diff --git a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroduceGroupByCombinerRule.java b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroduceGroupByCombinerRule.java
index 5c5fdb1..a8864fe 100644
--- a/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroduceGroupByCombinerRule.java
+++ b/algebricks/algebricks-rewriter/src/main/java/edu/uci/ics/hyracks/algebricks/rewriter/rules/IntroduceGroupByCombinerRule.java
@@ -38,7 +38,6 @@
         if (context.checkIfInDontApplySet(this, op)) {
             return false;
         }
-        context.addToDontApplySet(this, op);
         if (op.getOperatorTag() != LogicalOperatorTag.GROUP) {
             return false;
         }
@@ -86,6 +85,7 @@
         opRef3.setValue(newGbyOp);
         typeGby(newGbyOp, context);
         typeGby(gbyOp, context);
+    	context.addToDontApplySet(this, op);
         return true;
     }