diff --git a/iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/schema/ClusterSchemaManager.java b/iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/schema/ClusterSchemaManager.java
index 0e2069fe704f..b7a0688fcdb7 100644
--- a/iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/schema/ClusterSchemaManager.java
+++ b/iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/schema/ClusterSchemaManager.java
@@ -246,6 +246,7 @@ public TSStatus alterDatabase(
       }
     }
 
+    // For table model's ttl
     if (databaseSchema.isIsTableModel() && databaseSchema.isSetTTL()) {
       return configManager.getProcedureManager().alterDatabase(databaseSchema, isGeneratedByPipe);
     }