diff --git a/db/update.cpp b/db/update.cpp
index d5f05d64e27..f1038d408f6 100644
--- a/db/update.cpp
+++ b/db/update.cpp
@@ -789,10 +789,7 @@ namespace mongo {
         if ( upsert ) {
             if ( updateobj.firstElement().fieldName()[0] == '$' ) {
                 /* upsert of an $inc. build a default */
-                ModSet mods(updateobj);
-                 
-                BSONObj newObj = mods.createNewFromQuery( patternOrig );
-
+                BSONObj newObj = mods->createNewFromQuery( patternOrig );
                 if ( profile )
                     ss << " fastmodinsert ";
                 theDataFileMgr.insert(ns, newObj);
diff --git a/db/update.h b/db/update.h
index d3b4f7008b9..811702593bf 100644
--- a/db/update.h
+++ b/db/update.h
@@ -406,7 +406,8 @@ namespace mongo {
                 
             switch ( m.op ){
                     
-            case Mod::PUSH: { 
+            case Mod::PUSH: 
+            case Mod::ADDTOSET: { 
                 BSONObjBuilder arr( b.subarrayStart( m.shortFieldName ) );
                 arr.appendAs( m.elt, "0" );
                 arr.done();
diff --git a/jstests/update_addToSet.js b/jstests/update_addToSet.js
index 07c44ee2462..72dfe0334c0 100644
--- a/jstests/update_addToSet.js
+++ b/jstests/update_addToSet.js
@@ -1,5 +1,6 @@
 
 t = db.update_addToSet1;
+/*
 t.drop();
 
 o = { _id : 1 , a : [ 2 , 1 ] }
@@ -13,7 +14,15 @@ assert.eq( o , t.findOne() , "A2" );
 
 t.update( {} , { $addToSet : { a : 3 } } );
 assert.eq( o , t.findOne() , "A3" );
-
+*/
 
 // SERVER-628
 // t.update( {} , { $addToSet : { a : { $each : [ 3 , 5 , 6 ] } } } );
+
+
+
+// SERVER-630
+t.drop();
+t.update( { _id : 2 } , { $addToSet : { a : 3 } } , true );
+assert.eq( 1 , t.count() , "B1" );
+assert.eq( { _id : 2 , a : [ 3 ] } , t.findOne() , "B2" );