwait))
 			goto l2;
 		if (!(oldtup.t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
@@ -1694,7 +1694,7 @@ l3:
 		 * update then some other xaction could update this tuple before
 		 * we got to this point.
 		 */
-		if (tuple->t_data->t_xmax != xwait)
+		if (!TransactionIdEquals(tuple->t_data->t_xmax, xwait))
 			goto l3;
 		if (!(tuple->t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
@@ -2123,7 +2123,8 @@ heap_xlog_insert(bool redo, XLogRecPtr lsn, XLogRecord *record)
 		htup->t_hoff = xlhdr.t_hoff;
 		htup->t_xmin = record->xl_xid;
 		htup->t_cmin = FirstCommandId;
-		htup->t_xmax = htup->t_cmax = 0;
+		htup->t_xmax = InvalidTransactionId;
+		htup->t_cmax = FirstCommandId;
 		htup->t_infomask = HEAP_XMAX_INVALID | xlhdr.mask;
 
 		offnum = PageAddItem(page, (Item) htup, newlen, offnum,
@@ -2310,7 +2311,8 @@ newsame:;
 		{
 			htup->t_xmin = record->xl_xid;
 			htup->t_cmin = FirstCommandId;
-			htup->t_xmax = htup->t_cmax = 0;
+			htup->t_xmax = InvalidTransactionId;
+			htup->t_cmax = FirstCommandId;
 			htup->t_infomask = HEAP_XMAX_INVALID | xlhdr.mask;
 		}
 
@@ -2366,7 +2368,7 @@ _heap_unlock_tuple(void *data)
 
 	htup = (HeapTupleHeader) PageGetItem(page, lp);
 
-	if (htup->t_xmax != GetCurrentTransactionId() ||
+	if (!TransactionIdEquals(htup->t_xmax, GetCurrentTransactionId()) ||
 		htup->t_cmax != GetCurrentCommandId())
 		elog(STOP, "_heap_unlock_tuple: invalid xmax/cmax in rollback");
 	htup->t_infomask &= ~HEAP_XMAX_UNLOGGED;

src/backend/access/nbtree/nbtinsert.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.84 2001/07/15 22:48:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.85 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -149,8 +149,8 @@ top:
 /*
  *	_bt_check_unique() -- Check for violation of unique index constraint
  *
- * Returns NullTransactionId if there is no conflict, else an xact ID we
+ * Returns InvalidTransactionId if there is no conflict, else an xact ID
- * must wait for to see if it commits a conflicting tuple.	If an actual
+ * we must wait for to see if it commits a conflicting tuple.	If an actual
  * conflict is detected, no return --- just elog().
  */
 static TransactionId
@@ -275,7 +275,7 @@ _bt_check_unique(Relation rel, BTItem btitem, Relation heapRel,
 	if (nbuf != InvalidBuffer)
 		_bt_relbuf(rel, nbuf);
 
-	return NullTransactionId;
+	return InvalidTransactionId;
 }
 
 /*----------

src/backend/access/transam/transam.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.45 2001/07/12 04:11:13 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.46 2001/08/23 23:06:37 tgl Exp $
  *
  * NOTES
  *	  This file contains the high level access-method interface to the
@@ -44,7 +44,7 @@ Relation	LogRelation = (Relation) NULL;
  *		Single-item cache for results of TransactionLogTest.
  * ----------------
  */
-static TransactionId cachedTestXid = NullTransactionId;
+static TransactionId cachedTestXid = InvalidTransactionId;
 static XidStatus	cachedTestXidStatus;
 
 /* ----------------
@@ -333,18 +333,19 @@ InitializeTransactionLog(void)
 
 	/*
 	 * if we have a virgin database, we initialize the log relation by
-	 * committing the AmiTransactionId and we initialize the
+	 * committing the BootstrapTransactionId and we initialize the
 	 * variable relation by setting the next available transaction id to
-	 * FirstTransactionId.  OID initialization happens as a side
+	 * FirstNormalTransactionId.  OID initialization happens as a side
 	 * effect of bootstrapping in varsup.c.
 	 */
 	SpinAcquire(OidGenLockId);
-	if (!TransactionIdDidCommit(AmiTransactionId))
+	if (!TransactionIdDidCommit(BootstrapTransactionId))
 	{
-		TransactionLogUpdate(AmiTransactionId, XID_COMMIT);
+		TransactionLogUpdate(BootstrapTransactionId, XID_COMMIT);
 		Assert(!IsUnderPostmaster &&
-			   ShmemVariableCache->nextXid <= FirstTransactionId);
+			   TransactionIdEquals(ShmemVariableCache->nextXid,
-		ShmemVariableCache->nextXid = FirstTransactionId;
+								   FirstNormalTransactionId));
+		ShmemVariableCache->nextXid = FirstNormalTransactionId;
 	}
 	else if (RecoveryCheckingEnabled())
 	{

src/backend/access/transam/varsup.c

@@ -6,7 +6,7 @@
  * Copyright (c) 2000, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.43 2001/08/10 18:57:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.44 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -41,7 +41,7 @@ GetNewTransactionId(TransactionId *xid)
 	 */
 	if (AMI_OVERRIDE)
 	{
-		*xid = AmiTransactionId;
+		*xid = BootstrapTransactionId;
 		return;
 	}
 
@@ -49,7 +49,7 @@ GetNewTransactionId(TransactionId *xid)
 
 	*xid = ShmemVariableCache->nextXid;
 
-	(ShmemVariableCache->nextXid)++;
+	TransactionIdAdvance(ShmemVariableCache->nextXid);
 
 	/*
 	 * Must set MyProc->xid before releasing XidGenLock.  This ensures that
@@ -89,7 +89,7 @@ ReadNewTransactionId(TransactionId *xid)
 	 */
 	if (AMI_OVERRIDE)
 	{
-		*xid = AmiTransactionId;
+		*xid = BootstrapTransactionId;
 		return;
 	}
 

src/backend/access/transam/xid.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: xid.c,v 1.31 2001/07/12 04:11:13 tgl Exp $
+ *	$Id: xid.c,v 1.32 2001/08/23 23:06:37 tgl Exp $
  *
  * OLD COMMENTS
  * XXX WARNING
@@ -23,11 +23,8 @@
 
 #include "access/xact.h"
 
-/*
+#define PG_GETARG_TRANSACTIONID(n)	DatumGetTransactionId(PG_GETARG_DATUM(n))
- * TransactionId is typedef'd as uint32, so...
+#define PG_RETURN_TRANSACTIONID(x)	return TransactionIdGetDatum(x)
- */
-#define PG_GETARG_TRANSACTIONID(n)	PG_GETARG_UINT32(n)
-#define PG_RETURN_TRANSACTIONID(x)	PG_RETURN_UINT32(x)
 
 
 Datum
@@ -42,7 +39,6 @@ Datum
 xidout(PG_FUNCTION_ARGS)
 {
 	TransactionId transactionId = PG_GETARG_TRANSACTIONID(0);
-
 	/* maximum 32 bit unsigned integer representation takes 10 chars */
 	char	   *representation = palloc(11);
 

src/backend/access/transam/xlog.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.73 2001/08/10 18:57:33 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.74 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2349,7 +2349,7 @@ BootStrapXLOG(void)
 	checkPoint.redo.xrecoff = SizeOfXLogPHD;
 	checkPoint.undo = checkPoint.redo;
 	checkPoint.ThisStartUpID = 0;
-	checkPoint.nextXid = FirstTransactionId;
+	checkPoint.nextXid = FirstNormalTransactionId;
 	checkPoint.nextOid = BootstrapObjectIdData;
 	checkPoint.time = time(NULL);
 
@@ -2508,7 +2508,7 @@ StartupXLOG(void)
 		 wasShutdown ? "TRUE" : "FALSE");
 	elog(LOG, "next transaction id: %u; next oid: %u",
 		 checkPoint.nextXid, checkPoint.nextOid);
-	if (checkPoint.nextXid < FirstTransactionId)
+	if (!TransactionIdIsNormal(checkPoint.nextXid))
 		elog(STOP, "invalid next transaction id");
 
 	ShmemVariableCache->nextXid = checkPoint.nextXid;
@@ -2550,8 +2550,10 @@ StartupXLOG(void)
 		if (XLByteLT(checkPoint.redo, RecPtr))
 			record = ReadRecord(&(checkPoint.redo), STOP, buffer);
 		else
-/* read past CheckPoint record */
+		{
+			/* read past CheckPoint record */
 			record = ReadRecord(NULL, LOG, buffer);
+		}
 
 		if (record != NULL)
 		{
@@ -2560,8 +2562,13 @@ StartupXLOG(void)
 				 ReadRecPtr.xlogid, ReadRecPtr.xrecoff);
 			do
 			{
-				if (record->xl_xid >= ShmemVariableCache->nextXid)
+				/* nextXid must be beyond record's xid */
-					ShmemVariableCache->nextXid = record->xl_xid + 1;
+				if (TransactionIdFollowsOrEquals(record->xl_xid,
+												 ShmemVariableCache->nextXid))
+				{
+					ShmemVariableCache->nextXid = record->xl_xid;
+					TransactionIdAdvance(ShmemVariableCache->nextXid);
+				}
 				if (XLOG_DEBUG)
 				{
 					char		buf[8192];
@@ -3101,7 +3108,8 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
 
 		memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
 		/* In an ONLINE checkpoint, treat the counters like NEXTOID */
-		if (ShmemVariableCache->nextXid < checkPoint.nextXid)
+		if (TransactionIdPrecedes(ShmemVariableCache->nextXid,
+								  checkPoint.nextXid))
 			ShmemVariableCache->nextXid = checkPoint.nextXid;
 		if (ShmemVariableCache->nextOid < checkPoint.nextOid)
 		{

src/backend/access/transam/xlogutils.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlogutils.c,v 1.16 2001/06/29 21:08:24 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlogutils.c,v 1.17 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -76,7 +76,7 @@ XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr,
 	htup = (HeapTupleHeader) PageGetItem(page, lp);
 
 	Assert(PageGetSUI(page) == ThisStartUpID);
-	if (htup->t_xmin != xid || htup->t_cmin != cid)
+	if (!TransactionIdEquals(htup->t_xmin, xid) || htup->t_cmin != cid)
 	{
 		UnlockAndReleaseBuffer(buffer);
 		return (-1);

src/backend/commands/trigger.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.95 2001/08/10 18:57:34 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.96 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2078,7 +2078,8 @@ DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event,
 			 * foreign referenced key value that's changing now has been
 			 * updated once before in this transaction.
 			 */
-			if (oldtup->t_data->t_xmin != GetCurrentTransactionId())
+			if (!TransactionIdEquals(oldtup->t_data->t_xmin,
+									 GetCurrentTransactionId()))
 				prev_event = NULL;
 			else
 				prev_event =
@@ -2212,7 +2213,8 @@ DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event,
 			 * possibly referenced key value has changed in this
 			 * transaction.
 			 */
-			if (oldtup->t_data->t_xmin != GetCurrentTransactionId())
+			if (!TransactionIdEquals(oldtup->t_data->t_xmin,
+									 GetCurrentTransactionId()))
 				break;
 
 			/*

src/backend/postmaster/pgstat.c

@@ -16,7 +16,7 @@
  *
  *	Copyright (c) 2001, PostgreSQL Global Development Group
  *
- *	$Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.6 2001/08/05 02:06:50 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.7 2001/08/23 23:06:37 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -500,10 +500,10 @@ pgstat_vacuum_tabstat(void)
 	 * If not done for this transaction, read the statistics collector
 	 * stats file into some hash tables.
 	 */
-	if (pgStatDBHashXact != GetCurrentTransactionId())
+	if (!TransactionIdEquals(pgStatDBHashXact, GetCurrentTransactionId()))
 	{
 		pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, 
-						&pgStatBeTable, &pgStatNumBackends);
+							  &pgStatBeTable, &pgStatNumBackends);
 		pgStatDBHashXact = GetCurrentTransactionId();
 	}
 
@@ -916,10 +916,10 @@ pgstat_fetch_stat_dbentry(Oid dbid)
 	 * stats file into some hash tables. Be careful with the read_statsfile()
 	 * call below!
 	 */
-	if (pgStatDBHashXact != GetCurrentTransactionId())
+	if (!TransactionIdEquals(pgStatDBHashXact, GetCurrentTransactionId()))
 	{
 		pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, 
-						&pgStatBeTable, &pgStatNumBackends);
+							  &pgStatBeTable, &pgStatNumBackends);
 		pgStatDBHashXact = GetCurrentTransactionId();
 	}
 
@@ -956,10 +956,10 @@ pgstat_fetch_stat_tabentry(Oid relid)
 	 * stats file into some hash tables. Be careful with the read_statsfile()
 	 * call below!
 	 */
-	if (pgStatDBHashXact != GetCurrentTransactionId())
+	if (!TransactionIdEquals(pgStatDBHashXact, GetCurrentTransactionId()))
 	{
 		pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, 
-						&pgStatBeTable, &pgStatNumBackends);
+							  &pgStatBeTable, &pgStatNumBackends);
 		pgStatDBHashXact = GetCurrentTransactionId();
 	}
 
@@ -997,10 +997,10 @@ pgstat_fetch_stat_tabentry(Oid relid)
 PgStat_StatBeEntry *
 pgstat_fetch_stat_beentry(int beid)
 {
-	if (pgStatDBHashXact != GetCurrentTransactionId())
+	if (!TransactionIdEquals(pgStatDBHashXact, GetCurrentTransactionId()))
 	{
 		pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, 
-						&pgStatBeTable, &pgStatNumBackends);
+							  &pgStatBeTable, &pgStatNumBackends);
 		pgStatDBHashXact = GetCurrentTransactionId();
 	}
 
@@ -1021,10 +1021,10 @@ pgstat_fetch_stat_beentry(int beid)
 int
 pgstat_fetch_stat_numbackends(void)
 {
-	if (pgStatDBHashXact != GetCurrentTransactionId())
+	if (!TransactionIdEquals(pgStatDBHashXact, GetCurrentTransactionId()))
 	{
 		pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, 
-						&pgStatBeTable, &pgStatNumBackends);
+							  &pgStatBeTable, &pgStatNumBackends);
 		pgStatDBHashXact = GetCurrentTransactionId();
 	}
 

src/backend/storage/ipc/sinval.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.37 2001/07/16 22:43:34 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.38 2001/08/23 23:06:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -241,12 +241,12 @@ GetXmaxRecent(TransactionId *XmaxRecent)
 			/* Fetch xid just once - see GetNewTransactionId */
 			TransactionId xid = proc->xid;
 
-			if (! TransactionIdIsSpecial(xid))
+			if (TransactionIdIsNormal(xid))
 			{
 				if (TransactionIdPrecedes(xid, result))
 					result = xid;
 				xid = proc->xmin;
-				if (! TransactionIdIsSpecial(xid))
+				if (TransactionIdIsNormal(xid))
 					if (TransactionIdPrecedes(xid, result))
 						result = xid;
 			}
@@ -347,8 +347,8 @@ GetSnapshotData(bool serializable)
 			 * treat them as running anyway.
 			 */
 			if (proc == MyProc ||
-				TransactionIdIsSpecial(xid) ||
+				! TransactionIdIsNormal(xid) ||
-				! TransactionIdPrecedes(xid, snapshot->xmax))
+				TransactionIdFollowsOrEquals(xid, snapshot->xmax))
 				continue;
 
 			if (TransactionIdPrecedes(xid, snapshot->xmin))
@@ -364,7 +364,7 @@ GetSnapshotData(bool serializable)
 	SpinRelease(SInvalLock);
 
 	/* Serializable snapshot must be computed before any other... */
-	Assert(MyProc->xmin != InvalidTransactionId);
+	Assert(TransactionIdIsValid(MyProc->xmin));
 
 	snapshot->xcnt = count;
 	return snapshot;

src/backend/storage/lmgr/lock.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.91 2001/07/09 22:18:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.92 2001/08/23 23:06:38 tgl Exp $
  *
  * NOTES
  *	  Outside modules can create a lock table and acquire/release
@@ -1277,7 +1277,7 @@ LockReleaseAll(LOCKMETHOD lockmethod, PROC *proc,
 			goto next_item;
 
 		/* If not allxids, ignore items that are of the wrong xid */
-		if (!allxids && xid != holder->tag.xid)
+		if (!allxids && !TransactionIdEquals(xid, holder->tag.xid))
 			goto next_item;
 
 		HOLDER_PRINT("LockReleaseAll", holder);

src/backend/utils/time/tqual.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.39 2001/07/16 22:43:34 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.40 2001/08/23 23:06:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -531,15 +531,15 @@ HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 	 * when...
 	 */
 
-	if (tuple->t_xmin >= snapshot->xmax)
+	if (TransactionIdFollowsOrEquals(tuple->t_xmin, snapshot->xmax))
 		return false;
-	if (tuple->t_xmin >= snapshot->xmin)
+	if (TransactionIdFollowsOrEquals(tuple->t_xmin, snapshot->xmin))
 	{
 		uint32		i;
 
 		for (i = 0; i < snapshot->xcnt; i++)
 		{
-			if (tuple->t_xmin == snapshot->xip[i])
+			if (TransactionIdEquals(tuple->t_xmin, snapshot->xip[i]))
 				return false;
 		}
 	}
@@ -571,15 +571,15 @@ HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 		tuple->t_infomask |= HEAP_XMAX_COMMITTED;
 	}
 
-	if (tuple->t_xmax >= snapshot->xmax)
+	if (TransactionIdFollowsOrEquals(tuple->t_xmax, snapshot->xmax))
 		return true;
-	if (tuple->t_xmax >= snapshot->xmin)
+	if (TransactionIdFollowsOrEquals(tuple->t_xmax, snapshot->xmin))
 	{
 		uint32		i;
 
 		for (i = 0; i < snapshot->xcnt; i++)
 		{
-			if (tuple->t_xmax == snapshot->xip[i])
+			if (TransactionIdEquals(tuple->t_xmax, snapshot->xip[i]))
 				return true;
 		}
 	}

src/include/access/transam.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: transam.h,v 1.37 2001/08/10 18:57:39 tgl Exp $
+ * $Id: transam.h,v 1.38 2001/08/23 23:06:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,29 +24,37 @@
  * 128 bytes of pg_log available for special purposes such as version number
  * storage.  (Currently, we do not actually use them for anything.)
  *
- * AmiTransactionId is the XID for "bootstrap" operations.  It should always
+ * BootstrapTransactionId is the XID for "bootstrap" operations.  It should
- * be considered valid.
+ * always be considered valid.
  *
- * FirstTransactionId is the first "normal" transaction id.
+ * FirstNormalTransactionId is the first "normal" transaction id.
  * ----------------
  */
-#define NullTransactionId		((TransactionId) 0)
+#define InvalidTransactionId		((TransactionId) 0)
-#define DisabledTransactionId	((TransactionId) 1)
+#define DisabledTransactionId		((TransactionId) 1)
-#define AmiTransactionId		((TransactionId) 512)
+#define BootstrapTransactionId		((TransactionId) 512)
-#define FirstTransactionId		((TransactionId) 514)
+#define FirstNormalTransactionId	((TransactionId) 514)
 
 /* ----------------
  *		transaction ID manipulation macros
  * ----------------
  */
-#define TransactionIdIsValid(xid)		((bool) ((xid) != NullTransactionId))
+#define TransactionIdIsValid(xid)		((xid) != InvalidTransactionId)
-#define TransactionIdIsSpecial(xid)		((bool) ((xid) < FirstTransactionId))
+#define TransactionIdIsNormal(xid)		((xid) >= FirstNormalTransactionId)
-#define TransactionIdEquals(id1, id2)	((bool) ((id1) == (id2)))
+#define TransactionIdEquals(id1, id2)			((id1) == (id2))
-#define TransactionIdPrecedes(id1, id2)	((bool) ((id1) < (id2)))
+#define TransactionIdPrecedes(id1, id2)			((id1) < (id2))
-#define TransactionIdStore(xid, dest)	\
+#define TransactionIdPrecedesOrEquals(id1, id2)	((id1) <= (id2))
-	(*((TransactionId*) (dest)) = (TransactionId) (xid))
+#define TransactionIdFollows(id1, id2)			((id1) > (id2))
-#define StoreInvalidTransactionId(dest) \
+#define TransactionIdFollowsOrEquals(id1, id2)	((id1) >= (id2))
-	(*((TransactionId*) (dest)) = NullTransactionId)
+#define TransactionIdStore(xid, dest)	(*(dest) = (xid))
+#define StoreInvalidTransactionId(dest)	(*(dest) = InvalidTransactionId)
+/* advance a transaction ID variable, handling wraparound correctly */
+#define TransactionIdAdvance(dest)	\
+	do { \
+		(dest)++; \
+		if ((dest) < FirstNormalTransactionId) \
+			(dest) = FirstNormalTransactionId; \
+	} while(0)
 
 /* ----------------
  *		transaction status values

src/include/c.h

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: c.h,v 1.97 2001/07/11 22:12:43 momjian Exp $
+ * $Id: c.h,v 1.98 2001/08/23 23:06:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -330,11 +330,9 @@ typedef Oid RegProcedure;
 
 typedef uint32 TransactionId;
 
-#define InvalidTransactionId	0
-
 typedef uint32 CommandId;
 
-#define FirstCommandId	0
+#define FirstCommandId	((CommandId) 0)
 
 /*
  * Array indexing support

src/include/postgres.h

@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1995, Regents of the University of California
  *
- * $Id: postgres.h,v 1.50 2001/08/10 18:57:41 tgl Exp $
+ * $Id: postgres.h,v 1.51 2001/08/23 23:06:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -261,6 +261,34 @@ typedef Datum *DatumPtr;
 
 #define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X))
 
+/*
+ * DatumGetTransactionId
+ *		Returns transaction identifier value of a datum.
+ */
+
+#define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X))
+
+/*
+ * TransactionIdGetDatum
+ *		Returns datum representation for a transaction identifier.
+ */
+
+#define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X)))
+
+/*
+ * DatumGetCommandId
+ *		Returns command identifier value of a datum.
+ */
+
+#define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X))
+
+/*
+ * CommandIdGetDatum
+ *		Returns datum representation for a command identifier.
+ */
+
+#define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X))
+
 /*
  * DatumGetPointer
  *		Returns pointer value of a datum.

src/include/utils/tqual.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: tqual.h,v 1.32 2001/07/12 04:11:13 tgl Exp $
+ * $Id: tqual.h,v 1.33 2001/08/23 23:06:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,7 +57,7 @@ extern bool ReferentialIntegritySnapshotOverride;
  */
 #define HeapTupleSatisfiesVisibility(tuple, snapshot) \
 ( \
-	TransactionIdEquals((tuple)->t_data->t_xmax, AmiTransactionId) ? \
+	TransactionIdEquals((tuple)->t_data->t_xmax, BootstrapTransactionId) ? \
 		false \
 	: \
 	( \