Use Snapshot in heap access methods.

28 years ago · be8300b18f
parent f7f989c990
commit be8300b18f
54 changed files with 352 additions and 339 deletions
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@ -170,7 +170,7 @@ gistbuild(Relation heap,
 		econtext = NULL;
 	}
 #endif							/* OMIT_PARTIAL_INDEX */
-	scan = heap_beginscan(heap, 0, false, 0, (ScanKey) NULL);
+	scan = heap_beginscan(heap, 0, SnapshotNow, 0, (ScanKey) NULL);
 	htup = heap_getnext(scan, 0, &buffer);

 	/* int the tuples as we insert them */
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/hash/hash.c,v 1.18 1998/02/26 04:29:28 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/hash/hash.c,v 1.19 1998/07/27 19:37:35 vadim Exp $
 *
 * NOTES
 *	  This file contains only the public interface routines.
@ -121,7 +121,7 @@ hashbuild(Relation heap,
 #endif							/* OMIT_PARTIAL_INDEX */

 	/* start a heap scan */
-	hscan = heap_beginscan(heap, 0, false, 0, (ScanKey) NULL);
+	hscan = heap_beginscan(heap, 0, SnapshotNow, 0, (ScanKey) NULL);
 	htup = heap_getnext(hscan, 0, &buffer);

 	/* build the index */
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.30 1998/07/20 16:56:53 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.31 1998/07/27 19:37:36 vadim Exp $
 *
 *
 * INTERFACE ROUTINES
@ -209,7 +209,7 @@ heapgettup(Relation relation,
 		   ItemPointer tid,
 		   int dir,
 		   Buffer *b,
-		   bool seeself,
+		   Snapshot snapshot,
 		   int nkeys,
 		   ScanKey key)
 {
@ -250,9 +250,9 @@ heapgettup(Relation relation,
 	}
 	elog(DEBUG, "heapgettup(..., b=0x%x, nkeys=%d, key=0x%x", b, nkeys, key);

-	elog(DEBUG, "heapgettup: relation(%c)=`%s', %s",
+	elog(DEBUG, "heapgettup: relation(%c)=`%s', %p",
 		 relation->rd_rel->relkind, &relation->rd_rel->relname,
-		 (seeself == true) ? "SeeSelf" : "NoSeeSelf");
+		 snapshot);
 #endif							/* !defined(HEAPDEBUGALL) */

 	if (!ItemPointerIsValid(tid))
@ -402,7 +402,7 @@ heapgettup(Relation relation,
 			 * ----------------
 			 */
 			HeapTupleSatisfies(lpp, relation, *b, (PageHeader) dp,
-							   seeself, nkeys, key, rtup);
+							   snapshot, nkeys, key, rtup);
 			if (rtup != NULL)
 			{
 				ItemPointer iptr = &(rtup->t_ctid);
@ -580,7 +580,7 @@ heap_close(Relation relation)
 HeapScanDesc
 heap_beginscan(Relation relation,
 			   int atend,
-			   bool seeself,
+			   Snapshot snapshot,
 			   unsigned nkeys,
 			   ScanKey key)
 {
@ -608,7 +608,7 @@ heap_beginscan(Relation relation,

 	/* XXX someday assert SelfTimeQual if relkind == RELKIND_UNCATALOGED */
 	if (relation->rd_rel->relkind == RELKIND_UNCATALOGED)
-		seeself = true;
+		snapshot = SnapshotSelf;

 	/* ----------------
 	 *	increment relation ref count while scanning relation
@ -639,7 +639,7 @@ heap_beginscan(Relation relation,
 	initsdesc(sdesc, relation, atend, nkeys, key);

 	sdesc->rs_atend = atend;
-	sdesc->rs_seeself = seeself;
+	sdesc->rs_snapshot = snapshot;
 	sdesc->rs_nkeys = (short) nkeys;

 	return (sdesc);
@ -856,7 +856,7 @@ heap_getnext(HeapScanDesc scandesc,
 						   iptr,
 						   -1,
 						   &(sdesc->rs_cbuf),
-						   sdesc->rs_seeself,
+						   sdesc->rs_snapshot,
 						   sdesc->rs_nkeys,
 						   sdesc->rs_key);
 		}
@ -943,7 +943,7 @@ heap_getnext(HeapScanDesc scandesc,
 						   iptr,
 						   1,
 						   &sdesc->rs_cbuf,
-						   sdesc->rs_seeself,
+						   sdesc->rs_snapshot,
 						   sdesc->rs_nkeys,
 						   sdesc->rs_key);
 		}
@ -988,7 +988,7 @@ heap_getnext(HeapScanDesc scandesc,
 */
 HeapTuple
 heap_fetch(Relation relation,
-		   bool seeself,
+		   Snapshot snapshot,
 		   ItemPointer tid,
 		   Buffer *b)
 {
@ -1050,7 +1050,7 @@ heap_fetch(Relation relation,
 	 */

 	HeapTupleSatisfies(lp, relation, buffer, dp,
-					   seeself, 0, (ScanKey) NULL, tuple);
+					   snapshot, 0, (ScanKey) NULL, tuple);

 	if (tuple == NULL)
 	{
@ -1447,7 +1447,7 @@ heap_markpos(HeapScanDesc sdesc)
 					   (ItemPointer) NULL : &sdesc->rs_ctup->t_ctid,
 					   -1,
 					   &sdesc->rs_pbuf,
-					   sdesc->rs_seeself,
+					   sdesc->rs_snapshot,
 					   sdesc->rs_nkeys,
 					   sdesc->rs_key);

@ -1461,7 +1461,7 @@ heap_markpos(HeapScanDesc sdesc)
 					   (ItemPointer) NULL : &sdesc->rs_ctup->t_ctid,
 					   1,
 					   &sdesc->rs_nbuf,
-					   sdesc->rs_seeself,
+					   sdesc->rs_snapshot,
 					   sdesc->rs_nkeys,
 					   sdesc->rs_key);
 	}
--- a/src/backend/access/index/istrat.c
+++ b/src/backend/access/index/istrat.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/index/Attic/istrat.c,v 1.20 1998/06/15 19:27:54 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/index/Attic/istrat.c,v 1.21 1998/07/27 19:37:37 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -501,7 +501,7 @@ OperatorRelationFillScanKeyEntry(Relation operatorRelation,
 						   F_OIDEQ,
 						   ObjectIdGetDatum(operatorObjectId));

-	scan = heap_beginscan(operatorRelation, false, false,
+	scan = heap_beginscan(operatorRelation, false, SnapshotNow,
 						  1, &scanKeyData);

 	tuple = heap_getnext(scan, false, (Buffer *) NULL);
@ -558,7 +558,7 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 						   ObjectIdGetDatum(indexObjectId));

 	relation = heap_openr(IndexRelationName);
-	scan = heap_beginscan(relation, false, false, 1, entry);
+	scan = heap_beginscan(relation, false, SnapshotNow, 1, entry);
 	tuple = heap_getnext(scan, 0, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 		elog(ERROR, "IndexSupportInitialize: corrupted catalogs");
@ -618,7 +618,7 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 			entry[1].sk_argument =
 				ObjectIdGetDatum(operatorClassObjectId[attributeNumber - 1]);

-			scan = heap_beginscan(relation, false, false, 2, entry);
+			scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);

 			while (tuple = heap_getnext(scan, 0, (Buffer *) NULL),
 				   HeapTupleIsValid(tuple))
@ -661,7 +661,7 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 		for (strategy = 1; strategy <= maxStrategyNumber; strategy++)
 			ScanKeyEntrySetIllegal(StrategyMapGetScanKeyEntry(map, strategy));

-		scan = heap_beginscan(relation, false, false, 2, entry);
+		scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);

 		while (tuple = heap_getnext(scan, 0, (Buffer *) NULL),
 			   HeapTupleIsValid(tuple))
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.26 1998/06/15 19:27:55 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.27 1998/07/27 19:37:39 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -120,7 +120,7 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, Relation heapRel
 			{					/* they're equal */
 				btitem = (BTItem) PageGetItem(page, PageGetItemId(page, offset));
 				itup = &(btitem->bti_itup);
-				htup = heap_fetch(heapRel, true, &(itup->t_tid), NULL);
+				htup = heap_fetch(heapRel, SnapshotSelf, &(itup->t_tid), NULL);
 				if (htup != (HeapTuple) NULL)
 				{				/* it is a duplicate */
 					elog(ERROR, "Cannot insert a duplicate key into a unique index");
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.26 1998/06/15 19:27:56 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.27 1998/07/27 19:37:40 vadim Exp $
 *
 * NOTES
 *	  This file contains only the public interface routines.
@ -153,7 +153,7 @@ btbuild(Relation heap,
 #endif							/* OMIT_PARTIAL_INDEX */

 	/* start a heap scan */
-	hscan = heap_beginscan(heap, 0, false, 0, (ScanKey) NULL);
+	hscan = heap_beginscan(heap, 0, SnapshotNow, 0, (ScanKey) NULL);
 	htup = heap_getnext(hscan, 0, &buffer);

 	/* build the index */
--- a/src/backend/access/rtree/rtree.c
+++ b/src/backend/access/rtree/rtree.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/rtree/Attic/rtree.c,v 1.24 1998/06/15 19:28:01 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/rtree/Attic/rtree.c,v 1.25 1998/07/27 19:37:41 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -164,7 +164,7 @@ rtbuild(Relation heap,
 		slot = NULL;
 	}
 #endif							/* OMIT_PARTIAL_INDEX */
-	scan = heap_beginscan(heap, 0, false, 0, (ScanKey) NULL);
+	scan = heap_beginscan(heap, 0, SnapshotNow, 0, (ScanKey) NULL);
 	htup = heap_getnext(scan, 0, &buffer);

 	/* count the tuples as we insert them */
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@ -7,7 +7,7 @@
 * Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.46 1998/07/26 04:30:19 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.47 1998/07/27 19:37:43 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -41,13 +41,8 @@
 #include "catalog/catname.h"
 #include "catalog/index.h"
 #include "catalog/pg_am.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_attribute_mb.h"
-#include "catalog/pg_class_mb.h"
-#else
 #include "catalog/pg_attribute.h"
 #include "catalog/pg_class.h"
-#endif
 #include "catalog/pg_type.h"
 #include "executor/execdesc.h"
 #include "executor/hashjoin.h"
@ -464,14 +459,14 @@ boot_openrel(char *relname)
 	{
 		StartPortalAllocMode(DefaultAllocMode, 0);
 		rdesc = heap_openr(TypeRelationName);
-		sdesc = heap_beginscan(rdesc, 0, false, 0, (ScanKey) NULL);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 0, (ScanKey) NULL);
 		for (i = 0; PointerIsValid(tup = heap_getnext(sdesc, 0, (Buffer *) NULL)); ++i);
 		heap_endscan(sdesc);
 		app = Typ = ALLOC(struct typmap *, i + 1);
 		while (i-- > 0)
 			*app++ = ALLOC(struct typmap, 1);
 		*app = (struct typmap *) NULL;
-		sdesc = heap_beginscan(rdesc, 0, false, 0, (ScanKey) NULL);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 0, (ScanKey) NULL);
 		app = Typ;
 		while (PointerIsValid(tup = heap_getnext(sdesc, 0, (Buffer *) NULL)))
 		{
@ -817,7 +812,7 @@ gettype(char *type)
 		if (DebugMode)
 			printf("bootstrap.c: External Type: %s\n", type);
 		rdesc = heap_openr(TypeRelationName);
-		sdesc = heap_beginscan(rdesc, 0, false, 0, (ScanKey) NULL);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 0, (ScanKey) NULL);
 		i = 0;
 		while (PointerIsValid(tup = heap_getnext(sdesc, 0, (Buffer *) NULL)))
 			++i;
@ -826,7 +821,7 @@ gettype(char *type)
 		while (i-- > 0)
 			*app++ = ALLOC(struct typmap, 1);
 		*app = (struct typmap *) NULL;
-		sdesc = heap_beginscan(rdesc, 0, false, 0, (ScanKey) NULL);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 0, (ScanKey) NULL);
 		app = Typ;
 		while (PointerIsValid(tup = heap_getnext(sdesc, 0, (Buffer *) NULL)))
 		{
--- a/src/backend/catalog/aclchk.c
+++ b/src/backend/catalog/aclchk.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/aclchk.c,v 1.11 1998/06/15 19:28:06 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/aclchk.c,v 1.12 1998/07/27 19:37:45 vadim Exp $
 *
 * NOTES
 *	  See acl.h.
@ -126,7 +126,7 @@ ChangeAcl(char *relname,
 	relkey[0].sk_argument = NameGetDatum(relname);
 	hsdp = heap_beginscan(relation,
 						  0,
-						  false,
+						  SnapshotNow,
 						  (unsigned) 1,
 						  relkey);
 	htp = heap_getnext(hsdp, 0, &buffer);
@ -482,7 +482,7 @@ pg_aclcheck(char *relname, char *usename, AclMode mode)
 				  &relkey[0].sk_func,
 				  &relkey[0].sk_nargs);
 		relkey[0].sk_argument = NameGetDatum(relname);
-		hsdp = heap_beginscan(relation, 0, false, 1, relkey);
+		hsdp = heap_beginscan(relation, 0, SnapshotNow, 1, relkey);
 		htp = heap_getnext(hsdp, 0, (Buffer *) 0);
 		if (HeapTupleIsValid(htp) &&
 			!heap_attisnull(htp, Anum_pg_class_relacl))
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.54 1998/07/20 19:21:41 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.55 1998/07/27 19:37:46 vadim Exp $
 *
 * INTERFACE ROUTINES
 *		heap_create()			- Create an uncataloged heap relation
@ -502,7 +502,7 @@ RelationAlreadyExists(Relation pg_class_desc, char relname[])
 	 */
 	pg_class_scan = heap_beginscan(pg_class_desc,
 								   0,
-								   false,
+								   SnapshotNow,
 								   1,
 								   &key);

@ -896,7 +896,7 @@ RelationRemoveInheritance(Relation relation)

 	scan = heap_beginscan(catalogRelation,
 						  false,
-						  false,
+						  SnapshotNow,
 						  1,
 						  &entry);

@ -924,7 +924,7 @@ RelationRemoveInheritance(Relation relation)

 	scan = heap_beginscan(catalogRelation,
 						  false,
-						  false,
+						  SnapshotNow,
 						  1,
 						  &entry);

@ -950,7 +950,7 @@ RelationRemoveInheritance(Relation relation)

 	scan = heap_beginscan(catalogRelation,
 						  false,
-						  false,
+						  SnapshotNow,
 						  1,
 						  &entry);

@ -987,7 +987,7 @@ RelationRemoveIndexes(Relation relation)

 	scan = heap_beginscan(indexRelation,
 						  false,
-						  false,
+						  SnapshotNow,
 						  1,
 						  &entry);

@ -1033,7 +1033,7 @@ DeletePgRelationTuple(Relation rdesc)

 	pg_class_scan = heap_beginscan(pg_class_desc,
 								   0,
-								   false,
+								   SnapshotNow,
 								   1,
 								   &key);

@ -1097,7 +1097,7 @@ DeletePgAttributeTuples(Relation rdesc)

 	pg_attribute_scan = heap_beginscan(pg_attribute_desc,
 									   0,
-									   false,
+									   SnapshotNow,
 									   1,
 									   &key);

@ -1166,7 +1166,7 @@ DeletePgTypeTuple(Relation rdesc)

 	pg_type_scan = heap_beginscan(pg_type_desc,
 								  0,
-								  false,
+								  SnapshotNow,
 								  1,
 								  &key);

@ -1202,7 +1202,7 @@ DeletePgTypeTuple(Relation rdesc)

 	pg_attribute_scan = heap_beginscan(pg_attribute_desc,
 									   0,
-									   false,
+									   SnapshotNow,
 									   1,
 									   &attkey);

@ -1646,7 +1646,7 @@ RemoveAttrDefault(Relation rel)

 	RelationSetLockForWrite(adrel);

-	adscan = heap_beginscan(adrel, 0, false, 1, &key);
+	adscan = heap_beginscan(adrel, 0, SnapshotNow, 1, &key);

 	while (tup = heap_getnext(adscan, 0, (Buffer *) NULL), PointerIsValid(tup))
 		heap_delete(adrel, &tup->t_ctid);
@ -1673,7 +1673,7 @@ RemoveRelCheck(Relation rel)

 	RelationSetLockForWrite(rcrel);

-	rcscan = heap_beginscan(rcrel, 0, false, 1, &key);
+	rcscan = heap_beginscan(rcrel, 0, SnapshotNow, 1, &key);

 	while (tup = heap_getnext(rcscan, 0, (Buffer *) NULL), PointerIsValid(tup))
 		heap_delete(rcrel, &tup->t_ctid);
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.46 1998/07/20 19:21:42 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.47 1998/07/27 19:37:47 vadim Exp $
 *
 *
 * INTERFACE ROUTINES
@ -180,7 +180,7 @@ RelationNameGetObjectId(char *relationName,
 						   F_NAMEEQ,
 						   PointerGetDatum(relationName));

-	pg_class_scan = heap_beginscan(pg_class, 0, false, 1, &key);
+	pg_class_scan = heap_beginscan(pg_class, 0, SnapshotNow, 1, &key);

 	/* ----------------
 	 *	if we find the named relation, fetch its relation id
@ -506,7 +506,7 @@ AccessMethodObjectIdGetAccessMethodTupleForm(Oid accessMethodObjectId)
 	 * ----------------
 	 */
 	pg_am_desc = heap_openr(AccessMethodRelationName);
-	pg_am_scan = heap_beginscan(pg_am_desc, 0, false, 1, &key);
+	pg_am_scan = heap_beginscan(pg_am_desc, 0, SnapshotNow, 1, &key);

 	pg_am_tuple = heap_getnext(pg_am_scan, 0, (Buffer *) NULL);

@ -945,7 +945,7 @@ UpdateIndexPredicate(Oid indexoid, Node *oldPred, Node *predicate)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(indexoid));

-	scan = heap_beginscan(pg_index, 0, false, 1, &entry);
+	scan = heap_beginscan(pg_index, 0, SnapshotNow, 1, &entry);
 	tuple = heap_getnext(scan, 0, &buffer);
 	heap_endscan(scan);

@ -1238,7 +1238,7 @@ index_destroy(Oid indexId)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(indexId));;

-	scan = heap_beginscan(catalogRelation, 0, false, 1, &entry);
+	scan = heap_beginscan(catalogRelation, 0, SnapshotNow, 1, &entry);
 	tuple = heap_getnext(scan, 0, (Buffer *) NULL);

 	AssertState(HeapTupleIsValid(tuple));
@ -1255,7 +1255,7 @@ index_destroy(Oid indexId)

 	entry.sk_attno = Anum_pg_attribute_attrelid;

-	scan = heap_beginscan(catalogRelation, 0, false, 1, &entry);
+	scan = heap_beginscan(catalogRelation, 0, SnapshotNow, 1, &entry);

 	while (tuple = heap_getnext(scan, 0, (Buffer *) NULL),
 		   HeapTupleIsValid(tuple))
@ -1271,7 +1271,7 @@ index_destroy(Oid indexId)

 	entry.sk_attno = Anum_pg_index_indexrelid;

-	scan = heap_beginscan(catalogRelation, 0, false, 1, &entry);
+	scan = heap_beginscan(catalogRelation, 0, SnapshotNow, 1, &entry);
 	tuple = heap_getnext(scan, 0, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 	{
@ -1402,7 +1402,7 @@ UpdateStats(Oid relid, long reltuples, bool hasindex)
 	key[0].sk_argument = ObjectIdGetDatum(relid);

 	pg_class_scan =
-		heap_beginscan(pg_class, 0, false, 1, key);
+		heap_beginscan(pg_class, 0, SnapshotNow, 1, key);

 	if (!HeapScanIsValid(pg_class_scan))
 	{
@ -1598,7 +1598,7 @@ DefaultBuild(Relation heapRelation,
 	 */
 	scan = heap_beginscan(heapRelation, /* relation */
 						  0,	/* start at end */
-						  false,/* seeself */
+						  SnapshotNow,/* seeself */
 						  0,	/* number of keys */
 						  (ScanKey) NULL);		/* scan key */

@ -1812,7 +1812,7 @@ IndexIsUniqueNoCache(Oid indexId)
 						   (RegProcedure) F_OIDEQ,
 						   ObjectIdGetDatum(indexId));

-	scandesc = heap_beginscan(pg_index, 0, true, 1, skey);
+	scandesc = heap_beginscan(pg_index, 0, SnapshotSelf, 1, skey);

 	tuple = heap_getnext(scandesc, 0, NULL);
 	if (!HeapTupleIsValid(tuple))
--- a/src/backend/catalog/indexing.c
+++ b/src/backend/catalog/indexing.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.18 1998/06/15 19:28:09 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.19 1998/07/27 19:37:48 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -241,7 +241,7 @@ CatalogIndexFetchTuple(Relation heapRelation,
 			ItemPointer iptr;

 			iptr = &indexRes->heap_iptr;
-			tuple = heap_fetch(heapRelation, false, iptr, &buffer);
+			tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
 			pfree(indexRes);
 		}
 		else
@ -393,7 +393,7 @@ ProcedureNameIndexScan(Relation heapRelation,
 			ItemPointer iptr;

 			iptr = &indexRes->heap_iptr;
-			tuple = heap_fetch(heapRelation, false, iptr, &buffer);
+			tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
 			pfree(indexRes);
 			if (HeapTupleIsValid(tuple))
 			{
@ -458,7 +458,7 @@ ProcedureSrcIndexScan(Relation heapRelation, text *procSrc)
 		ItemPointer iptr;

 		iptr = &indexRes->heap_iptr;
-		tuple = heap_fetch(heapRelation, false, iptr, &buffer);
+		tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
 		pfree(indexRes);
 	}
 	else
--- a/src/backend/catalog/pg_operator.c
+++ b/src/backend/catalog/pg_operator.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_operator.c,v 1.25 1998/05/09 23:43:00 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_operator.c,v 1.26 1998/07/27 19:37:49 vadim Exp $
 *
 * NOTES
 *	  these routines moved here from commands/define.c and somewhat cleaned up.
@ -120,7 +120,7 @@ OperatorGetWithOpenRelation(Relation pg_operator_desc,
 	 */
 	pg_operator_scan = heap_beginscan(pg_operator_desc,
 									  0,
-									  true,
+									  SnapshotSelf,
 									  3,
 									  opKey);

@ -705,7 +705,7 @@ OperatorDef(char *operatorName,

 		pg_operator_scan = heap_beginscan(pg_operator_desc,
 										  0,
-										  true,
+										  SnapshotSelf,
 										  3,
 										  opKey);

@ -804,7 +804,7 @@ OperatorUpd(Oid baseId, Oid commId, Oid negId)

 	pg_operator_scan = heap_beginscan(pg_operator_desc,
 									  0,
-									  true,
+									  SnapshotSelf,
 									  1,
 									  opKey);

@ -894,7 +894,7 @@ OperatorUpd(Oid baseId, Oid commId, Oid negId)

 	pg_operator_scan = heap_beginscan(pg_operator_desc,
 									  0,
-									  true,
+									  SnapshotSelf,
 									  1,
 									  opKey);

--- a/src/backend/catalog/pg_type.c
+++ b/src/backend/catalog/pg_type.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.25 1998/06/15 19:28:10 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.26 1998/07/27 19:37:49 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -68,7 +68,7 @@ TypeGetWithOpenRelation(Relation pg_type_desc,

 	scan = heap_beginscan(pg_type_desc,
 						  0,
-						  true,
+						  SnapshotSelf,
 						  1,
 						  typeKey);

@ -470,7 +470,7 @@ TypeCreate(char *typeName,
 	typeKey[0].sk_argument = PointerGetDatum(typeName);
 	pg_type_scan = heap_beginscan(pg_type_desc,
 								  0,
-								  true,
+								  SnapshotSelf,
 								  1,
 								  typeKey);

--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.35 1998/07/09 03:28:44 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.36 1998/07/27 19:37:50 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -203,7 +203,7 @@ Async_Notify(char *relname)
 	lRel = heap_openr(ListenerRelationName);
 	tdesc = RelationGetTupleDescriptor(lRel);
 	RelationSetLockForWrite(lRel);
-	sRel = heap_beginscan(lRel, 0, false, 1, &key);
+	sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, &key);

 	nulls[0] = nulls[1] = nulls[2] = ' ';
 	repl[0] = repl[1] = repl[2] = ' ';
@ -283,7 +283,7 @@ Async_NotifyAtCommit()
 								   Int32GetDatum(1));
 			lRel = heap_openr(ListenerRelationName);
 			RelationSetLockForWrite(lRel);
-			sRel = heap_beginscan(lRel, 0, false, 1, &key);
+			sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, &key);
 			tdesc = RelationGetTupleDescriptor(lRel);

 			while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0, &b)))
@ -431,7 +431,7 @@ Async_Listen(char *relname, int pid)

 	/* is someone already listening.  One listener per relation */
 	tdesc = RelationGetTupleDescriptor(lDesc);
-	s = heap_beginscan(lDesc, 0, false, 0, (ScanKey) NULL);
+	s = heap_beginscan(lDesc, 0, SnapshotNow, 0, (ScanKey) NULL);
 	while (HeapTupleIsValid(htup = heap_getnext(s, 0, &b)))
 	{
 		d = heap_getattr(htup, Anum_pg_listener_relname, tdesc,
@ -577,7 +577,7 @@ Async_NotifyFrontEnd()
 	lRel = heap_openr(ListenerRelationName);
 	RelationSetLockForWrite(lRel);
 	tdesc = RelationGetTupleDescriptor(lRel);
-	sRel = heap_beginscan(lRel, 0, false, 2, key);
+	sRel = heap_beginscan(lRel, 0, SnapshotNow, 2, key);

 	nulls[0] = nulls[1] = nulls[2] = ' ';
 	repl[0] = repl[1] = repl[2] = ' ';
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@ -14,7 +14,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.25 1998/07/26 04:30:22 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.26 1998/07/27 19:37:50 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -43,11 +43,7 @@
 #include <utils/excid.h>
 #include <utils/mcxt.h>
 #include <catalog/pg_proc.h>
-#ifdef MULTIBYTE
-#include <catalog/pg_class_mb.h>
-#else
 #include <catalog/pg_class.h>
-#endif
 #include <optimizer/internal.h>
 #ifndef NO_SECURITY
 #include <utils/acl.h>
@ -358,7 +354,7 @@ rebuildheap(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
 	{

 		HeapTid = &ScanResult->heap_iptr;
-		LocalHeapTuple = heap_fetch(LocalOldHeap, false, HeapTid, &LocalBuffer);
+		LocalHeapTuple = heap_fetch(LocalOldHeap, SnapshotNow, HeapTid, &LocalBuffer);
 		OIDNewHeapInsert =
 			heap_insert(LocalNewHeap, LocalHeapTuple);
 		pfree(ScanResult);
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.28 1998/06/15 19:28:12 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.29 1998/07/27 19:37:51 vadim Exp $
 *
 * NOTES
 *	  The PortalExecutorHeapMemory crap needs to be eliminated
@ -438,7 +438,7 @@ PerformAddAttribute(char *relationName,
 		 * XXX use syscache here as an optimization
 		 */
 		key[1].sk_argument = (Datum) colDef->colname;
-		attsdesc = heap_beginscan(attrdesc, 0, false, 2, key);
+		attsdesc = heap_beginscan(attrdesc, 0, SnapshotNow, 2, key);


 		tup = heap_getnext(attsdesc, 0, (Buffer *) NULL);
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@ -6,7 +6,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.51 1998/07/26 04:30:23 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.52 1998/07/27 19:37:51 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -37,10 +37,6 @@
 #include "commands/trigger.h"
 #include <storage/fd.h>

-#ifdef MULTIBYTE
-#include "mb/pg_wchar.h"
-#endif
-
 #define ISOCTAL(c) (((c) >= '0') && ((c) <= '7'))
 #define VALUE(c) ((c) - '0')

@ -65,7 +61,7 @@ static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim, int *newline
 static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim);

 #endif
-static void CopyAttributeOut(FILE *fp, unsigned char *string, char *delim, int is_array);
+static void CopyAttributeOut(FILE *fp, char *string, char *delim, int is_array);
 static int	CountTuples(Relation relation);

 extern FILE *Pfout,
@ -225,7 +221,7 @@ CopyTo(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
 	int32		ntuples;
 	TupleDesc	tupDesc;

-	scandesc = heap_beginscan(rel, 0, false, 0, NULL);
+	scandesc = heap_beginscan(rel, 0, SnapshotNow, 0, NULL);

 	attr_count = rel->rd_att->natts;
 	attr = rel->rd_att->attrs;
@ -281,7 +277,7 @@ CopyTo(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
 				{
 					string = (char *) (*fmgr_faddr(&out_functions[i]))
 						(value, elements[i], typmod[i]);
-					CopyAttributeOut(fp, (unsigned char*)string, delim, attr[i]->attnelems);
+					CopyAttributeOut(fp, string, delim, attr[i]->attnelems);
 					pfree(string);
 				}
 				else
@ -908,7 +904,7 @@ GetIndexRelations(Oid main_relation_oid,
 	bool		isnull;

 	pg_index_rel = heap_openr(IndexRelationName);
-	scandesc = heap_beginscan(pg_index_rel, 0, false, 0, NULL);
+	scandesc = heap_beginscan(pg_index_rel, 0, SnapshotNow, 0, NULL);
 	tupDesc = RelationGetTupleDescriptor(pg_index_rel);

 	*n_indices = 0;
@ -1016,17 +1012,6 @@ CopyReadAttribute(FILE *fp, bool *isnull, char *delim)
 	char		c;
 	int			done = 0;
 	int			i = 0;
-#ifdef MULTIBYTE
-	int	mblen;
-	int	encoding;
-	unsigned char	s[2];
-	int	j;
-#endif
-
-#ifdef MULTIBYTE
-	encoding = pg_get_client_encoding();
-	s[1] = 0;
-#endif

 #ifdef COPY_PATCH
 	/* if last delimiter was a newline return a NULL attribute */
@ -1044,9 +1029,9 @@ CopyReadAttribute(FILE *fp, bool *isnull, char *delim)
 	while (!done)
 	{
 		c = getc(fp);
+
 		if (feof(fp))
 			return (NULL);
-
 		else if (c == '\\')
 		{
 			c = getc(fp);
@ -1127,55 +1112,21 @@ CopyReadAttribute(FILE *fp, bool *isnull, char *delim)
 #endif
 			done = 1;
 		}
-		if (!done) {
+		if (!done)
 			attribute[i++] = c;
-#ifdef MULTIBYTE
-			s[0] = c;
-			mblen = pg_encoding_mblen(encoding, s);
-			mblen--;
-			for(j=0;j<mblen;j++) {
-			  c = getc(fp);
-			  if (feof(fp))
-			    return (NULL);
-			  attribute[i++] = c;
-			}
-#endif
-		}
 		if (i == EXT_ATTLEN - 1)
 			elog(ERROR, "CopyReadAttribute - attribute length too long. line: %d", lineno);
 	}
 	attribute[i] = '\0';
-#ifdef MULTIBYTE
-	return(pg_client_to_server((unsigned char*)attribute, strlen(attribute)));
-#else
 	return (&attribute[0]);
-#endif
 }

 static void
-CopyAttributeOut(FILE *fp, unsigned char *server_string, char *delim, int is_array)
+CopyAttributeOut(FILE *fp, char *string, char *delim, int is_array)
 {
-        unsigned char           *string;
-	unsigned char		c;
-#ifdef MULTIBYTE
-	int	mblen;
-	int	encoding;
-	int	i;
-#endif
-
-#ifdef MULTIBYTE
-	string = pg_server_to_client(server_string, strlen(server_string));
-	encoding = pg_get_client_encoding();
-#else
-	string = server_string;
-#endif
+	char		c;

-#ifdef MULTIBYTE
-	for (; (mblen = pg_encoding_mblen(encoding, string)) &&
-	       ((c = *string) != '\0'); string += mblen)
-#else
 	for (; (c = *string) != '\0'; string++)
-#endif
 	{
 		if (c == delim[0] || c == '\n' ||
 			(c == '\\' && !is_array))
@ -1197,13 +1148,7 @@ CopyAttributeOut(FILE *fp, unsigned char *server_string, char *delim, int is_arr
 				fputc('\\', fp);
 			}
 		}
-#ifdef MULTIBYTE
-		for (i=0;i<mblen;i++) {
-			fputc(*(string+i), fp);
-		}
-#else
 		fputc(*string, fp);
-#endif
 	}
 }

@ -1221,7 +1166,7 @@ CountTuples(Relation relation)

 	int			i;

-	scandesc = heap_beginscan(relation, 0, false, 0, NULL);
+	scandesc = heap_beginscan(relation, 0, SnapshotNow, 0, NULL);

 	for (tuple = heap_getnext(scandesc, 0, NULL), i = 0;
 		 tuple != NULL;
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.17 1998/07/26 04:30:24 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.18 1998/07/27 19:37:52 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -22,11 +22,7 @@
 #include "access/htup.h"
 #include "access/relscan.h"
 #include "catalog/catname.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_database_mb.h"
-#else
 #include "catalog/pg_database.h"
-#endif
 #include "catalog/pg_shadow.h"
 #include "commands/dbcommands.h"
 #include "fmgr.h"
@ -47,11 +43,7 @@ static HeapTuple get_pg_dbtup(char *command, char *dbname, Relation dbrel);
 static void stop_vacuum(char *dbpath, char *dbname);

 void
-#ifdef MULTIBYTE
-createdb(char *dbname, char *dbpath, int encoding)
-#else
 createdb(char *dbname, char *dbpath)
-#endif
 {
 	Oid			db_id,
 				user_id;
@ -98,13 +90,8 @@ createdb(char *dbname, char *dbpath)
 			dbname, user_id, dbname);
 #endif

-#ifdef MULTIBYTE
-	sprintf(buf, "insert into pg_database (datname, datdba, encoding, datpath)"
-			" values (\'%s\', \'%d\', \'%d\', \'%s\');", dbname, user_id, encoding, loc);
-#else
 	sprintf(buf, "insert into pg_database (datname, datdba, datpath)"
 			" values (\'%s\', \'%d\', \'%s\');", dbname, user_id, loc);
-#endif

 	pg_exec_query(buf);
 }
@ -168,7 +155,7 @@ get_pg_dbtup(char *command, char *dbname, Relation dbrel)
 	ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname,
 						   F_NAMEEQ, NameGetDatum(dbname));

-	scan = heap_beginscan(dbrel, 0, false, 1, &scanKey);
+	scan = heap_beginscan(dbrel, 0, SnapshotNow, 1, &scanKey);
 	if (!HeapScanIsValid(scan))
 		elog(ERROR, "%s: cannot begin scan of pg_database.", command);

--- a/src/backend/commands/proclang.c
+++ b/src/backend/commands/proclang.c
@ -186,7 +186,7 @@ DropProceduralLanguage(DropPLangStmt *stmt)
 	ScanKeyEntryInitialize(&scanKeyData, 0, Anum_pg_language_lanname,
 						   F_NAMEEQ, PointerGetDatum(languageName));

-	scanDesc = heap_beginscan(rdesc, 0, false, 1, &scanKeyData);
+	scanDesc = heap_beginscan(rdesc, 0, SnapshotNow, 1, &scanKeyData);

 	tup = heap_getnext(scanDesc, 0, (Buffer *) NULL);

--- a/src/backend/commands/remove.c
+++ b/src/backend/commands/remove.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/remove.c,v 1.25 1998/06/15 19:28:16 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/remove.c,v 1.26 1998/07/27 19:37:53 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -97,7 +97,7 @@ RemoveOperator(char *operatorName,		/* operator name */
 						   ObjectIdGetDatum(typeId2));

 	relation = heap_openr(OperatorRelationName);
-	scan = heap_beginscan(relation, 0, false, 3, operatorKey);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 3, operatorKey);
 	tup = heap_getnext(scan, 0, &buffer);
 	if (HeapTupleIsValid(tup))
 	{
@ -165,7 +165,7 @@ SingleOpOperatorRemove(Oid typeOid)
 	for (i = 0; i < 3; ++i)
 	{
 		key[0].sk_attno = attnums[i];
-		sdesc = heap_beginscan(rdesc, 0, false, 1, key);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 1, key);
 		while (PointerIsValid(tup = heap_getnext(sdesc, 0, &buffer)))
 		{
 			ItemPointerCopy(&tup->t_ctid, &itemPointerData);
@ -214,7 +214,7 @@ AttributeAndRelationRemove(Oid typeOid)
 	oidptr->next = NULL;
 	optr = oidptr;
 	rdesc = heap_openr(AttributeRelationName);
-	sdesc = heap_beginscan(rdesc, 0, false, 1, key);
+	sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 1, key);
 	while (PointerIsValid(tup = heap_getnext(sdesc, 0, &buffer)))
 	{
 		ItemPointerCopy(&tup->t_ctid, &itemPointerData);
@ -235,7 +235,7 @@ AttributeAndRelationRemove(Oid typeOid)
 	while (PointerIsValid((char *) optr->next))
 	{
 		key[0].sk_argument = (Datum) (optr++)->reloid;
-		sdesc = heap_beginscan(rdesc, 0, false, 1, key);
+		sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 1, key);
 		tup = heap_getnext(sdesc, 0, &buffer);
 		if (PointerIsValid(tup))
 		{
@ -285,7 +285,7 @@ RemoveType(char *typeName)		/* type name to be removed */

 	typeKey[0].sk_argument = PointerGetDatum(typeName);

-	scan = heap_beginscan(relation, 0, false, 1, typeKey);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 1, typeKey);
 	tup = heap_getnext(scan, 0, (Buffer *) 0);
 	if (!HeapTupleIsValid(tup))
 	{
@ -303,7 +303,7 @@ RemoveType(char *typeName)		/* type name to be removed */
 	shadow_type = makeArrayTypeName(typeName);
 	typeKey[0].sk_argument = NameGetDatum(shadow_type);

-	scan = heap_beginscan(relation, 0, false,
+	scan = heap_beginscan(relation, 0, SnapshotNow,
 						  1, (ScanKey) typeKey);
 	tup = heap_getnext(scan, 0, (Buffer *) 0);

@ -390,7 +390,7 @@ RemoveFunction(char *functionName,		/* function name to be removed */
 	key[0].sk_nargs = key[0].sk_func.fn_nargs;

 	relation = heap_openr(ProcedureRelationName);
-	scan = heap_beginscan(relation, 0, false, 1, key);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 1, key);

 	do
 	{							/* hope this is ok because it's indexed */
@ -493,7 +493,7 @@ RemoveAggregate(char *aggName, char *aggType)
 						   ObjectIdGetDatum(basetypeID));

 	relation = heap_openr(AggregateRelationName);
-	scan = heap_beginscan(relation, 0, false, 2, aggregateKey);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 2, aggregateKey);
 	tup = heap_getnext(scan, 0, (Buffer *) 0);
 	if (!HeapTupleIsValid(tup))
 	{
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@ -119,7 +119,7 @@ CreateTrigger(CreateTrigStmt *stmt)
 	RelationSetLockForWrite(tgrel);
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ, rel->rd_id);
-	tgscan = heap_beginscan(tgrel, 0, false, 1, &key);
+	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
 	while (tuple = heap_getnext(tgscan, 0, (Buffer *) NULL), PointerIsValid(tuple))
 	{
 		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
@ -275,7 +275,7 @@ DropTrigger(DropTrigStmt *stmt)
 	RelationSetLockForWrite(tgrel);
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ, rel->rd_id);
-	tgscan = heap_beginscan(tgrel, 0, false, 1, &key);
+	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
 	while (tuple = heap_getnext(tgscan, 0, (Buffer *) NULL), PointerIsValid(tuple))
 	{
 		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
@ -340,7 +340,7 @@ RelationRemoveTriggers(Relation rel)
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ, rel->rd_id);

-	tgscan = heap_beginscan(tgrel, 0, false, 1, &key);
+	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);

 	while (tup = heap_getnext(tgscan, 0, (Buffer *) NULL), PointerIsValid(tup))
 		heap_delete(tgrel, &tup->t_ctid);
@ -391,7 +391,7 @@ RelationBuildTriggers(Relation relation)
 			break;

 		iptr = &indexRes->heap_iptr;
-		tuple = heap_fetch(tgrel, false, iptr, &buffer);
+		tuple = heap_fetch(tgrel, SnapshotNow, iptr, &buffer);
 		pfree(indexRes);
 		if (!HeapTupleIsValid(tuple))
 			continue;
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@ -20,11 +20,7 @@

 #include <miscadmin.h>
 #include <catalog/catname.h>
-#ifdef MULTIBYTE
-#include <catalog/pg_database_mb.h>
-#else
 #include <catalog/pg_database.h>
-#endif
 #include <catalog/pg_shadow.h>
 #include <libpq/crypt.h>
 #include <access/heapam.h>
@ -138,7 +134,7 @@ DefineUser(CreateUserStmt *stmt)
 	 */
 	RelationSetLockForWrite(pg_shadow_rel);

-	scan = heap_beginscan(pg_shadow_rel, false, false, 0, NULL);
+	scan = heap_beginscan(pg_shadow_rel, false, SnapshotNow, 0, NULL);
 	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0, &buffer)))
 	{
 		datum = heap_getattr(tuple, Anum_pg_shadow_usename, pg_shadow_dsc, &n);
@ -268,7 +264,7 @@ AlterUser(AlterUserStmt *stmt)
 	 */
 	RelationSetLockForWrite(pg_shadow_rel);

-	scan = heap_beginscan(pg_shadow_rel, false, false, 0, NULL);
+	scan = heap_beginscan(pg_shadow_rel, false, SnapshotNow, 0, NULL);
 	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0, &buffer)))
 	{
 		datum = heap_getattr(tuple, Anum_pg_shadow_usename, pg_shadow_dsc, &n);
@ -397,7 +393,7 @@ RemoveUser(char *user)
 	 */
 	RelationSetLockForWrite(pg_shadow_rel);

-	scan = heap_beginscan(pg_shadow_rel, false, false, 0, NULL);
+	scan = heap_beginscan(pg_shadow_rel, false, SnapshotNow, 0, NULL);
 	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0, &buffer)))
 	{
 		datum = heap_getattr(tuple, Anum_pg_shadow_usename, pg_dsc, &n);
@ -428,7 +424,7 @@ RemoveUser(char *user)
 	pg_rel = heap_openr(DatabaseRelationName);
 	pg_dsc = RelationGetTupleDescriptor(pg_rel);

-	scan = heap_beginscan(pg_rel, false, false, 0, NULL);
+	scan = heap_beginscan(pg_rel, false, SnapshotNow, 0, NULL);
 	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0, &buffer)))
 	{
 		datum = heap_getattr(tuple, Anum_pg_database_datdba, pg_dsc, &n);
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.68 1998/07/26 04:30:25 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.69 1998/07/27 19:37:53 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -27,11 +27,7 @@
 #include "catalog/catalog.h"
 #include "catalog/catname.h"
 #include "catalog/index.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_class_mb.h"
-#else
 #include "catalog/pg_class.h"
-#endif
 #include "catalog/pg_index.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_statistic.h"
@ -297,7 +293,7 @@ vc_getrels(NameData *VacRelP)
 	pgclass = heap_openr(RelationRelationName);
 	pgcdesc = RelationGetTupleDescriptor(pgclass);

-	pgcscan = heap_beginscan(pgclass, false, false, 1, &pgckey);
+	pgcscan = heap_beginscan(pgclass, false, SnapshotNow, 1, &pgckey);

 	while (HeapTupleIsValid(pgctup = heap_getnext(pgcscan, 0, &buf)))
 	{
@ -404,7 +400,7 @@ vc_vacone(Oid relid, bool analyze, List *va_cols)

 	pgclass = heap_openr(RelationRelationName);
 	pgcdesc = RelationGetTupleDescriptor(pgclass);
-	pgcscan = heap_beginscan(pgclass, false, false, 1, &pgckey);
+	pgcscan = heap_beginscan(pgclass, false, SnapshotNow, 1, &pgckey);

 	/*
 	 * Race condition -- if the pg_class tuple has gone away since the
@ -1776,7 +1772,7 @@ vc_updstats(Oid relid, int npages, int ntups, bool hasindex, VRelStats *vacrelst
 						   ObjectIdGetDatum(relid));

 	rd = heap_openr(RelationRelationName);
-	rsdesc = heap_beginscan(rd, false, false, 1, &rskey);
+	rsdesc = heap_beginscan(rd, false, SnapshotNow, 1, &rskey);

 	if (!HeapTupleIsValid(rtup = heap_getnext(rsdesc, 0, &rbuf)))
 		elog(ERROR, "pg_class entry for relid %d vanished during vacuuming",
@ -1799,7 +1795,7 @@ vc_updstats(Oid relid, int npages, int ntups, bool hasindex, VRelStats *vacrelst
 		ScanKeyEntryInitialize(&askey, 0, Anum_pg_attribute_attrelid,
 							   F_INT4EQ, relid);

-		asdesc = heap_beginscan(ad, false, false, 1, &askey);
+		asdesc = heap_beginscan(ad, false, SnapshotNow, 1, &askey);

 		while (HeapTupleIsValid(atup = heap_getnext(asdesc, 0, &abuf)))
 		{
@ -1946,10 +1942,10 @@ vc_delhilowstats(Oid relid, int attcnt, int *attnums)
 		ScanKeyEntryInitialize(&pgskey, 0x0, Anum_pg_statistic_starelid,
 							   F_OIDEQ,
 							   ObjectIdGetDatum(relid));
-		pgsscan = heap_beginscan(pgstatistic, false, false, 1, &pgskey);
+		pgsscan = heap_beginscan(pgstatistic, false, SnapshotNow, 1, &pgskey);
 	}
 	else
-		pgsscan = heap_beginscan(pgstatistic, false, false, 0, NULL);
+		pgsscan = heap_beginscan(pgstatistic, false, SnapshotNow, 0, NULL);

 	while (HeapTupleIsValid(pgstup = heap_getnext(pgsscan, 0, NULL)))
 	{
@ -2158,7 +2154,7 @@ vc_getindices(Oid relid, int *nindices, Relation **Irel)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(relid));

-	pgiscan = heap_beginscan(pgindex, false, false, 1, &pgikey);
+	pgiscan = heap_beginscan(pgindex, false, SnapshotNow, 1, &pgikey);

 	while (HeapTupleIsValid(pgitup = heap_getnext(pgiscan, 0, NULL)))
 	{
--- a/src/backend/executor/execAmi.c
+++ b/src/backend/executor/execAmi.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execAmi.c,v 1.23 1998/07/16 01:49:18 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execAmi.c,v 1.24 1998/07/27 19:37:54 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -56,7 +56,7 @@

 static Pointer
 ExecBeginScan(Relation relation, int nkeys, ScanKey skeys,
-			  bool isindex, ScanDirection dir);
+			  bool isindex, ScanDirection dir, Snapshot snapshot);
 static Relation ExecOpenR(Oid relationOid, bool isindex);

 /* ----------------------------------------------------------------
@ -81,6 +81,7 @@ ExecOpenScanR(Oid relOid,
 			  ScanKey skeys,
 			  bool isindex,
 			  ScanDirection dir,
+			  Snapshot snapshot,
 			  Relation *returnRelation, /* return */
 			  Pointer *returnScanDesc)	/* return */
 {
@ -99,7 +100,8 @@ ExecOpenScanR(Oid relOid,
 							 nkeys,
 							 skeys,
 							 isindex,
-							 dir);
+							 dir,
+							 snapshot);

 	if (returnRelation != NULL)
 		*returnRelation = relation;
@ -153,7 +155,8 @@ ExecBeginScan(Relation relation,
 			  int nkeys,
 			  ScanKey skeys,
 			  bool isindex,
-			  ScanDirection dir)
+			  ScanDirection dir,
+			  Snapshot snapshot)
 {
 	Pointer		scanDesc;

@ -178,7 +181,7 @@ ExecBeginScan(Relation relation,
 	{
 		scanDesc = (Pointer) heap_beginscan(relation,
 											ScanDirectionIsBackward(dir),
-											false,
+											snapshot,
 											nkeys,
 											skeys);
 	}
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@ -26,7 +26,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.50 1998/07/20 16:14:13 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.51 1998/07/27 19:37:55 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -124,6 +124,8 @@ ExecutorStart(QueryDesc *queryDesc, EState *estate)
 			palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 		memset(estate->es_param_exec_vals, 0, queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 	}
+	
+	estate->es_snapshot = SnapshotNow;

 	result = InitPlan(queryDesc->operation,
 					  queryDesc->parsetree,
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.33 1998/07/20 16:14:13 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.34 1998/07/27 19:37:56 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -750,7 +750,7 @@ ExecOpenIndices(Oid resultRelationOid,
 	 */
 	indexSd = heap_beginscan(indexRd,	/* scan desc */
 							 false,		/* scan backward flag */
-							 false,		/* see self */
+							 SnapshotNow,	/* NOW snapshot */
 							 1, /* number scan keys */
 							 &key);		/* scan keys */

--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.18 1998/06/15 19:28:22 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.19 1998/07/27 19:37:57 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -85,7 +85,8 @@ IndexNext(IndexScan *node)
 	EState	   *estate;
 	CommonScanState *scanstate;
 	IndexScanState *indexstate;
-	ScanDirection direction;
+	ScanDirection	direction;
+	Snapshot		snapshot;
 	int			indexPtr;
 	IndexScanDescPtr scanDescs;
 	IndexScanDesc scandesc;
@ -101,6 +102,7 @@ IndexNext(IndexScan *node)
 	 */
 	estate = node->scan.plan.state;
 	direction = estate->es_direction;
+	snapshot = estate->es_snapshot;
 	scanstate = node->scan.scanstate;
 	indexstate = node->indxstate;
 	indexPtr = indexstate->iss_IndexPtr;
@ -122,7 +124,8 @@ IndexNext(IndexScan *node)
 	 */
 	while ((result = index_getnext(scandesc, direction)) != NULL)
 	{
-		tuple = heap_fetch(heapRelation, false, &result->heap_iptr, &buffer);
+		tuple = heap_fetch(heapRelation, snapshot, 
+							&result->heap_iptr, &buffer);
 		/* be tidy */
 		pfree(result);

@ -920,6 +923,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
 				  (ScanKey) NULL,		/* scan key */
 				  0,			/* is index */
 				  direction,	/* scan direction */
+				  estate->es_snapshot,	/* */
 				  &currentRelation,		/* return: rel desc */
 				  (Pointer *) &currentScanDesc);		/* return: scan desc */

@ -958,6 +962,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
 						  scanKeys[i],	/* scan key */
 						  true, /* is index */
 						  direction,	/* scan direction */
+						  estate->es_snapshot,
 						  &(relationDescs[i]),	/* return: rel desc */
 						  (Pointer *) &(scanDescs[i]));
 			/* return: scan desc */
--- a/src/backend/executor/nodeMaterial.c
+++ b/src/backend/executor/nodeMaterial.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeMaterial.c,v 1.13 1998/02/26 04:31:28 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeMaterial.c,v 1.14 1998/07/27 19:37:57 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -139,8 +139,7 @@ ExecMaterial(Material *node)
 		 */
 		currentScanDesc = heap_beginscan(currentRelation,		/* relation */
 										 ScanDirectionIsBackward(dir),
-		/* bkwd flag */
-										 false, /* seeself */
+										 SnapshotSelf,	/* seeself */
 										 0,		/* num scan keys */
 										 NULL); /* scan keys */
 		matstate->csstate.css_currentRelation = currentRelation;
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSeqscan.c,v 1.10 1998/06/15 19:28:22 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSeqscan.c,v 1.11 1998/07/27 19:37:57 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -181,6 +181,7 @@ InitScanRelation(SeqScan *node, EState *estate,
 					  NULL,		/* scan key */
 					  0,		/* is index */
 					  direction,/* scan direction */
+					  estate->es_snapshot,
 					  &currentRelation, /* return: rel desc */
 					  (Pointer *) &currentScanDesc);	/* return: scan desc */

--- a/src/backend/executor/nodeTee.c
+++ b/src/backend/executor/nodeTee.c
@ -15,7 +15,7 @@
 *		ExecEndTee
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/Attic/nodeTee.c,v 1.18 1998/06/15 19:28:23 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/Attic/nodeTee.c,v 1.19 1998/07/27 19:37:57 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -226,10 +226,11 @@ ExecCountSlotsTee(Tee *node)
 static void
 initTeeScanDescs(Tee *node)
 {
-	TeeState   *teeState;
-	Relation	bufferRel;
-	ScanDirection dir;
-	MemoryContext orig;
+	TeeState	   *teeState;
+	Relation		bufferRel;
+	ScanDirection	dir;
+	Snapshot		snapshot;
+	MemoryContext	orig;

 	teeState = node->teestate;
 	if (teeState->tee_leftScanDesc && teeState->tee_rightScanDesc)
@ -241,23 +242,24 @@ initTeeScanDescs(Tee *node)
 	bufferRel = teeState->tee_bufferRel;
 	dir = ((Plan *) node)->state->es_direction; /* backwards not handled
 												 * yet XXX */
+	snapshot = ((Plan *) node)->state->es_snapshot;

 	if (teeState->tee_leftScanDesc == NULL)
 	{
 		teeState->tee_leftScanDesc = heap_beginscan(bufferRel,
 											ScanDirectionIsBackward(dir),
-													false,		/* seeself */
-													0,	/* num scan keys */
-													NULL		/* scan keys */
+											snapshot,
+											0,	/* num scan keys */
+											NULL		/* scan keys */
 			);
 	}
 	if (teeState->tee_rightScanDesc == NULL)
 	{
 		teeState->tee_rightScanDesc = heap_beginscan(bufferRel,
 											ScanDirectionIsBackward(dir),
-													 false,		/* seeself */
-													 0, /* num scan keys */
-													 NULL		/* scan keys */
+											snapshot,
+											0, /* num scan keys */
+											NULL		/* scan keys */
 			);
 	}

--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.17 1998/07/18 04:22:31 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.18 1998/07/27 19:37:58 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -979,7 +979,7 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 	 * will be used to find the associated strategy numbers for the test.
 	 * --Nels, Jan '93
 	 */
-	scan = heap_beginscan(relation, false, false, 2, entry);
+	scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);
 	tuple = heap_getnext(scan, false, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 	{
@ -1010,7 +1010,7 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(clause_op));

-	scan = heap_beginscan(relation, false, false, 3, entry);
+	scan = heap_beginscan(relation, false, SnapshotNow, 3, entry);
 	tuple = heap_getnext(scan, false, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 	{
@ -1042,7 +1042,7 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 						   F_INT2EQ,
 						   Int16GetDatum(test_strategy));

-	scan = heap_beginscan(relation, false, false, 3, entry);
+	scan = heap_beginscan(relation, false, SnapshotNow, 3, entry);
 	tuple = heap_getnext(scan, false, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 	{
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.17 1998/06/15 19:28:49 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.18 1998/07/27 19:38:00 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -148,7 +148,7 @@ index_info(Query *root, bool first, int relid, IdxInfoRetval *info)
 							   ObjectIdGetDatum(indrelid));

 		relation = heap_openr(IndexRelationName);
-		scan = heap_beginscan(relation, 0, false,
+		scan = heap_beginscan(relation, 0, SnapshotNow,
 							  1, &indexKey);
 	}
 	if (!HeapScanIsValid(scan))
@ -413,7 +413,7 @@ find_inheritance_children(Oid inhparent)

 	key[0].sk_argument = ObjectIdGetDatum((Oid) inhparent);
 	relation = heap_openr(InheritsRelationName);
-	scan = heap_beginscan(relation, 0, false, 1, key);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 1, key);
 	while (HeapTupleIsValid(inheritsTuple =
 							heap_getnext(scan, 0,
 										 (Buffer *) NULL)))
@ -449,7 +449,7 @@ VersionGetParents(Oid verrelid)
 	key[0].sk_nargs = key[0].sk_func.fn_nargs;
 	relation = heap_openr(VersionRelationName);
 	key[0].sk_argument = ObjectIdGetDatum(verrelid);
-	scan = heap_beginscan(relation, 0, false, 1, key);
+	scan = heap_beginscan(relation, 0, SnapshotNow, 1, key);
 	for (;;)
 	{
 		versionTuple = heap_getnext(scan, 0,
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.23 1998/07/20 19:53:51 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.24 1998/07/27 19:38:02 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -547,7 +547,7 @@ func_get_candidates(char *funcname, int nargs)
 			ItemPointer iptr;

 			iptr = &indexRes->heap_iptr;
-			tuple = heap_fetch(heapRelation, false, iptr, &buffer);
+			tuple = heap_fetch(heapRelation, SnapshotNow, iptr, &buffer);
 			pfree(indexRes);
 			if (HeapTupleIsValid(tuple))
 			{
@ -1024,7 +1024,7 @@ find_inheritors(Oid relid, Oid **supervec)
 							   F_OIDEQ,
 							   ObjectIdGetDatum(relid));

-		inhscan = heap_beginscan(inhrel, 0, false, 1, &skey);
+		inhscan = heap_beginscan(inhrel, 0, SnapshotNow, 1, &skey);

 		while (HeapTupleIsValid(inhtup = heap_getnext(inhscan, 0, &buf)))
 		{
--- a/src/backend/parser/parse_oper.c
+++ b/src/backend/parser/parse_oper.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.13 1998/06/15 19:28:55 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.14 1998/07/27 19:38:04 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -108,7 +108,7 @@ binary_oper_get_candidates(char *opname,
 	pg_operator_desc = heap_openr(OperatorRelationName);
 	pg_operator_scan = heap_beginscan(pg_operator_desc,
 									  0,
-									  TRUE,
+									  SnapshotSelf,	/* ??? */
 									  nkeys,
 									  opKey);

@ -655,7 +655,7 @@ printf("unary_oper_get_candidates: start scan for '%s'\n", op);
 	pg_operator_desc = heap_openr(OperatorRelationName);
 	pg_operator_scan = heap_beginscan(pg_operator_desc,
 									  0,
-									  TRUE,
+									  SnapshotSelf,	/* ??? */
 									  2,
 									  opKey);

--- a/src/backend/rewrite/rewriteRemove.c
+++ b/src/backend/rewrite/rewriteRemove.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.14 1998/04/26 04:07:07 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.15 1998/07/27 19:38:08 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -87,7 +87,7 @@ RemoveRewriteRule(char *ruleName)
 	ScanKeyEntryInitialize(&scanKeyData, 0, Anum_pg_rewrite_rulename,
 						   F_NAMEEQ, NameGetDatum(ruleName));
 	scanDesc = heap_beginscan(RewriteRelation,
-							  0, false, 1, &scanKeyData);
+							  0, SnapshotNow, 1, &scanKeyData);

 	tuple = heap_getnext(scanDesc, 0, (Buffer *) NULL);

@ -161,7 +161,7 @@ RelationRemoveRules(Oid relid)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(relid));
 	scanDesc = heap_beginscan(RewriteRelation,
-							  0, false, 1, &scanKeyData);
+							  0, SnapshotNow, 1, &scanKeyData);

 	for (;;)
 	{
--- a/src/backend/rewrite/rewriteSupport.c
+++ b/src/backend/rewrite/rewriteSupport.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteSupport.c,v 1.23 1998/07/26 04:30:38 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteSupport.c,v 1.24 1998/07/27 19:38:09 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -16,11 +16,7 @@
 #include "access/heapam.h"
 #include "catalog/catname.h"
 #include "catalog/indexing.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_class_mb.h"
-#else
 #include "catalog/pg_class.h"
-#endif
 #include "catalog/pg_rewrite.h"
 #include "fmgr.h"
 #include "nodes/parsenodes.h"
@ -109,7 +105,7 @@ IsDefinedRewriteRule(char *ruleName)
 	ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_rewrite_rulename,
 					   F_NAMEEQ, PointerGetDatum(ruleName));
 	scanDesc = heap_beginscan(RewriteRelation,
-							  0, false, 1, &scanKey);
+							  0, SnapshotNow, 1, &scanKey);

 	tuple = heap_getnext(scanDesc, 0, (Buffer *) NULL);

--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.28 1998/07/21 06:17:35 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.29 1998/07/27 19:38:10 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -585,7 +585,6 @@ ShmemInitStruct(char *name, unsigned long size, bool *foundPtr)
 	return (structPtr);
 }

-
 /*
 * TransactionIdIsInProgress -- is given transaction running by some backend
 *
@ -625,3 +624,75 @@ TransactionIdIsInProgress(TransactionId xid)
 	elog(ERROR, "TransactionIdIsInProgress: ShmemIndex corrupted");
 	return (false);
 }
+
+#ifdef LowLevelLocking
+/*
+ * GetSnapshotData -- returns information about running transactions.
+ *
+ * InvalidTransactionId is used as terminator in snapshot->xip array.
+ * If serialized is true then XID >= current xact ID will not be
+ * placed in array. Current xact ID are never placed there (just
+ * to reduce its length, xmin/xmax may be equal to cid).
+ * MyProc->xmin will be setted if equal to InvalidTransactionId.
+ * 
+ * Yet another strange func for this place...	- vadim 07/21/98
+ */
+Snapshot
+GetSnapshotData(bool serialized)
+{
+	Snapshot		snapshot = (Snapshot) malloc(sizeof(SnapshotData));
+	TransactionId	snapshot->xip = (TransactionId*) 
+									malloc(32 * sizeof(TransactionId));
+	ShmemIndexEnt  *result;
+	PROC		   *proc;
+	TransactionId	cid = GetCurrentTransactionId();
+	uint			count = 0;
+	unit			free = 31;
+
+	Assert(ShmemIndex);
+	
+	snapshot->xmax = cid;
+	snapshot->xmin = cid;
+
+	SpinAcquire(ShmemIndexLock);
+
+	hash_seq((HTAB *) NULL);
+	while ((result = (ShmemIndexEnt *) hash_seq(ShmemIndex)) != NULL)
+	{
+		if (result == (ShmemIndexEnt *) TRUE)
+		{
+			if (MyProc->xmin == InvalidTransactionId)
+				MyProc->xmin = snapshot->xmin;
+			SpinRelease(ShmemIndexLock);
+			snapshot->xip[count] = InvalidTransactionId;
+			return (snapshot);
+		}
+		if (result->location == INVALID_OFFSET ||
+			strncmp(result->key, "PID ", 4) != 0)
+			continue;
+		proc = (PROC *) MAKE_PTR(result->location);
+		if (proc == MyProc || proc->xid < FirstTransactionId ||
+				serialized && proc->xid >= cid)
+			continue;
+		if (proc->xid < snapshot->xmin)
+			snapshot->xmin = proc->xid;
+		else if (proc->xid > snapshot->xmax)
+			snapshot->xmax = proc->xid;
+		if (free == 0)
+		{
+			snapshot->xip = (TransactionId*) realloc(snapshot->xip, 
+								(count + 33) * sizeof(TransactionId));
+			free = 32;
+		}
+		snapshot->xip[count] = proc->xid;
+		free--;
+		count++;
+	}
+
+	SpinRelease(ShmemIndexLock);
+	free(snapshot->xip);
+	free(snapshot);
+	elog(ERROR, "GetSnapshotData: ShmemIndex corrupted");
+	return (NULL);
+}
+#endif
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.31 1998/07/21 04:17:24 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.32 1998/07/27 19:38:11 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -656,9 +656,13 @@ inv_fetchtup(LargeObjectDesc *obj_desc, Buffer *bufP)
 			 * For time travel, we need to use the actual time qual here,
 			 * rather that NowTimeQual.  We currently have no way to pass
 			 * a time qual in.
+			 *
+			 * This is now valid for snapshot !!!
+			 * And should be fixed in some way...	- vadim 07/28/98
+			 * 
 			 */

-			htup = heap_fetch(obj_desc->heap_r, false,
+			htup = heap_fetch(obj_desc->heap_r, SnapshotNow,
 							  &(res->heap_iptr), bufP);

 		} while (htup == (HeapTuple) NULL);
@ -669,7 +673,7 @@ inv_fetchtup(LargeObjectDesc *obj_desc, Buffer *bufP)
 	}
 	else
 	{
-		htup = heap_fetch(obj_desc->heap_r, false,
+		htup = heap_fetch(obj_desc->heap_r, SnapshotNow,
 						  &(obj_desc->htid), bufP);
 	}

@ -1235,7 +1239,7 @@ _inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln)
 		if (buf != InvalidBuffer)
 			ReleaseBuffer(buf);

-		htup = heap_fetch(hreln, false, &(res->heap_iptr), &buf);
+		htup = heap_fetch(hreln, SnapshotNow, &(res->heap_iptr), &buf);
 		pfree(res);

 	} while (!HeapTupleIsValid(htup));
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.39 1998/06/30 02:33:32 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.40 1998/07/27 19:38:15 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -46,7 +46,7 @@
 *		This is so that we can support more backends. (system-wide semaphore
 *		sets run out pretty fast.)				  -ay 4/95
 *
- * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.39 1998/06/30 02:33:32 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.40 1998/07/27 19:38:15 vadim Exp $
 */
 #include <sys/time.h>
 #include <unistd.h>
@ -252,6 +252,9 @@ InitProcess(IPCKey key)
 	MyProc->pid = MyProcPid;
 #endif
 	MyProc->xid = InvalidTransactionId;
+#ifdef LowLevelLocking
+	MyProc->xmin = InvalidTransactionId;
+#endif

 	/* ----------------
 	 * Start keeping spin lock stats from here on.	Any botch before
@ -479,11 +482,13 @@ ProcSleep(PROC_QUEUE *waitQueue,
 	MyProc->token = token;
 	MyProc->waitLock = lock;

+#ifndef LowLevelLocking
 	/* -------------------
 	 * currently, we only need this for the ProcWakeup routines
 	 * -------------------
 	 */
 	TransactionIdStore((TransactionId) GetCurrentTransactionId(), &MyProc->xid);
+#endif

 	/* -------------------
 	 * assume that these two operations are atomic (because
--- a/src/backend/utils/adt/not_in.c
+++ b/src/backend/utils/adt/not_in.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/not_in.c,v 1.9 1998/06/15 19:29:36 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/not_in.c,v 1.10 1998/07/27 19:38:18 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -72,8 +72,8 @@ int4notin(int16 not_in_arg, char *relation_and_attr)
 	/* the last argument should be a ScanKey, not an integer! - jolly */
 	/* it looks like the arguments are out of order, too */
 	/* but skeyData is never initialized! does this work?? - ay 2/95 */
-	scan_descriptor = heap_beginscan(relation_to_scan, false, false, 0,
-									 &skeyData);
+	scan_descriptor = heap_beginscan(relation_to_scan, false, SnapshotNow, 
+									 0, &skeyData);

 	retval = true;

--- a/src/backend/utils/adt/regproc.c
+++ b/src/backend/utils/adt/regproc.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regproc.c,v 1.20 1998/07/20 16:57:01 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/regproc.c,v 1.21 1998/07/27 19:38:19 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -55,7 +55,7 @@ regprocin(char *proname)
 						   (RegProcedure) F_NAMEEQ,
 						   (Datum) proname);

-	procscan = heap_beginscan(proc, 0, false, 1, &key);
+	procscan = heap_beginscan(proc, 0, SnapshotNow, 1, &key);
 	if (!HeapScanIsValid(procscan))
 	{
 		heap_close(proc);
@ -111,7 +111,7 @@ regprocout(RegProcedure proid)
 						   (RegProcedure) F_INT4EQ,
 						   (Datum) proid);

-	procscan = heap_beginscan(proc, 0, false, 1, &key);
+	procscan = heap_beginscan(proc, 0, SnapshotNow, 1, &key);
 	if (!HeapScanIsValid(procscan))
 	{
 		heap_close(proc);
@ -189,7 +189,7 @@ oid8types(Oid (*oidArray)[])
 								   (RegProcedure) F_INT4EQ,
 								   (Datum) *sp);

-			typescan = heap_beginscan(type, 0, false, 1, &key);
+			typescan = heap_beginscan(type, 0, SnapshotNow, 1, &key);
 			if (!HeapScanIsValid(typescan))
 			{
 				heap_close(type);
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@ -12,7 +12,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.19 1998/06/15 19:29:37 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.20 1998/07/27 19:38:20 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -349,7 +349,7 @@ gethilokey(Oid relid,
 	key[0].sk_argument = ObjectIdGetDatum(relid);
 	key[1].sk_argument = Int16GetDatum((int16) attnum);
 	key[2].sk_argument = ObjectIdGetDatum(opid);
-	sdesc = heap_beginscan(rdesc, 0, false, 3, key);
+	sdesc = heap_beginscan(rdesc, 0, SnapshotNow, 3, key);
 	tuple = heap_getnext(sdesc, 0, (Buffer *) NULL);
 	if (!HeapTupleIsValid(tuple))
 	{
--- a/src/backend/utils/adt/sets.c
+++ b/src/backend/utils/adt/sets.c
@ -9,7 +9,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.14 1998/07/20 16:57:02 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.15 1998/07/27 19:38:21 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -123,7 +123,7 @@ SetDefine(char *querystr, char *typename)
 		oidKey[0].sk_argument = ObjectIdGetDatum(setoid);
 		pg_proc_scan = heap_beginscan(procrel,
 									  0,
-									  true,
+									  SnapshotSelf,
 									  1,
 									  oidKey);
 		tup = heap_getnext(pg_proc_scan, 0, &buffer);
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.30 1998/07/20 16:57:03 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.31 1998/07/27 19:38:22 vadim Exp $
 *
 * Notes:
 *		XXX This needs to use exception.h to handle recovery when
@ -994,7 +994,7 @@ SearchSysCache(struct catcache * cache,
 		 */
 		MemoryContextSwitchTo(oldcxt);

-		sd = heap_beginscan(relation, 0, false,
+		sd = heap_beginscan(relation, 0, SnapshotNow,
 							cache->cc_nkeys, cache->cc_skey);

 		/* should this buffer be ReleaseBuffer'd?  --djm 8/20/96 */
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.43 1998/07/26 04:30:57 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.44 1998/07/27 19:38:23 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -53,11 +53,7 @@
 #include "catalog/indexing.h"
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_attrdef.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_attribute_mb.h"
-#else
 #include "catalog/pg_attribute.h"
-#endif
 #include "catalog/pg_index.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_class.h"
@ -376,7 +372,7 @@ scan_pg_rel_seq(RelationBuildDescInfo buildinfo)
 	if (!IsInitProcessingMode())
 		RelationSetLockForRead(pg_class_desc);
 	pg_class_scan =
-		heap_beginscan(pg_class_desc, 0, false, 1, &key);
+		heap_beginscan(pg_class_desc, 0, SnapshotNow, 1, &key);
 	pg_class_tuple = heap_getnext(pg_class_scan, 0, &buf);

 	/* ----------------
@ -546,7 +542,7 @@ build_tupdesc_seq(RelationBuildDescInfo buildinfo,
 	 */
 	pg_attribute_desc = heap_openr(AttributeRelationName);
 	pg_attribute_scan =
-		heap_beginscan(pg_attribute_desc, 0, false, 1, &key);
+		heap_beginscan(pg_attribute_desc, 0, SnapshotNow, 1, &key);

 	/* ----------------
 	 *	add attribute data to relation->rd_att
@ -717,7 +713,7 @@ RelationBuildRuleLock(Relation relation)
 	 */
 	pg_rewrite_desc = heap_openr(RewriteRelationName);
 	pg_rewrite_scan =
-		heap_beginscan(pg_rewrite_desc, 0, false, 1, &key);
+		heap_beginscan(pg_rewrite_desc, 0, SnapshotNow, 1, &key);
 	pg_rewrite_tupdesc =
 		RelationGetTupleDescriptor(pg_rewrite_desc);

@ -1705,7 +1701,7 @@ AttrDefaultFetch(Relation relation)
 			break;

 		iptr = &indexRes->heap_iptr;
-		tuple = heap_fetch(adrel, false, iptr, &buffer);
+		tuple = heap_fetch(adrel, SnapshotNow, iptr, &buffer);
 		pfree(indexRes);
 		if (!HeapTupleIsValid(tuple))
 			continue;
@ -1793,7 +1789,7 @@ RelCheckFetch(Relation relation)
 			break;

 		iptr = &indexRes->heap_iptr;
-		tuple = heap_fetch(rcrel, false, iptr, &buffer);
+		tuple = heap_fetch(rcrel, SnapshotNow, iptr, &buffer);
 		pfree(indexRes);
 		if (!HeapTupleIsValid(tuple))
 			continue;
--- a/src/backend/utils/misc/database.c
+++ b/src/backend/utils/misc/database.c
@ -7,7 +7,7 @@
 *
 *
 * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/misc/Attic/database.c,v 1.13 1998/07/26 04:31:07 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/misc/Attic/database.c,v 1.14 1998/07/27 19:38:26 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -22,12 +22,7 @@
 #include "access/heapam.h"
 #include "access/xact.h"
 #include "catalog/catname.h"
-#ifdef MULTIBYTE
-#include "catalog/pg_database_mb.h"
-#include "mb/pg_wchar.h"
-#else
 #include "catalog/pg_database.h"
-#endif
 #include "fmgr.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@ -62,7 +57,7 @@ GetDatabaseInfo(char *name, Oid *owner, char *path)
 	ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname,
 						   F_NAMEEQ, NameGetDatum(name));

-	scan = heap_beginscan(dbrel, 0, false, 1, &scanKey);
+	scan = heap_beginscan(dbrel, 0, SnapshotNow, 1, &scanKey);
 	if (!HeapScanIsValid(scan))
 		elog(ERROR, "GetDatabaseInfo: cannot begin scan of %s", DatabaseRelationName);

@ -184,11 +179,7 @@ ExpandDatabasePath(char *dbpath)
 * --------------------------------
 */
 void
-#ifdef MULTIBYTE
-GetRawDatabaseInfo(char *name, Oid *owner, Oid *db_id, char *path, int *encoding)
-#else
 GetRawDatabaseInfo(char *name, Oid *owner, Oid *db_id, char *path)
-#endif
 {
 	int			dbfd;
 	int			fileflags;
@ -275,25 +266,14 @@ GetRawDatabaseInfo(char *name, Oid *owner, Oid *db_id, char *path)
 			 * means of getting at sys cat attrs.
 			 */
 			tup_db = (Form_pg_database) GETSTRUCT(tup);
-#ifdef MULTIBYTE
-			/* get encoding from template database.
-			   This is the "default for default" for
-			   create database command.
-			   */
-			if (strcmp("template1",tup_db->datname.data) == 0)
-			{
-				SetTemplateEncoding(tup_db->encoding);
-			}
-#endif
+
 			if (strcmp(name, tup_db->datname.data) == 0)
 			{
 				*db_id = tup->t_oid;
 				strncpy(path, VARDATA(&(tup_db->datpath)),
 						(VARSIZE(&(tup_db->datpath)) - VARHDRSZ));
 				*(path + VARSIZE(&(tup_db->datpath)) - VARHDRSZ) = '\0';
-#ifdef MULTIBYTE
-				*encoding = tup_db->encoding;
-#endif
+
 				goto done;
 			}
 		}
--- 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 1.33 1998/06/15 18:39:53 momjian Exp $
+ * $Id: heapam.h,v 1.34 1998/07/27 19:38:29 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -18,6 +18,7 @@
 #include <access/relscan.h>
 #include <storage/block.h>
 #include <utils/rel.h>
+#include <utils/tqual.h>

 /* ----------------------------------------------------------------
 *				heap access method statistics
@ -247,11 +248,11 @@ extern Relation heap_openr(char *relationName);
 extern void heap_close(Relation relation);
 extern HeapScanDesc
 heap_beginscan(Relation relation, int atend,
-			   bool seeself, unsigned nkeys, ScanKey key);
+			   Snapshot snapshot, unsigned nkeys, ScanKey key);
 extern void heap_rescan(HeapScanDesc sdesc, bool scanFromEnd, ScanKey key);
 extern void heap_endscan(HeapScanDesc sdesc);
 extern HeapTuple heap_getnext(HeapScanDesc scandesc, int backw, Buffer *b);
-extern HeapTuple heap_fetch(Relation relation, bool seeself, ItemPointer tid, Buffer *b);
+extern HeapTuple heap_fetch(Relation relation, Snapshot snapshot, ItemPointer tid, Buffer *b);
 extern Oid	heap_insert(Relation relation, HeapTuple tup);
 extern int	heap_delete(Relation relation, ItemPointer tid);
 extern int
--- a/src/include/access/relscan.h
+++ b/src/include/access/relscan.h
@ -6,7 +6,7 @@
 *
 * Copyright (c) 1994, Regents of the University of California
 *
- * $Id: relscan.h,v 1.10 1997/11/24 05:09:39 momjian Exp $
+ * $Id: relscan.h,v 1.11 1998/07/27 19:38:29 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -16,6 +16,7 @@
 #include <storage/buf.h>
 #include <utils/rel.h>
 #include <access/htup.h>
+#include <utils/tqual.h>

 typedef ItemPointerData MarkData;

@ -32,8 +33,8 @@ typedef struct HeapScanDescData
 	ItemPointerData rs_mctid;	/* marked current tid */
 	ItemPointerData rs_mntid;	/* marked next tid */
 	ItemPointerData rs_mcd;		/* marked current delta XXX ??? */
+	Snapshot	rs_snapshot;	/* snapshot to see */
 	bool		rs_atend;		/* restart scan at end? */
-	bool		rs_seeself;		/* see self or not */
 	uint16		rs_cdelta;		/* current delta in chain */
 	uint16		rs_nkeys;		/* number of attributes in keys */
 	ScanKey		rs_key;			/* key descriptors */
--- 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 1.13 1998/04/24 14:42:55 momjian Exp $
+ * $Id: xact.h,v 1.14 1998/07/27 19:38:30 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -22,14 +22,22 @@
 */
 typedef struct TransactionStateData
 {
-	TransactionId transactionIdData;
-	CommandId	commandId;
-	CommandId	scanCommandId;
-	AbsoluteTime startTime;
-	int			state;
-	int			blockState;
+	TransactionId		transactionIdData;
+	CommandId			commandId;
+	CommandId			scanCommandId;
+	AbsoluteTime		startTime;
+	int					state;
+	int					blockState;
 } TransactionStateData;

+/*
+ * Xact isolation levels
+ */
+#define	XACT_DIRTY_READ			0		/* not implemented */
+#define	XACT_READ_COMMITTED		1
+#define	XACT_REPEATABLE_READ	2		/* not implemented */
+#define	XACT_SERIALIZED			3
+
 /* ----------------
 *		transaction states
 * ----------------
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@ -6,7 +6,7 @@
 *
 * Copyright (c) 1994, Regents of the University of California
 *
- * $Id: executor.h,v 1.22 1998/04/24 14:43:07 momjian Exp $
+ * $Id: executor.h,v 1.23 1998/07/27 19:38:32 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -61,8 +61,8 @@
 */
 extern void
 ExecOpenScanR(Oid relOid, int nkeys, ScanKey skeys, bool isindex,
-			  ScanDirection dir, Relation *returnRelation,
-			  Pointer *returnScanDesc);
+			  ScanDirection dir, Snapshot snapshot, 
+			  Relation *returnRelation, Pointer *returnScanDesc);
 extern void ExecCloseR(Plan *node);
 extern void ExecReScan(Plan *node, ExprContext *exprCtxt, Plan *parent);
 extern HeapScanDesc
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@ -6,7 +6,7 @@
 *
 * Copyright (c) 1994, Regents of the University of California
 *
- * $Id: execnodes.h,v 1.15 1998/02/26 04:41:55 momjian Exp $
+ * $Id: execnodes.h,v 1.16 1998/07/27 19:38:34 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -194,19 +194,20 @@ typedef struct JunkFilter
 */
 typedef struct EState
 {
-	NodeTag		type;
-	ScanDirection es_direction;
-	List	   *es_range_table;
-	RelationInfo *es_result_relation_info;
-	Relation	es_into_relation_descriptor;
-	ParamListInfo es_param_list_info;
-	ParamExecData *es_param_exec_vals;	/* this is for subselects */
-	int			es_BaseId;
-	TupleTable	es_tupleTable;
-	JunkFilter *es_junkFilter;
-	int		   *es_refcount;
-	uint32		es_processed;	/* # of tuples processed */
-	Oid			es_lastoid;		/* last oid processed (by INSERT) */
+	NodeTag			type;
+	ScanDirection	es_direction;
+	Snapshot		es_snapshot;
+	List		   *es_range_table;
+	RelationInfo   *es_result_relation_info;
+	Relation		es_into_relation_descriptor;
+	ParamListInfo	es_param_list_info;
+	ParamExecData  *es_param_exec_vals;	/* this is for subselects */
+	int				es_BaseId;
+	TupleTable		es_tupleTable;
+	JunkFilter	   *es_junkFilter;
+	int			   *es_refcount;
+	uint32			es_processed;	/* # of tuples processed */
+	Oid				es_lastoid;		/* last oid processed (by INSERT) */
 } EState;

 /* ----------------
--- 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 1.12 1998/06/30 02:33:33 momjian Exp $
+ * $Id: proc.h,v 1.13 1998/07/27 19:38:38 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -44,6 +44,14 @@ 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 */
 	int			pid;			/* This procs process id */
--- a/src/include/utils/tqual.h
+++ b/src/include/utils/tqual.h
@ -3,10 +3,11 @@
 * tqual.h--
 *	  POSTGRES "time" qualification definitions.
 *
+ *	  Should be moved/renamed...	- vadim 07/28/98
 *
 * Copyright (c) 1994, Regents of the University of California
 *
- * $Id: tqual.h,v 1.12 1998/04/24 14:43:33 momjian Exp $
+ * $Id: tqual.h,v 1.13 1998/07/27 19:38:40 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -15,6 +16,20 @@

 #include <access/htup.h>

+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 */
+} 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 TransactionId HeapSpecialTransactionId;
 extern CommandId HeapSpecialCommandId;

@ -25,13 +40,13 @@ extern CommandId HeapSpecialCommandId;
 * Note:
 *		Assumes heap tuple is valid.
 */
-#define HeapTupleSatisfiesVisibility(tuple, seeself) \
+#define HeapTupleSatisfiesVisibility(tuple, snapshot) \
 ( \
 	TransactionIdEquals((tuple)->t_xmax, AmiTransactionId) ? \
 		false \
 	: \
 	( \
-		((seeself) == true || heapisoverride()) ? \
+		(IsSnapshotSelf(snapshot) || heapisoverride()) ? \
 			HeapTupleSatisfiesItself(tuple) \
 		: \
 			HeapTupleSatisfiesNow(tuple) \