diff --git a/pkg/sink/codec/open/codec.go b/pkg/sink/codec/open/codec.go
index 073713b46..18e43b8cb 100644
--- a/pkg/sink/codec/open/codec.go
+++ b/pkg/sink/codec/open/codec.go
@@ -44,6 +44,9 @@ func encodeRowChangedEvent(e *commonEvent.RowEvent, config *common.Config, large
 		keyWriter.WriteStringField("tbl", e.TableInfo.GetTableName())
 		keyWriter.WriteIntField("t", int(common.MessageTypeRow))
 
+		if largeMessageOnlyHandleKeyColumns {
+			keyWriter.WriteBoolField("ohk", true)
+		}
 		if claimCheckLocationName != "" {
 			keyWriter.WriteBoolField("ohk", false)
 			keyWriter.WriteStringField("ccl", claimCheckLocationName)
diff --git a/tests/integration_tests/open_protocol_handle_key_only/run.sh b/tests/integration_tests/open_protocol_handle_key_only/run.sh
index 6be9ec9c2..b8544208e 100644
--- a/tests/integration_tests/open_protocol_handle_key_only/run.sh
+++ b/tests/integration_tests/open_protocol_handle_key_only/run.sh
@@ -20,7 +20,7 @@ function run() {
 
 	cd $WORK_DIR
 
-	TOPIC_NAME="open-protocol-handle-key-only"
+	TOPIC_NAME="open-protocol-handle-key-only-$RANDOM"
 
 	# record tso before we create tables to skip the system table DDLs
 	start_ts=$(run_cdc_cli_tso_query ${UP_PD_HOST_1} ${UP_PD_PORT_1})