diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/base/LogicalOperatorDeepCopyVisitor.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/base/LogicalOperatorDeepCopyVisitor.java
index 8b537a7..a573df3 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/base/LogicalOperatorDeepCopyVisitor.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/algebra/base/LogicalOperatorDeepCopyVisitor.java
@@ -23,6 +23,7 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.DistinctOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.EmptyTupleSourceOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ExchangeOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ExtensionOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.GroupByOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.IndexInsertDeleteOperator;
 import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator;
@@ -49,8 +50,6 @@
 import edu.uci.ics.hyracks.algebricks.core.algebra.properties.FunctionalDependency;
 import edu.uci.ics.hyracks.algebricks.core.algebra.visitors.ILogicalOperatorVisitor;
 
-
-
 public class LogicalOperatorDeepCopyVisitor implements ILogicalOperatorVisitor<ILogicalOperator, ILogicalOperator> {
     private final Counter counter;
     private final LogicalExpressionDeepCopyVisitor exprDeepCopyVisitor;
@@ -378,4 +377,10 @@
     public ILogicalOperator visitSinkOperator(SinkOperator op, ILogicalOperator arg) {
         throw new UnsupportedOperationException();
     }
+
+    @Override
+    public ILogicalOperator visitExtensionOperator(ExtensionOperator op, ILogicalOperator arg)
+            throws AlgebricksException {
+        throw new UnsupportedOperationException();
+    }
 }