diff --git a/ddl/index.go b/ddl/index.go
index 14b89c64aa..97bcd38b0e 100644
--- a/ddl/index.go
+++ b/ddl/index.go
@@ -587,9 +587,9 @@ func (w *addIndexWorker) fetchRowColVals(txn kv.Transaction, taskRange reorgInde
 // backfillIndexInTxn will add w.batchCnt indices once, default value of w.batchCnt is 128.
 // TODO: make w.batchCnt can be modified by system variable.
 func (w *addIndexWorker) backfillIndexInTxn(handleRange reorgIndexTask) (nextHandle int64, addedCount, scanCount int, errInTxn error) {
-	addedCount = 0
-	scanCount = 0
 	errInTxn = kv.RunInNewTxn(w.sessCtx.GetStore(), true, func(txn kv.Transaction) error {
+		addedCount = 0
+		scanCount = 0
 		txn.SetOption(kv.Priority, kv.PriorityLow)
 		idxRecords, handleOutOfRange, err := w.fetchRowColVals(txn, handleRange)
 		if err != nil {