From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 21 May 2002 22:05:55 +0000 (+0000)
Subject: Remove global variable scanCommandId in favor of storing a command ID
X-Git-Tag: REL7_3~1506
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=959e61e917a802074e257d4bec13ee04ab4822ff;p=postgresql

Remove global variable scanCommandId in favor of storing a command ID
in snapshots, per my proposal of a few days ago.  Also, tweak heapam.c
routines (heap_insert, heap_update, heap_delete, heap_mark4update) to
be passed the command ID to use, instead of doing GetCurrentCommandID.
For catalog updates they'll still get passed current command ID, but
for updates generated from the main executor they'll get passed the
command ID saved in the snapshot the query is using.  This should fix
some corner cases associated with functions and triggers that advance
current command ID while an outer query is still in progress.
---

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index dac14ac339..a8d7ca0c29 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.134 2002/05/20 23:51:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.135 2002/05/21 22:05:53 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1059,15 +1059,14 @@ heap_get_latest_tid(Relation relation,
 	return tid;
 }
 
-/* ----------------
- *		heap_insert		- insert tuple into a heap
+/*
+ *	heap_insert		- insert tuple into a heap
  *
- *		The assignment of t_min (and thus the others) should be
- *		removed eventually.
- * ----------------
+ * The new tuple is stamped with current transaction ID and the specified
+ * command ID.
  */
 Oid
-heap_insert(Relation relation, HeapTuple tup)
+heap_insert(Relation relation, HeapTuple tup, CommandId cid)
 {
 	Buffer		buffer;
 
@@ -1093,8 +1092,9 @@ heap_insert(Relation relation, HeapTuple tup)
 	}
 
 	TransactionIdStore(GetCurrentTransactionId(), &(tup->t_data->t_xmin));
-	tup->t_data->t_cmin = GetCurrentCommandId();
+	tup->t_data->t_cmin = cid;
 	StoreInvalidTransactionId(&(tup->t_data->t_xmax));
+	tup->t_data->t_cmax = FirstCommandId;
 	tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
 	tup->t_data->t_infomask |= HEAP_XMAX_INVALID;
 	tup->t_tableOid = relation->rd_id;
@@ -1178,6 +1178,19 @@ heap_insert(Relation relation, HeapTuple tup)
 	return tup->t_data->t_oid;
 }
 
+/*
+ *	simple_heap_insert - insert a tuple
+ *
+ * Currently, this routine differs from heap_insert only in supplying
+ * a default command ID.  But it should be used rather than using
+ * heap_insert directly in most places where we are modifying system catalogs.
+ */
+Oid
+simple_heap_insert(Relation relation, HeapTuple tup)
+{
+	return heap_insert(relation, tup, GetCurrentCommandId());
+}
+
 /*
  *	heap_delete		- delete a tuple
  *
@@ -1185,7 +1198,8 @@ heap_insert(Relation relation, HeapTuple tup)
  * concurrent-update conditions.  Use simple_heap_delete instead.
  */
 int
-heap_delete(Relation relation, ItemPointer tid, ItemPointer ctid)
+heap_delete(Relation relation, ItemPointer tid,
+			ItemPointer ctid, CommandId cid)
 {
 	ItemId		lp;
 	HeapTupleData tp;
@@ -1215,7 +1229,7 @@ heap_delete(Relation relation, ItemPointer tid, ItemPointer ctid)
 	tp.t_tableOid = relation->rd_id;
 
 l1:
-	result = HeapTupleSatisfiesUpdate(&tp);
+	result = HeapTupleSatisfiesUpdate(&tp, cid);
 
 	if (result == HeapTupleInvisible)
 	{
@@ -1265,7 +1279,7 @@ l1:
 	START_CRIT_SECTION();
 	/* store transaction information of xact deleting the tuple */
 	TransactionIdStore(GetCurrentTransactionId(), &(tp.t_data->t_xmax));
-	tp.t_data->t_cmax = GetCurrentCommandId();
+	tp.t_data->t_cmax = cid;
 	tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
 							 HEAP_XMAX_INVALID | HEAP_MARKED_FOR_UPDATE);
 	/* XLOG stuff */
@@ -1336,7 +1350,7 @@ simple_heap_delete(Relation relation, ItemPointer tid)
 	ItemPointerData ctid;
 	int			result;
 
-	result = heap_delete(relation, tid, &ctid);
+	result = heap_delete(relation, tid, &ctid, GetCurrentCommandId());
 	switch (result)
 	{
 		case HeapTupleSelfUpdated:
@@ -1356,7 +1370,6 @@ simple_heap_delete(Relation relation, ItemPointer tid)
 			elog(ERROR, "Unknown status %u from heap_delete", result);
 			break;
 	}
-
 }
 
 /*
@@ -1367,7 +1380,7 @@ simple_heap_delete(Relation relation, ItemPointer tid)
  */
 int
 heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
-			ItemPointer ctid)
+			ItemPointer ctid, CommandId cid)
 {
 	ItemId		lp;
 	HeapTupleData oldtup;
@@ -1407,7 +1420,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 	 */
 
 l2:
-	result = HeapTupleSatisfiesUpdate(&oldtup);
+	result = HeapTupleSatisfiesUpdate(&oldtup, cid);
 
 	if (result == HeapTupleInvisible)
 	{
@@ -1457,7 +1470,7 @@ l2:
 	/* Fill in OID and transaction status data for newtup */
 	newtup->t_data->t_oid = oldtup.t_data->t_oid;
 	TransactionIdStore(GetCurrentTransactionId(), &(newtup->t_data->t_xmin));
-	newtup->t_data->t_cmin = GetCurrentCommandId();
+	newtup->t_data->t_cmin = cid;
 	StoreInvalidTransactionId(&(newtup->t_data->t_xmax));
 	newtup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
 	newtup->t_data->t_infomask |= (HEAP_XMAX_INVALID | HEAP_UPDATED);
@@ -1496,7 +1509,7 @@ l2:
 
 		TransactionIdStore(GetCurrentTransactionId(),
 						   &(oldtup.t_data->t_xmax));
-		oldtup.t_data->t_cmax = GetCurrentCommandId();
+		oldtup.t_data->t_cmax = cid;
 		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
 									   HEAP_XMAX_INVALID |
 									   HEAP_MARKED_FOR_UPDATE);
@@ -1588,7 +1601,7 @@ l2:
 	{
 		TransactionIdStore(GetCurrentTransactionId(),
 						   &(oldtup.t_data->t_xmax));
-		oldtup.t_data->t_cmax = GetCurrentCommandId();
+		oldtup.t_data->t_cmax = cid;
 		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
 									   HEAP_XMAX_INVALID |
 									   HEAP_MARKED_FOR_UPDATE);
@@ -1653,7 +1666,7 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
 	ItemPointerData ctid;
 	int			result;
 
-	result = heap_update(relation, otid, tup, &ctid);
+	result = heap_update(relation, otid, tup, &ctid, GetCurrentCommandId());
 	switch (result)
 	{
 		case HeapTupleSelfUpdated:
@@ -1679,7 +1692,8 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
  *	heap_mark4update		- mark a tuple for update
  */
 int
-heap_mark4update(Relation relation, HeapTuple tuple, Buffer *buffer)
+heap_mark4update(Relation relation, HeapTuple tuple, Buffer *buffer,
+				 CommandId cid)
 {
 	ItemPointer tid = &(tuple->t_self);
 	ItemId		lp;
@@ -1704,7 +1718,7 @@ heap_mark4update(Relation relation, HeapTuple tuple, Buffer *buffer)
 	tuple->t_len = ItemIdGetLength(lp);
 
 l3:
-	result = HeapTupleSatisfiesUpdate(tuple);
+	result = HeapTupleSatisfiesUpdate(tuple, cid);
 
 	if (result == HeapTupleInvisible)
 	{
@@ -1758,7 +1772,7 @@ l3:
 
 	/* store transaction information of xact marking the tuple */
 	TransactionIdStore(GetCurrentTransactionId(), &(tuple->t_data->t_xmax));
-	tuple->t_data->t_cmax = GetCurrentCommandId();
+	tuple->t_data->t_cmax = cid;
 	tuple->t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID);
 	tuple->t_data->t_infomask |= HEAP_MARKED_FOR_UPDATE;
 
@@ -2400,9 +2414,8 @@ _heap_unlock_tuple(void *data)
 
 	htup = (HeapTupleHeader) PageGetItem(page, lp);
 
-	if (!TransactionIdEquals(htup->t_xmax, GetCurrentTransactionId()) ||
-		htup->t_cmax != GetCurrentCommandId())
-		elog(PANIC, "_heap_unlock_tuple: invalid xmax/cmax in rollback");
+	if (!TransactionIdEquals(htup->t_xmax, GetCurrentTransactionId()))
+		elog(PANIC, "_heap_unlock_tuple: invalid xmax in rollback");
 	htup->t_infomask &= ~HEAP_XMAX_UNLOGGED;
 	htup->t_infomask |= HEAP_XMAX_INVALID;
 	UnlockAndWriteBuffer(buffer);
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c
index 18bc99982a..9ac1c69c8e 100644
--- a/src/backend/access/heap/tuptoaster.c
+++ b/src/backend/access/heap/tuptoaster.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/tuptoaster.c,v 1.29 2002/05/20 23:51:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/tuptoaster.c,v 1.30 2002/05/21 22:05:53 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -911,7 +911,7 @@ toast_save_datum(Relation rel, Datum value)
 		if (!HeapTupleIsValid(toasttup))
 			elog(ERROR, "Failed to build TOAST tuple");
 
-		heap_insert(toastrel, toasttup);
+		simple_heap_insert(toastrel, toasttup);
 
 		/*
 		 * Create the index entry.	We cheat a little here by not using
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 39e4afeb74..10de2f8a6d 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.122 2002/05/17 20:53:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.123 2002/05/21 22:05:53 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -350,14 +350,6 @@ GetCurrentCommandId(void)
 	return s->commandId;
 }
 
-CommandId
-GetScanCommandId(void)
-{
-	TransactionState s = CurrentTransactionState;
-
-	return s->scanCommandId;
-}
-
 
 /* --------------------------------
  *		GetCurrentTransactionStartTime
@@ -418,17 +410,6 @@ CommandIdIsCurrentCommandId(CommandId cid)
 	return (cid == s->commandId) ? true : false;
 }
 
-bool
-CommandIdGEScanCommandId(CommandId cid)
-{
-	TransactionState s = CurrentTransactionState;
-
-	if (AMI_OVERRIDE)
-		return false;
-
-	return (cid >= s->scanCommandId) ? true : false;
-}
-
 
 /* --------------------------------
  *		CommandCounterIncrement
@@ -437,11 +418,17 @@ CommandIdGEScanCommandId(CommandId cid)
 void
 CommandCounterIncrement(void)
 {
-	CurrentTransactionStateData.commandId += 1;
-	if (CurrentTransactionStateData.commandId == FirstCommandId)
+	TransactionState s = CurrentTransactionState;
+
+	s->commandId += 1;
+	if (s->commandId == FirstCommandId)	/* check for overflow */
 		elog(ERROR, "You may only have 2^32-1 commands per transaction");
 
-	CurrentTransactionStateData.scanCommandId = CurrentTransactionStateData.commandId;
+	/* Propagate new command ID into query snapshots, if set */
+	if (QuerySnapshot)
+		QuerySnapshot->curcid = s->commandId;
+	if (SerializableSnapshot)
+		SerializableSnapshot->curcid = s->commandId;
 
 	/*
 	 * make cache changes visible to me.  AtCommit_LocalCache() instead of
@@ -451,11 +438,6 @@ CommandCounterIncrement(void)
 	AtStart_Cache();
 }
 
-void
-SetScanCommandId(CommandId savedId)
-{
-	CurrentTransactionStateData.scanCommandId = savedId;
-}
 
 /* ----------------------------------------------------------------
  *						StartTransaction stuff
@@ -889,10 +871,6 @@ StartTransaction(void)
 	 * initialize current transaction state fields
 	 */
 	s->commandId = FirstCommandId;
-	s->scanCommandId = FirstCommandId;
-#if NOT_USED
-	s->startTime = GetCurrentAbsoluteTime();
-#endif
 	s->startTime = GetCurrentAbsoluteTimeUsec(&(s->startTimeUsec));
 
 	/*
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5f734ff544..3d1784870e 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.130 2002/05/20 23:51:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.131 2002/05/21 22:05:53 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -680,7 +680,7 @@ InsertOneTuple(Oid objectid)
 
 	if (objectid != (Oid) 0)
 		tuple->t_data->t_oid = objectid;
-	heap_insert(boot_reldesc, tuple);
+	simple_heap_insert(boot_reldesc, tuple);
 	heap_freetuple(tuple);
 	elog(DEBUG3, "row inserted");
 
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 1769733633..c206196bfc 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.200 2002/05/20 23:51:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.201 2002/05/21 22:05:53 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -440,7 +440,7 @@ AddNewAttributeTuples(Oid new_rel_oid,
 							 ATTRIBUTE_TUPLE_SIZE,
 							 (void *) *dpp);
 
-		heap_insert(rel, tup);
+		simple_heap_insert(rel, tup);
 
 		if (hasindex)
 			CatalogIndexInsert(idescs, Num_pg_attr_indices, rel, tup);
@@ -474,7 +474,7 @@ AddNewAttributeTuples(Oid new_rel_oid,
 			/* attStruct->attstattarget = 0; */
 			/* attStruct->attcacheoff = -1; */
 
-			heap_insert(rel, tup);
+			simple_heap_insert(rel, tup);
 
 			if (hasindex)
 				CatalogIndexInsert(idescs, Num_pg_attr_indices, rel, tup);
@@ -574,7 +574,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 	/*
 	 * finally insert the new tuple and free it.
 	 */
-	heap_insert(pg_class_desc, tup);
+	simple_heap_insert(pg_class_desc, tup);
 
 	if (!IsIgnoringSystemIndexes())
 	{
@@ -1308,7 +1308,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
 												 CStringGetDatum(adsrc));
 	adrel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
 	tuple = heap_formtuple(adrel->rd_att, values, nulls);
-	heap_insert(adrel, tuple);
+	simple_heap_insert(adrel, tuple);
 	CatalogOpenIndices(Num_pg_attrdef_indices, Name_pg_attrdef_indices,
 					   idescs);
 	CatalogIndexInsert(idescs, Num_pg_attrdef_indices, adrel, tuple);
@@ -1388,7 +1388,7 @@ StoreRelCheck(Relation rel, char *ccname, char *ccbin)
 												 CStringGetDatum(ccsrc));
 	rcrel = heap_openr(RelCheckRelationName, RowExclusiveLock);
 	tuple = heap_formtuple(rcrel->rd_att, values, nulls);
-	heap_insert(rcrel, tuple);
+	simple_heap_insert(rcrel, tuple);
 	CatalogOpenIndices(Num_pg_relcheck_indices, Name_pg_relcheck_indices,
 					   idescs);
 	CatalogIndexInsert(idescs, Num_pg_relcheck_indices, rcrel, tuple);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 84cc2fe9b1..a0f7f9b4cd 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.178 2002/05/20 23:51:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.179 2002/05/21 22:05:53 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -327,7 +327,7 @@ UpdateRelationRelation(Relation indexRelation)
 	 * sure would be embarrassing to do this sort of thing in polite company.
 	 */
 	tuple->t_data->t_oid = RelationGetRelid(indexRelation);
-	heap_insert(pg_class, tuple);
+	simple_heap_insert(pg_class, tuple);
 
 	/*
 	 * During normal processing, we need to make sure that the system
@@ -408,7 +408,7 @@ AppendAttributeTuples(Relation indexRelation, int numatts)
 								   ATTRIBUTE_TUPLE_SIZE,
 								   (void *) indexTupDesc->attrs[i]);
 
-		heap_insert(pg_attribute, new_tuple);
+		simple_heap_insert(pg_attribute, new_tuple);
 
 		if (hasind)
 			CatalogIndexInsert(idescs, Num_pg_attr_indices, pg_attribute, new_tuple);
@@ -500,7 +500,7 @@ UpdateIndexRelation(Oid indexoid,
 	/*
 	 * insert the tuple into the pg_index
 	 */
-	heap_insert(pg_index, tuple);
+	simple_heap_insert(pg_index, tuple);
 
 	/*
 	 * add index tuples for it
@@ -1010,7 +1010,8 @@ LockClassinfoForUpdate(Oid relid, HeapTuple rtup,
 		ItemPointerData tidsave;
 
 		ItemPointerCopy(&(rtup->t_self), &tidsave);
-		test = heap_mark4update(relationRelation, rtup, buffer);
+		test = heap_mark4update(relationRelation, rtup, buffer,
+								GetCurrentCommandId());
 		switch (test)
 		{
 			case HeapTupleSelfUpdated:
diff --git a/src/backend/catalog/pg_aggregate.c b/src/backend/catalog/pg_aggregate.c
index 3e586f0b52..1853acda73 100644
--- a/src/backend/catalog/pg_aggregate.c
+++ b/src/backend/catalog/pg_aggregate.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.46 2002/05/18 13:47:59 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.47 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -174,7 +174,7 @@ AggregateCreate(const char *aggName,
 	tupDesc = aggdesc->rd_att;
 
 	tup = heap_formtuple(tupDesc, values, nulls);
-	heap_insert(aggdesc, tup);
+	simple_heap_insert(aggdesc, tup);
 
 	if (RelationGetForm(aggdesc)->relhasindex)
 	{
diff --git a/src/backend/catalog/pg_largeobject.c b/src/backend/catalog/pg_largeobject.c
index d4b5e6bfeb..bc3c69f6e7 100644
--- a/src/backend/catalog/pg_largeobject.c
+++ b/src/backend/catalog/pg_largeobject.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_largeobject.c,v 1.11 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_largeobject.c,v 1.12 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,7 +63,7 @@ LargeObjectCreate(Oid loid)
 	/*
 	 * Insert it
 	 */
-	heap_insert(pg_largeobject, ntup);
+	simple_heap_insert(pg_largeobject, ntup);
 
 	/*
 	 * Update indices
diff --git a/src/backend/catalog/pg_namespace.c b/src/backend/catalog/pg_namespace.c
index e2cf0128dc..f95dafd8ee 100644
--- a/src/backend/catalog/pg_namespace.c
+++ b/src/backend/catalog/pg_namespace.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_namespace.c,v 1.2 2002/03/31 06:26:30 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_namespace.c,v 1.3 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -61,13 +61,10 @@ NamespaceCreate(const char *nspName, int32 ownerSysId)
 
 	nspdesc = heap_openr(NamespaceRelationName, RowExclusiveLock);
 	tupDesc = nspdesc->rd_att;
-	if (!HeapTupleIsValid(tup = heap_formtuple(tupDesc,
-											   values,
-											   nulls)))
-		elog(ERROR, "NamespaceCreate: heap_formtuple failed");
-	nspoid = heap_insert(nspdesc, tup);
-	if (!OidIsValid(nspoid))
-		elog(ERROR, "NamespaceCreate: heap_insert failed");
+
+	tup = heap_formtuple(tupDesc, values, nulls);
+	nspoid = simple_heap_insert(nspdesc, tup);
+	Assert(OidIsValid(nspoid));
 
 	if (RelationGetForm(nspdesc)->relhasindex)
 	{
diff --git a/src/backend/catalog/pg_operator.c b/src/backend/catalog/pg_operator.c
index 53a5d61cd9..874626ac91 100644
--- a/src/backend/catalog/pg_operator.c
+++ b/src/backend/catalog/pg_operator.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_operator.c,v 1.68 2002/04/27 03:45:00 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_operator.c,v 1.69 2002/05/21 22:05:54 tgl Exp $
  *
  * NOTES
  *	  these routines moved here from commands/define.c and somewhat cleaned up.
@@ -260,8 +260,7 @@ OperatorShellMake(const char *operatorName,
 	/*
 	 * insert our "shell" operator tuple
 	 */
-	heap_insert(pg_operator_desc, tup);
-	operatorObjectId = tup->t_data->t_oid;
+	operatorObjectId = simple_heap_insert(pg_operator_desc, tup);
 
 	if (RelationGetForm(pg_operator_desc)->relhasindex)
 	{
@@ -360,7 +359,7 @@ OperatorShellMake(const char *operatorName,
  *	 get the t_self from the modified tuple and call RelationReplaceHeapTuple
  * else if a new operator is being created
  *	 create a tuple using heap_formtuple
- *	 call heap_insert
+ *	 call simple_heap_insert
  */
 void
 OperatorCreate(const char *operatorName,
@@ -647,8 +646,7 @@ OperatorCreate(const char *operatorName,
 		tupDesc = pg_operator_desc->rd_att;
 		tup = heap_formtuple(tupDesc, values, nulls);
 
-		heap_insert(pg_operator_desc, tup);
-		operatorObjectId = tup->t_data->t_oid;
+		operatorObjectId = simple_heap_insert(pg_operator_desc, tup);
 	}
 
 	/* Must update the indexes in either case */
diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index 6fa6a4bf6f..4d656d98ba 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.72 2002/05/18 13:47:59 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.73 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -298,7 +298,7 @@ ProcedureCreate(const char *procedureName,
 		nulls[Anum_pg_proc_proacl-1] = 'n';
 
 		tup = heap_formtuple(tupDesc, values, nulls);
-		heap_insert(rel, tup);
+		simple_heap_insert(rel, tup);
 	}
 
 	/* Need to update indices for either the insert or update case */
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index 15c24c077a..d07e8c2439 100644
--- a/src/backend/catalog/pg_type.c
+++ b/src/backend/catalog/pg_type.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.70 2002/03/29 19:06:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.71 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -102,8 +102,7 @@ TypeShellMake(const char *typeName, Oid typeNamespace)
 	/*
 	 * insert the tuple in the relation and get the tuple's oid.
 	 */
-	heap_insert(pg_type_desc, tup);
-	typoid = tup->t_data->t_oid;
+	typoid = simple_heap_insert(pg_type_desc, tup);
 
 	if (RelationGetForm(pg_type_desc)->relhasindex)
 	{
@@ -286,9 +285,7 @@ TypeCreate(const char *typeName,
 		/* preassign tuple Oid, if one was given */
 		tup->t_data->t_oid = assignedTypeOid;
 
-		heap_insert(pg_type_desc, tup);
-
-		typeObjectId = tup->t_data->t_oid;
+		typeObjectId = simple_heap_insert(pg_type_desc, tup);
 	}
 
 	/* Update indices (not necessary if bootstrapping) */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c015043843..3f5cc96f41 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.33 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.34 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1787,7 +1787,7 @@ update_attstats(Oid relid, int natts, VacAttrStats **vacattrstats)
 		{
 			/* No, insert new tuple */
 			stup = heap_formtuple(sd->rd_att, values, nulls);
-			heap_insert(sd, stup);
+			simple_heap_insert(sd, stup);
 		}
 
 		/* update indices too */
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 271be15119..7ed3663a48 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.85 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.86 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -242,7 +242,7 @@ Async_Listen(char *relname, int pid)
 	values[i++] = (Datum) 0;	/* no notifies pending */
 
 	tuple = heap_formtuple(RelationGetDescr(lRel), values, nulls);
-	heap_insert(lRel, tuple);
+	simple_heap_insert(lRel, tuple);
 
 #ifdef NOT_USED					/* currently there are no indexes */
 	if (RelationGetForm(lRel)->relhasindex)
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a6215cb23f..be60227402 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.80 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.81 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -241,7 +241,7 @@ rebuildheap(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
 		 */
 		HeapTuple	copiedTuple = heap_copytuple(LocalHeapTuple);
 
-		heap_insert(LocalNewHeap, copiedTuple);
+		simple_heap_insert(LocalNewHeap, copiedTuple);
 		heap_freetuple(copiedTuple);
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/commands/comment.c b/src/backend/commands/comment.c
index 9d48e33b2c..7286720614 100644
--- a/src/backend/commands/comment.c
+++ b/src/backend/commands/comment.c
@@ -7,7 +7,7 @@
  * Copyright (c) 1999-2001, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/comment.c,v 1.47 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/comment.c,v 1.48 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -199,7 +199,7 @@ CreateComments(Oid oid, Oid classoid, int32 subid, char *comment)
 	{
 		newtuple = heap_formtuple(RelationGetDescr(description),
 								  values, nulls);
-		heap_insert(description, newtuple);
+		simple_heap_insert(description, newtuple);
 	}
 
 	/* Update indexes, if necessary */
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 1f9aef8fc0..83ca5b32c5 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.154 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.155 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -947,7 +947,7 @@ CopyFrom(Relation rel, bool binary, bool oids, FILE *fp,
 			/*
 			 * OK, store the tuple and create index entries for it
 			 */
-			heap_insert(rel, tuple);
+			simple_heap_insert(rel, tuple);
 
 			if (resultRelInfo->ri_NumIndices > 0)
 				ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index d4bc274ba2..bdba0dacfc 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.90 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.91 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -293,7 +293,7 @@ createdb(const char *dbname, const char *dbowner,
 	tuple->t_data->t_oid = dboid;		/* override heap_insert's OID
 										 * selection */
 
-	heap_insert(pg_database_rel, tuple);
+	simple_heap_insert(pg_database_rel, tuple);
 
 	/*
 	 * Update indexes
diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c
index 6f690c0927..754ea46246 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.1 2002/04/15 05:22:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.2 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -74,7 +74,6 @@ PerformPortalFetch(char *name,
 	EState	   *estate;
 	MemoryContext oldcontext;
 	ScanDirection direction;
-	CommandId	savedId;
 	bool		temp_desc = false;
 
 	/* initialize completion status in case of early exit */
@@ -131,14 +130,6 @@ PerformPortalFetch(char *name,
 		temp_desc = true;
 	}
 
-	/*
-	 * Restore the scanCommandId that was current when the cursor was
-	 * opened.  This ensures that we see the same tuples throughout the
-	 * execution of the cursor.
-	 */
-	savedId = GetScanCommandId();
-	SetScanCommandId(PortalGetCommandId(portal));
-
 	/*
 	 * Determine which direction to go in, and check to see if we're
 	 * already at the end of the available tuples in that direction.  If
@@ -185,11 +176,6 @@ PerformPortalFetch(char *name,
 				 (dest == None) ? "MOVE" : "FETCH",
 				 estate->es_processed);
 
-	/*
-	 * Restore outer command ID.
-	 */
-	SetScanCommandId(savedId);
-
 	/*
 	 * Clean up and switch back to old context.
 	 */
diff --git a/src/backend/commands/proclang.c b/src/backend/commands/proclang.c
index 2ad25fdbd4..6cabbf0ec1 100644
--- a/src/backend/commands/proclang.c
+++ b/src/backend/commands/proclang.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/proclang.c,v 1.31 2002/04/15 05:22:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/proclang.c,v 1.32 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -102,7 +102,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	tupDesc = rel->rd_att;
 	tup = heap_formtuple(tupDesc, values, nulls);
 
-	heap_insert(rel, tup);
+	simple_heap_insert(rel, tup);
 
 	if (RelationGetForm(rel)->relhasindex)
 	{
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 0fa56fcfb7..c79e6f97e1 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.77 2002/04/15 05:22:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.78 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -197,7 +197,7 @@ DefineSequence(CreateSeqStmt *seq)
 
 	/* Now form & insert sequence tuple */
 	tuple = heap_formtuple(tupDesc, value, null);
-	heap_insert(rel, tuple);
+	simple_heap_insert(rel, tuple);
 
 	Assert(ItemPointerGetOffsetNumber(&(tuple->t_self)) == FirstOffsetNumber);
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index f2bbdb0107..aff1590f11 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.15 2002/05/20 23:51:42 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.16 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -821,7 +821,7 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 
 		tuple = heap_formtuple(desc, datum, nullarr);
 
-		heap_insert(relation, tuple);
+		simple_heap_insert(relation, tuple);
 
 		if (RelationGetForm(relation)->relhasindex)
 		{
@@ -1673,7 +1673,7 @@ AlterTableAddColumn(Oid myrelid,
 
 	ReleaseSysCache(typeTuple);
 
-	heap_insert(attrdesc, attributeTuple);
+	simple_heap_insert(attrdesc, attributeTuple);
 
 	/* Update indexes on pg_attribute */
 	if (RelationGetForm(attrdesc)->relhasindex)
@@ -2890,7 +2890,8 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
 	classtuple.t_self = reltup->t_self;
 	ReleaseSysCache(reltup);
 
-	switch (heap_mark4update(class_rel, &classtuple, &buffer))
+	switch (heap_mark4update(class_rel, &classtuple, &buffer,
+							 GetCurrentCommandId()))
 	{
 		case HeapTupleSelfUpdated:
 		case HeapTupleMayBeUpdated:
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index a871c85788..e0b01b6fee 100644
--- a/src/backend/commands/trigger.c
+++ b/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 1.117 2002/04/30 01:24:57 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.118 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -270,7 +270,7 @@ CreateTrigger(CreateTrigStmt *stmt)
 	/*
 	 * Insert tuple into pg_trigger.
 	 */
-	heap_insert(tgrel, tuple);
+	simple_heap_insert(tgrel, tuple);
 	CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
 	CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
 	CatalogCloseIndices(Num_pg_trigger_indices, idescs);
@@ -1183,7 +1183,8 @@ GetTupleForTrigger(EState *estate, ResultRelInfo *relinfo,
 		*newSlot = NULL;
 		tuple.t_self = *tid;
 ltrmark:;
-		test = heap_mark4update(relation, &tuple, &buffer);
+		test = heap_mark4update(relation, &tuple, &buffer,
+								GetCurrentCommandId());
 		switch (test)
 		{
 			case HeapTupleSelfUpdated:
diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index c7c3da9dd4..98f47dd98b 100644
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.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/commands/user.c,v 1.102 2002/05/20 23:51:42 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/user.c,v 1.103 2002/05/21 22:05:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -596,7 +596,7 @@ CreateUser(CreateUserStmt *stmt)
 	/*
 	 * Insert new record in the pg_shadow table
 	 */
-	heap_insert(pg_shadow_rel, tuple);
+	simple_heap_insert(pg_shadow_rel, tuple);
 
 	/*
 	 * Update indexes
@@ -1213,9 +1213,9 @@ CreateGroup(CreateGroupStmt *stmt)
 	tuple = heap_formtuple(pg_group_dsc, new_record, new_record_nulls);
 
 	/*
-	 * Insert a new record in the pg_group_table
+	 * Insert a new record in the pg_group table
 	 */
-	heap_insert(pg_group_rel, tuple);
+	simple_heap_insert(pg_group_rel, tuple);
 
 	/*
 	 * Update indexes
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index a2c43bc035..a8c776bab2 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -27,7 +27,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.161 2002/05/12 20:10:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.162 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -101,6 +101,7 @@ TupleDesc
 ExecutorStart(QueryDesc *queryDesc, EState *estate)
 {
 	TupleDesc	result;
+	Snapshot	es_snapshot;
 
 	/* sanity checks */
 	Assert(queryDesc != NULL);
@@ -114,22 +115,28 @@ ExecutorStart(QueryDesc *queryDesc, EState *estate)
 	}
 
 	/*
-	 * Make our own private copy of the current queries snapshot data
+	 * Make our own private copy of the current query snapshot data.
+	 *
+	 * This "freezes" our idea of which tuples are good and which are not
+	 * for the life of this query, even if it outlives the current command
+	 * and current snapshot.
 	 */
-	if (QuerySnapshot == NULL)
-		estate->es_snapshot = NULL;
-	else
+	if (QuerySnapshot == NULL)	/* should be set already, but... */
+		SetQuerySnapshot();
+
+	es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
+	memcpy(es_snapshot, QuerySnapshot, sizeof(SnapshotData));
+	if (es_snapshot->xcnt > 0)
 	{
-		estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
-		memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
-		if (estate->es_snapshot->xcnt > 0)
-		{
-			estate->es_snapshot->xip = (TransactionId *)
-				palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
-			memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
-				   estate->es_snapshot->xcnt * sizeof(TransactionId));
-		}
+		es_snapshot->xip = (TransactionId *)
+			palloc(es_snapshot->xcnt * sizeof(TransactionId));
+		memcpy(es_snapshot->xip, QuerySnapshot->xip,
+			   es_snapshot->xcnt * sizeof(TransactionId));
 	}
+	else
+		es_snapshot->xip = NULL;
+
+	estate->es_snapshot = es_snapshot;
 
 	/*
 	 * Initialize the plan
@@ -1031,7 +1038,8 @@ lnext:	;
 							 erm->resname);
 
 					tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
-					test = heap_mark4update(erm->relation, &tuple, &buffer);
+					test = heap_mark4update(erm->relation, &tuple, &buffer,
+											estate->es_snapshot->curcid);
 					ReleaseBuffer(buffer);
 					switch (test)
 					{
@@ -1163,7 +1171,8 @@ ExecRetrieve(TupleTableSlot *slot,
 	 */
 	if (estate->es_into_relation_descriptor != NULL)
 	{
-		heap_insert(estate->es_into_relation_descriptor, tuple);
+		heap_insert(estate->es_into_relation_descriptor, tuple,
+					estate->es_snapshot->curcid);
 		IncrAppended();
 	}
 
@@ -1239,7 +1248,8 @@ ExecAppend(TupleTableSlot *slot,
 	/*
 	 * insert the tuple
 	 */
-	newId = heap_insert(resultRelationDesc, tuple);
+	newId = heap_insert(resultRelationDesc, tuple,
+						estate->es_snapshot->curcid);
 
 	IncrAppended();
 	(estate->es_processed)++;
@@ -1301,7 +1311,9 @@ ExecDelete(TupleTableSlot *slot,
 	 * delete the tuple
 	 */
 ldelete:;
-	result = heap_delete(resultRelationDesc, tupleid, &ctid);
+	result = heap_delete(resultRelationDesc, tupleid,
+						 &ctid,
+						 estate->es_snapshot->curcid);
 	switch (result)
 	{
 		case HeapTupleSelfUpdated:
@@ -1433,7 +1445,9 @@ lreplace:;
 	/*
 	 * replace the heap tuple
 	 */
-	result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
+	result = heap_update(resultRelationDesc, tupleid, tuple,
+						 &ctid,
+						 estate->es_snapshot->curcid);
 	switch (result)
 	{
 		case HeapTupleSelfUpdated:
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index 938f7e17f9..1265bc78d4 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.50 2002/05/12 20:10:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.51 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -465,7 +465,6 @@ fmgr_sql(PG_FUNCTION_ARGS)
 	SQLFunctionCachePtr fcache;
 	execution_state *es;
 	Datum		result = 0;
-	CommandId	savedId;
 
 	/*
 	 * Switch to context in which the fcache lives.  This ensures that
@@ -474,14 +473,6 @@ fmgr_sql(PG_FUNCTION_ARGS)
 	 */
 	oldcontext = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
 
-	/*
-	 * Before we start do anything we must save CurrentScanCommandId to
-	 * restore it before return to upper Executor. Also, we have to set
-	 * CurrentScanCommandId equal to CurrentCommandId. - vadim 08/29/97
-	 */
-	savedId = GetScanCommandId();
-	SetScanCommandId(GetCurrentCommandId());
-
 	/*
 	 * Initialize fcache and execution state if first time through.
 	 */
@@ -515,11 +506,6 @@ fmgr_sql(PG_FUNCTION_ARGS)
 		es = es->next;
 	}
 
-	/*
-	 * Restore outer command ID.
-	 */
-	SetScanCommandId(savedId);
-
 	/*
 	 * If we've gone through every command in this function, we are done.
 	 */
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index b9bcce30e2..9c445650e5 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.69 2002/04/15 05:22:04 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.70 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -106,11 +106,7 @@ SPI_connect(void)
 	/* ... and switch to procedure's context */
 	_SPI_current->savedcxt = MemoryContextSwitchTo(_SPI_current->procCxt);
 
-	_SPI_current->savedId = GetScanCommandId();
-	SetScanCommandId(GetCurrentCommandId());
-
 	return SPI_OK_CONNECT;
-
 }
 
 int
@@ -129,8 +125,6 @@ SPI_finish(void)
 	MemoryContextDelete(_SPI_current->execCxt);
 	MemoryContextDelete(_SPI_current->procCxt);
 
-	SetScanCommandId(_SPI_current->savedId);
-
 	/*
 	 * After _SPI_begin_call _SPI_connected == _SPI_curid. Now we are
 	 * closing connection to SPI and returning to upper Executor and so
@@ -1233,7 +1227,6 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
 	EState	   *estate;
 	MemoryContext oldcontext;
 	ScanDirection direction;
-	CommandId	savedId;
 	CommandDest olddest;
 
 	/* Check that the portal is valid */
@@ -1260,14 +1253,6 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
 	olddest = querydesc->dest;
 	querydesc->dest = dest;
 
-	/*
-	 * Restore the scanCommandId that was current when the cursor was
-	 * opened.  This ensures that we see the same tuples throughout the
-	 * execution of the cursor.
-	 */
-	savedId = GetScanCommandId();
-	SetScanCommandId(PortalGetCommandId(portal));
-
 	/* Run the executor like PerformPortalFetch and remember states */
 	if (forward)
 	{
@@ -1300,11 +1285,6 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
 
 	_SPI_current->processed = estate->es_processed;
 
-	/*
-	 * Restore outer command ID.
-	 */
-	SetScanCommandId(savedId);
-
 	/* Restore the old command destination and switch back to callers */
 	/* memory context */
 	querydesc->dest = olddest;
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index 4b1799ff2e..81fd39df36 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.71 2002/05/20 23:51:43 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.72 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -88,9 +88,7 @@ InsertRule(char *rulname,
 						 values,
 						 nulls);
 
-	heap_insert(pg_rewrite_desc, tup);
-
-	rewriteObjectId = tup->t_data->t_oid;
+	rewriteObjectId = simple_heap_insert(pg_rewrite_desc, tup);
 
 	if (RelationGetForm(pg_rewrite_desc)->relhasindex)
 	{
diff --git a/src/backend/storage/ipc/sinval.c b/src/backend/storage/ipc/sinval.c
index 865c96ed8f..a32c8ae703 100644
--- a/src/backend/storage/ipc/sinval.c
+++ b/src/backend/storage/ipc/sinval.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.45 2002/03/02 23:35:57 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.46 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -397,6 +397,9 @@ GetSnapshotData(bool serializable)
 	Assert(TransactionIdIsValid(MyProc->xmin));
 
 	snapshot->xcnt = count;
+
+	snapshot->curcid = GetCurrentCommandId();
+
 	return snapshot;
 }
 
diff --git a/src/backend/storage/large_object/inv_api.c b/src/backend/storage/large_object/inv_api.c
index a470a870df..fb0bf88809 100644
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.91 2002/05/20 23:51:43 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.92 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -555,7 +555,7 @@ inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes)
 			values[Anum_pg_largeobject_pageno - 1] = Int32GetDatum(pageno);
 			values[Anum_pg_largeobject_data - 1] = PointerGetDatum(&workbuf);
 			newtup = heap_formtuple(obj_desc->heap_r->rd_att, values, nulls);
-			heap_insert(obj_desc->heap_r, newtup);
+			simple_heap_insert(obj_desc->heap_r, newtup);
 			if (write_indices)
 				CatalogIndexInsert(idescs, Num_pg_largeobject_indices,
 								   obj_desc->heap_r, newtup);
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
index 318827ed95..90e9ca6a71 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/mmgr/portalmem.c,v 1.47 2002/03/06 06:10:29 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/mmgr/portalmem.c,v 1.48 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -168,7 +168,6 @@ PortalSetQuery(Portal portal,
 
 	portal->queryDesc = queryDesc;
 	portal->attinfo = attinfo;
-	portal->commandId = GetScanCommandId();
 	portal->state = state;
 	portal->atStart = true;		/* Allow fetch forward only */
 	portal->atEnd = false;
@@ -214,7 +213,6 @@ CreatePortal(char *name)
 	/* initialize portal query */
 	portal->queryDesc = NULL;
 	portal->attinfo = NULL;
-	portal->commandId = 0;
 	portal->state = NULL;
 	portal->atStart = true;		/* disallow fetches until query is set */
 	portal->atEnd = true;
diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c
index ba052e5f77..58534159f7 100644
--- a/src/backend/utils/time/tqual.c
+++ b/src/backend/utils/time/tqual.c
@@ -16,7 +16,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.50 2002/05/06 02:39:01 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.51 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -238,7 +238,7 @@ HeapTupleSatisfiesNow(HeapTupleHeader tuple)
 		}
 		else if (TransactionIdIsCurrentTransactionId(tuple->t_xmin))
 		{
-			if (CommandIdGEScanCommandId(tuple->t_cmin))
+			if (tuple->t_cmin >= GetCurrentCommandId())
 				return false;	/* inserted after scan started */
 
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
@@ -249,7 +249,7 @@ HeapTupleSatisfiesNow(HeapTupleHeader tuple)
 			if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
 				return true;
 
-			if (CommandIdGEScanCommandId(tuple->t_cmax))
+			if (tuple->t_cmax >= GetCurrentCommandId())
 				return true;	/* deleted after scan started */
 			else
 				return false;	/* deleted before scan started */
@@ -280,7 +280,7 @@ HeapTupleSatisfiesNow(HeapTupleHeader tuple)
 	{
 		if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
 			return true;
-		if (CommandIdGEScanCommandId(tuple->t_cmax))
+		if (tuple->t_cmax >= GetCurrentCommandId())
 			return true;		/* deleted after scan started */
 		else
 			return false;		/* deleted before scan started */
@@ -363,10 +363,12 @@ HeapTupleSatisfiesToast(HeapTupleHeader tuple)
  * HeapTupleSatisfiesUpdate
  *
  *	Same logic as HeapTupleSatisfiesNow, but returns a more detailed result
- *	code, since UPDATE needs to know more than "is it visible?".
+ *	code, since UPDATE needs to know more than "is it visible?".  Also,
+ *	tuples of my own xact are tested against the passed CommandId not
+ *	CurrentCommandId.
  */
 int
-HeapTupleSatisfiesUpdate(HeapTuple htuple)
+HeapTupleSatisfiesUpdate(HeapTuple htuple, CommandId curcid)
 {
 	HeapTupleHeader tuple = htuple->t_data;
 
@@ -409,7 +411,7 @@ HeapTupleSatisfiesUpdate(HeapTuple htuple)
 		}
 		else if (TransactionIdIsCurrentTransactionId(tuple->t_xmin))
 		{
-			if (CommandIdGEScanCommandId(tuple->t_cmin))
+			if (tuple->t_cmin >= curcid)
 				return HeapTupleInvisible;		/* inserted after scan
 												 * started */
 
@@ -421,7 +423,7 @@ HeapTupleSatisfiesUpdate(HeapTuple htuple)
 			if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
 				return HeapTupleMayBeUpdated;
 
-			if (CommandIdGEScanCommandId(tuple->t_cmax))
+			if (tuple->t_cmax >= curcid)
 				return HeapTupleSelfUpdated;	/* updated after scan
 												 * started */
 			else
@@ -454,7 +456,7 @@ HeapTupleSatisfiesUpdate(HeapTuple htuple)
 	{
 		if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
 			return HeapTupleMayBeUpdated;
-		if (CommandIdGEScanCommandId(tuple->t_cmax))
+		if (tuple->t_cmax >= curcid)
 			return HeapTupleSelfUpdated;		/* updated after scan
 												 * started */
 		else
@@ -677,7 +679,7 @@ HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 		}
 		else if (TransactionIdIsCurrentTransactionId(tuple->t_xmin))
 		{
-			if (CommandIdGEScanCommandId(tuple->t_cmin))
+			if (tuple->t_cmin >= snapshot->curcid)
 				return false;	/* inserted after scan started */
 
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
@@ -688,7 +690,7 @@ HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 			if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE)
 				return true;
 
-			if (CommandIdGEScanCommandId(tuple->t_cmax))
+			if (tuple->t_cmax >= snapshot->curcid)
 				return true;	/* deleted after scan started */
 			else
 				return false;	/* deleted before scan started */
@@ -730,7 +732,7 @@ HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 	{
 		if (TransactionIdIsCurrentTransactionId(tuple->t_xmax))
 		{
-			if (CommandIdGEScanCommandId(tuple->t_cmax))
+			if (tuple->t_cmax >= snapshot->curcid)
 				return true;	/* deleted after scan started */
 			else
 				return false;	/* deleted before scan started */
@@ -950,6 +952,7 @@ SetQuerySnapshot(void)
 	{
 		free(QuerySnapshot->xip);
 		free(QuerySnapshot);
+		QuerySnapshot = NULL;
 	}
 
 	if (XactIsoLevel == XACT_SERIALIZABLE)
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index b8f2394fc5..7bf75f512d 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.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: heapam.h,v 1.74 2002/05/20 23:51:43 tgl Exp $
+ * $Id: heapam.h,v 1.75 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -156,16 +156,23 @@ extern void heap_fetch(Relation relation, Snapshot snapshot,
 					   HeapTuple tuple, Buffer *userbuf,
 					   PgStat_Info *pgstat_info);
 
-extern ItemPointer heap_get_latest_tid(Relation relation, Snapshot snapshot, ItemPointer tid);
+extern ItemPointer heap_get_latest_tid(Relation relation, Snapshot snapshot,
+									   ItemPointer tid);
 extern void setLastTid(const ItemPointer tid);
-extern Oid	heap_insert(Relation relation, HeapTuple tup);
-extern int	heap_delete(Relation relation, ItemPointer tid, ItemPointer ctid);
+
+extern Oid	heap_insert(Relation relation, HeapTuple tup, CommandId cid);
+extern int	heap_delete(Relation relation, ItemPointer tid, ItemPointer ctid,
+						CommandId cid);
 extern int heap_update(Relation relation, ItemPointer otid, HeapTuple tup,
-			ItemPointer ctid);
-extern int	heap_mark4update(Relation relation, HeapTuple tup, Buffer *userbuf);
+					   ItemPointer ctid, CommandId cid);
+extern int	heap_mark4update(Relation relation, HeapTuple tup,
+							 Buffer *userbuf, CommandId cid);
+
+extern Oid	simple_heap_insert(Relation relation, HeapTuple tup);
 extern void simple_heap_delete(Relation relation, ItemPointer tid);
 extern void simple_heap_update(Relation relation, ItemPointer otid,
 				   HeapTuple tup);
+
 extern void heap_markpos(HeapScanDesc scan);
 extern void heap_restrpos(HeapScanDesc scan);
 
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index 0cfc1652f2..537d84b63d 100644
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.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: xact.h,v 1.42 2002/04/01 03:34:27 tgl Exp $
+ * $Id: xact.h,v 1.43 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,7 +38,6 @@ typedef struct TransactionStateData
 {
 	TransactionId transactionIdData;
 	CommandId	commandId;
-	CommandId	scanCommandId;
 	AbsoluteTime startTime;
 	int			startTimeUsec;
 	int			state;
@@ -101,13 +100,10 @@ extern bool IsTransactionState(void);
 extern bool IsAbortedTransactionBlockState(void);
 extern TransactionId GetCurrentTransactionId(void);
 extern CommandId GetCurrentCommandId(void);
-extern CommandId GetScanCommandId(void);
-extern void SetScanCommandId(CommandId);
 extern AbsoluteTime GetCurrentTransactionStartTime(void);
 extern AbsoluteTime GetCurrentTransactionStartTimeUsec(int *usec);
 extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
 extern bool CommandIdIsCurrentCommandId(CommandId cid);
-extern bool CommandIdGEScanCommandId(CommandId cid);
 extern void CommandCounterIncrement(void);
 extern void StartTransactionCommand(void);
 extern void CommitTransactionCommand(void);
diff --git a/src/include/executor/spi_priv.h b/src/include/executor/spi_priv.h
index dd8b187750..c780c3656f 100644
--- a/src/include/executor/spi_priv.h
+++ b/src/include/executor/spi_priv.h
@@ -3,7 +3,7 @@
  * spi.c
  *				Server Programming Interface private declarations
  *
- * $Header: /cvsroot/pgsql/src/include/executor/spi_priv.h,v 1.11 2001/11/05 17:46:33 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/include/executor/spi_priv.h,v 1.12 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,7 +20,6 @@ typedef struct
 	MemoryContext procCxt;		/* procedure context */
 	MemoryContext execCxt;		/* executor context */
 	MemoryContext savedcxt;
-	CommandId	savedId;
 } _SPI_connection;
 
 typedef struct
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index 9198b21feb..491106fac3 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.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: portal.h,v 1.32 2002/02/14 15:24:10 tgl Exp $
+ * $Id: portal.h,v 1.33 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,7 +31,6 @@ typedef struct PortalData
 	MemoryContext heap;			/* subsidiary memory */
 	QueryDesc  *queryDesc;		/* Info about query associated with portal */
 	TupleDesc	attinfo;
-	CommandId	commandId;		/* Command counter value for query */
 	EState	   *state;			/* Execution state of query */
 	bool		atStart;		/* T => fetch backwards is not allowed */
 	bool		atEnd;			/* T => fetch forwards is not allowed */
@@ -49,7 +48,6 @@ typedef struct PortalData
  */
 #define PortalGetQueryDesc(portal)	((portal)->queryDesc)
 #define PortalGetTupleDesc(portal)	((portal)->attinfo)
-#define PortalGetCommandId(portal)	((portal)->commandId)
 #define PortalGetState(portal)		((portal)->state)
 #define PortalGetHeapMemory(portal)	((portal)->heap)
 
diff --git a/src/include/utils/tqual.h b/src/include/utils/tqual.h
index a69851e666..f5f03ea01a 100644
--- a/src/include/utils/tqual.h
+++ b/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 1.38 2002/01/16 20:29:02 tgl Exp $
+ * $Id: tqual.h,v 1.39 2002/05/21 22:05:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -26,6 +26,7 @@ typedef struct SnapshotData
 	uint32		xcnt;			/* # of xact ids in xip[] */
 	TransactionId *xip;			/* array of xact IDs in progress */
 	/* note: all ids in xip[] satisfy xmin <= xip[i] < xmax */
+	CommandId	curcid;			/* in my xact, CID < curcid are visible */
 	ItemPointerData tid;		/* required for Dirty snapshot -:( */
 } SnapshotData;
 
@@ -104,7 +105,8 @@ extern bool HeapTupleSatisfiesDirty(HeapTupleHeader tuple);
 extern bool HeapTupleSatisfiesToast(HeapTupleHeader tuple);
 extern bool HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple,
 						   Snapshot snapshot);
-extern int	HeapTupleSatisfiesUpdate(HeapTuple tuple);
+extern int	HeapTupleSatisfiesUpdate(HeapTuple tuple,
+									 CommandId curcid);
 extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTupleHeader tuple,
 						 TransactionId OldestXmin);