diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/properties/ChildOutputPropertyDeriver.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/properties/ChildOutputPropertyDeriver.java
index 7b0546a9e0fdc7c..e0b3e05a7500d2a 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/properties/ChildOutputPropertyDeriver.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/properties/ChildOutputPropertyDeriver.java
@@ -133,6 +133,16 @@ public PhysicalProperties visitPhysicalFileScan(PhysicalFileScan fileScan, PlanC
         return PhysicalProperties.STORAGE_ANY;
     }
 
+    /**
+     * TODO return ANY after refactor coordinator
+     * return STORAGE_ANY not ANY, in order to generate distribute on jdbc scan.
+     * select * from (select * from external.T) as A union all (select * from external.T)
+     * if visitPhysicalJdbcScan returns ANY, the plan is
+     * union
+     *  |--- JDBCSCAN
+     *  +--- JDBCSCAN
+     *  this breaks coordinator assumption that one fragment has at most only one scan.
+     */
     @Override
     public PhysicalProperties visitPhysicalJdbcScan(PhysicalJdbcScan jdbcScan, PlanContext context) {
         return PhysicalProperties.STORAGE_ANY;