[PATCH] Explicit null dereferenced (src/backend/access/heap/heaptoast.c)

diff --git a/src/backend/access/heap/heaptoast.c b/src/backend/access/heap/heaptoast.c
index 584f101dd9..1c57cc515e 100644
--- a/src/backend/access/heap/heaptoast.c
+++ b/src/backend/access/heap/heaptoast.c
@@ -133,8 +133,6 @@ heap_toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup,
 
 	Assert(numAttrs <= MaxHeapAttributeNumber);
 	heap_deform_tuple(newtup, tupleDesc, toast_values, toast_isnull);
-	if (oldtup != NULL)
-		heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull);
 
 	/* ----------
 	 * Prepare for toasting
@@ -143,6 +141,7 @@ heap_toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup,
 	ttc.ttc_rel = rel;
 	ttc.ttc_values = toast_values;
 	ttc.ttc_isnull = toast_isnull;
+	ttc.ttc_attr = toast_attr;
 	if (oldtup == NULL)
 	{
 		ttc.ttc_oldvalues = NULL;
@@ -150,10 +149,10 @@ heap_toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup,
 	}
 	else
 	{
+		heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull);
 		ttc.ttc_oldvalues = toast_oldvalues;
 		ttc.ttc_oldisnull = toast_oldisnull;
 	}
-	ttc.ttc_attr = toast_attr;
 	toast_tuple_init(&ttc);
 
 	/* ----------
diff --git a/src/backend/access/table/toast_helper.c b/src/backend/access/table/toast_helper.c
index 739b6ae990..ca5d6f5fc6 100644
--- a/src/backend/access/table/toast_helper.c
+++ b/src/backend/access/table/toast_helper.c
@@ -48,62 +48,11 @@ toast_tuple_init(ToastTupleContext *ttc)
 
 	for (i = 0; i < numAttrs; i++)
 	{
-		Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
-		struct varlena *old_value;
-		struct varlena *new_value;
+		Form_pg_attribute att;
 
 		ttc->ttc_attr[i].tai_colflags = 0;
 		ttc->ttc_attr[i].tai_oldexternal = NULL;
 
-		if (ttc->ttc_oldvalues != NULL)
-		{
-			/*
-			 * For UPDATE get the old and new values of this attribute
-			 */
-			old_value =
-				(struct varlena *) DatumGetPointer(ttc->ttc_oldvalues[i]);
-			new_value =
-				(struct varlena *) DatumGetPointer(ttc->ttc_values[i]);
-
-			/*
-			 * If the old value is stored on disk, check if it has changed so
-			 * we have to delete it later.
-			 */
-			if (att->attlen == -1 && !ttc->ttc_oldisnull[i] &&
-				VARATT_IS_EXTERNAL_ONDISK(old_value))
-			{
-				if (ttc->ttc_isnull[i] ||
-					!VARATT_IS_EXTERNAL_ONDISK(new_value) ||
-					memcmp((char *) old_value, (char *) new_value,
-						   VARSIZE_EXTERNAL(old_value)) != 0)
-				{
-					/*
-					 * The old external stored value isn't needed any more
-					 * after the update
-					 */
-					ttc->ttc_attr[i].tai_colflags |= TOASTCOL_NEEDS_DELETE_OLD;
-					ttc->ttc_flags |= TOAST_NEEDS_DELETE_OLD;
-				}
-				else
-				{
-					/*
-					 * This attribute isn't changed by this update so we reuse
-					 * the original reference to the old value in the new
-					 * tuple.
-					 */
-					ttc->ttc_attr[i].tai_colflags |= TOASTCOL_IGNORE;
-					continue;
-				}
-			}
-		}
-		else
-		{
-			/*
-			 * For INSERT simply get the new value
-			 */
-			new_value = (struct varlena *) DatumGetPointer(ttc->ttc_values[i]);
-		}
-
 		/*
 		 * Handle NULL attributes
 		 */
@@ -114,11 +63,19 @@ toast_tuple_init(ToastTupleContext *ttc)
 			continue;
 		}
 
+		att = TupleDescAttr(tupleDesc, i);
 		/*
 		 * Now look at varlena attributes
 		 */
 		if (att->attlen == -1)
 		{
+		    struct varlena *new_value;
+
+		    /*
+		     * For INSERT simply get the new value
+		     */
+		    new_value = (struct varlena *) DatumGetPointer(ttc->ttc_values[i]);
+			
 			/*
 			 * If the table's attribute says PLAIN always, force it so.
 			 */
@@ -158,6 +115,56 @@ toast_tuple_init(ToastTupleContext *ttc)
 			ttc->ttc_attr[i].tai_colflags |= TOASTCOL_IGNORE;
 		}
 	}
+
+    if (ttc->ttc_oldvalues != NULL)
+	{		
+	    for (i = 0; i < numAttrs; i++)
+	    {
+		    Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
+		    struct varlena *old_value;
+
+		    /*
+		     * For UPDATE get the old value of this attribute
+		     */
+		    old_value =
+			    (struct varlena *) DatumGetPointer(ttc->ttc_oldvalues[i]);
+
+		    /*
+		     * If the old value is stored on disk, check if it has changed so
+		     * we have to delete it later.
+		     */
+		    if (att->attlen == -1 && !ttc->ttc_oldisnull[i] &&
+			    VARATT_IS_EXTERNAL_ONDISK(old_value))
+		    {
+		        struct varlena *new_value;
+
+		        new_value =
+			        (struct varlena *) DatumGetPointer(ttc->ttc_values[i]);
+
+			    if (ttc->ttc_isnull[i] ||
+				    !VARATT_IS_EXTERNAL_ONDISK(new_value) ||
+				     memcmp((char *) old_value, (char *) new_value,
+					       VARSIZE_EXTERNAL(old_value)) != 0)
+			    {
+				    /*
+				     * The old external stored value isn't needed any more
+				     * after the update
+				     */
+				    ttc->ttc_attr[i].tai_colflags |= TOASTCOL_NEEDS_DELETE_OLD;
+				    ttc->ttc_flags |= TOAST_NEEDS_DELETE_OLD;
+			    }
+			    else
+			    {
+				    /*
+				     * This attribute isn't changed by this update so we reuse
+				     * the original reference to the old value in the new
+				     * tuple.
+				     */
+				    ttc->ttc_attr[i].tai_colflags |= TOASTCOL_IGNORE;
+			    }
+		    }
+	    }
+	}
 }