diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 1ea78ec863..39f6d223eb 100644
--- 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 1.43 1999/05/25 16:07:04 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.44 1999/06/10 14:17:05 vadim Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1152,8 +1152,13 @@ l1:
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 		if (TransactionIdDidAbort(xwait))
 			goto l1;
-		/* concurrent xact committed */
-		Assert(tp.t_data->t_xmax == xwait);
+		/* 
+		 * xwait is committed but if xwait had just marked
+		 * the tuple for update then some other xaction could 
+		 * update this tuple before we got to this point.
+		 */
+		if (tp.t_data->t_xmax != xwait)
+			goto l1;
 		if (!(tp.t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
 			tp.t_data->t_infomask |= HEAP_XMAX_COMMITTED;
@@ -1242,8 +1247,13 @@ l2:
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 		if (TransactionIdDidAbort(xwait))
 			goto l2;
-		/* concurrent xact committed */
-		Assert(oldtup.t_data->t_xmax == xwait);
+		/* 
+		 * xwait is committed but if xwait had just marked
+		 * the tuple for update then some other xaction could 
+		 * update this tuple before we got to this point.
+		 */
+		if (oldtup.t_data->t_xmax != xwait)
+			goto l2;
 		if (!(oldtup.t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
 			oldtup.t_data->t_infomask |= HEAP_XMAX_COMMITTED;
@@ -1359,8 +1369,13 @@ l3:
 		LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
 		if (TransactionIdDidAbort(xwait))
 			goto l3;
-		/* concurrent xact committed */
-		Assert(tuple->t_data->t_xmax == xwait);
+		/* 
+		 * xwait is committed but if xwait had just marked
+		 * the tuple for update then some other xaction could 
+		 * update this tuple before we got to this point.
+		 */
+		if (tuple->t_data->t_xmax != xwait)
+			goto l3;
 		if (!(tuple->t_data->t_infomask & HEAP_XMAX_COMMITTED))
 		{
 			tuple->t_data->t_infomask |= HEAP_XMAX_COMMITTED;
diff --git a/src/backend/access/transam/transam.c b/src/backend/access/transam/transam.c
index fe1d57d769..03bb786f4b 100644
--- a/src/backend/access/transam/transam.c
+++ b/src/backend/access/transam/transam.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.26 1999/05/25 16:07:45 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.27 1999/06/10 14:17:06 vadim Exp $
  *
  * NOTES
  *	  This file contains the high level access-method interface to the
@@ -172,8 +172,14 @@ TransactionLogTest(TransactionId transactionId, /* transaction id to test */
 
 	if (!fail)
 	{
-		TransactionIdStore(transactionId, &cachedTestXid);
-		cachedTestXidStatus = xidstatus;
+		/*
+		 * DO NOT cache status for transactions in unknown state !!!
+		 */
+		if (xidstatus == XID_COMMIT || xidstatus == XID_ABORT)
+		{
+			TransactionIdStore(transactionId, &cachedTestXid);
+			cachedTestXidStatus = xidstatus;
+		}
 		return (bool) (status == xidstatus);
 	}
 
@@ -576,12 +582,3 @@ TransactionIdAbort(TransactionId transactionId)
 
 	TransactionLogUpdate(transactionId, XID_ABORT);
 }
-
-void
-TransactionIdFlushCache()
-{
-
-	TransactionIdStore(AmiTransactionId, &cachedTestXid);
-	cachedTestXidStatus = XID_COMMIT;
-
-}
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index d03136b508..4689a2f82e 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.40 1999/06/06 20:19:34 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.41 1999/06/10 14:17:06 vadim Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -514,8 +514,6 @@ CommandCounterIncrement()
 	AtCommit_Cache();
 	AtStart_Cache();
 
-	TransactionIdFlushCache();
-
 }
 
 void
@@ -822,7 +820,6 @@ StartTransaction()
 {
 	TransactionState s = CurrentTransactionState;
 
-	TransactionIdFlushCache();
 	FreeXactSnapshot();
 	XactIsoLevel = DefaultXactIsoLevel;
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 7c1a8cd600..bfc9094b48 100644
--- 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 1.107 1999/06/06 20:19:34 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.108 1999/06/10 14:17:07 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1351,6 +1351,8 @@ vc_rpfheap(VRelStats *vacrelstats, Relation onerel,
 						if (!ItemIdIsUsed(Pitemid))
 							elog(ERROR, "Parent itemid marked as unused");
 						Ptp.t_data = (HeapTupleHeader) PageGetItem(Ppage, Pitemid);
+						Assert(ItemPointerEquals(&(vtld.new_tid),
+												&(Ptp.t_data->t_ctid)));
 						Assert(Ptp.t_data->t_xmax == tp.t_data->t_xmin);
 
 #ifdef NOT_USED			/* I'm not sure that this will wotk properly... */
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 9b7a41b4cb..f0b397dbea 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.53 1999/05/29 03:58:43 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.54 1999/06/10 14:17:09 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2007,7 +2007,8 @@ LockBuffer(Buffer buffer, int mode)
 		else if (BufferLocks[buffer - 1] & BL_W_LOCK)
 		{
 			Assert(buf->w_lock);
-			Assert(buf->r_locks == 0 && !buf->ri_lock);
+			Assert(buf->r_locks == 0);
+			Assert(!buf->ri_lock);
 			Assert(!(BufferLocks[buffer - 1] & (BL_R_LOCK | BL_RI_LOCK)))
 				buf->w_lock = false;
 			BufferLocks[buffer - 1] &= ~BL_W_LOCK;
diff --git a/src/backend/storage/lmgr/lmgr.c b/src/backend/storage/lmgr/lmgr.c
index f7ab4acffb..58ee47fe61 100644
--- a/src/backend/storage/lmgr/lmgr.c
+++ b/src/backend/storage/lmgr/lmgr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.26 1999/05/31 01:48:13 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.27 1999/06/10 14:17:11 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -324,8 +324,6 @@ XactLockTableWait(TransactionId xid)
 	LockAcquire(LockTableId, &tag, ShareLock);
 	LockRelease(LockTableId, &tag, ShareLock);
 
-	TransactionIdFlushCache();
-
 	/*
 	 * Transaction was committed/aborted/crashed - we have to update
 	 * pg_log if transaction is still marked as running.
diff --git a/src/include/access/transam.h b/src/include/access/transam.h
index 23fc2b59f0..2551278f12 100644
--- a/src/include/access/transam.h
+++ b/src/include/access/transam.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: transam.h,v 1.21 1999/05/25 22:42:35 momjian Exp $
+ * $Id: transam.h,v 1.22 1999/06/10 14:17:12 vadim Exp $
  *
  *	 NOTES
  *		Transaction System Version 101 now support proper oid
@@ -145,7 +145,6 @@ extern bool TransactionIdDidCommit(TransactionId transactionId);
 extern bool TransactionIdDidAbort(TransactionId transactionId);
 extern void TransactionIdCommit(TransactionId transactionId);
 extern void TransactionIdAbort(TransactionId transactionId);
-extern void TransactionIdFlushCache(void);
 
 /* in transam/transsup.c */
 extern void AmiTransactionOverride(bool flag);