diff --git a/br/pkg/lightning/mydump/loader.go b/br/pkg/lightning/mydump/loader.go
index d670d9bfcb3f9..b3a0079e9a658 100644
--- a/br/pkg/lightning/mydump/loader.go
+++ b/br/pkg/lightning/mydump/loader.go
@@ -69,13 +69,14 @@ func (m *MDDatabaseMeta) GetSchema(ctx context.Context, store storage.ExternalSt
 
 // MDTableMeta contains some parsed metadata for a table in the source by MyDumper Loader.
 type MDTableMeta struct {
-	DB           string
-	Name         string
-	SchemaFile   FileInfo
-	DataFiles    []FileInfo
-	charSet      string
-	TotalSize    int64
-	IndexRatio   float64
+	DB         string
+	Name       string
+	SchemaFile FileInfo
+	DataFiles  []FileInfo
+	charSet    string
+	TotalSize  int64
+	IndexRatio float64
+	// default to true, and if we do precheck, this var is updated using data sampling result, so it's not accurate.
 	IsRowOrdered bool
 }
 
diff --git a/executor/importer/table_import.go b/executor/importer/table_import.go
index 4dae8bb785a5f..49cf1d6f5c365 100644
--- a/executor/importer/table_import.go
+++ b/executor/importer/table_import.go
@@ -129,6 +129,7 @@ func newTableImporter(ctx context.Context, e *LoadDataController) (ti *tableImpo
 		DB:        e.DBName,
 		Name:      e.Table.Meta().Name.O,
 		DataFiles: e.toMyDumpFiles(),
+		// todo: set IsRowOrdered.
 	}
 	dataDivideCfg := &mydump.DataDivideConfig{
 		ColumnCnt:         len(e.Table.Meta().Columns),