diff --git a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/grouped/GroupedAccumulator.java b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/grouped/GroupedAccumulator.java
index 8f628718f68d..a39ef2f2d0fb 100644
--- a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/grouped/GroupedAccumulator.java
+++ b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/grouped/GroupedAccumulator.java
@@ -36,6 +36,10 @@ public interface GroupedAccumulator {
 
   void evaluateFinal(int groupId, ColumnBuilder columnBuilder);
 
+  /**
+   * This interface will be used for order by in agg function (not implemented), implementations are
+   * all empty now.
+   */
   void prepareFinal();
 
   void reset();