bail out or clause checking if we do an unpredicted table scan

db/queryoptimizer.cpp

@@ -641,7 +641,8 @@ namespace mongo {
     _honorRecordedPlan( honorRecordedPlan ),
     _bestGuessOnly( bestGuessOnly ),
     _hint( ( hint && !hint->eoo() ) ? hint->wrap() : BSONObj() ),
-    _mayYield( mayYield )
+    _mayYield( mayYield ),
+    _tableScanned()
     {
         if ( !order.isEmpty() || !min.isEmpty() || !max.isEmpty() || !_fros.getSpecial().empty() ) {
             _or = false;
@@ -670,6 +671,9 @@ namespace mongo {
         BSONElement hintElt = _hint.firstElement();
         _currentQps.reset( new QueryPlanSet( _ns, frs, _query, BSONObj(), &hintElt, _honorRecordedPlan, BSONObj(), BSONObj(), _bestGuessOnly, _mayYield ) );
         shared_ptr< QueryOp > ret( _currentQps->runOp( op ) );
+        if ( ret->qp().willScanTable() ) {
+            _tableScanned = true;
+        }
         _fros.popOrClause();
         return ret;
     }