diff --git a/br/pkg/restore/client.go b/br/pkg/restore/client.go
index f116443840d69..53ba8a88d9d7d 100644
--- a/br/pkg/restore/client.go
+++ b/br/pkg/restore/client.go
@@ -1588,7 +1588,10 @@ func (rc *Client) WaitForFilesRestored(ctx context.Context, files []*backuppb.Fi
 		fileReplica := file
 		rc.workerPool.ApplyOnErrorGroup(eg,
 			func() error {
-				defer updateCh.Inc()
+				defer func() {
+					log.Info("import sst files done", logutil.Files(files))
+					updateCh.Inc()
+				}()
 				return rc.fileImporter.ImportSSTFiles(ectx, []*backuppb.File{fileReplica}, EmptyRewriteRule(), rc.cipher, rc.backupMeta.ApiVersion)
 			})
 	}
diff --git a/br/pkg/restore/import.go b/br/pkg/restore/import.go
index be549ac13c6a0..f0dbb914b122e 100644
--- a/br/pkg/restore/import.go
+++ b/br/pkg/restore/import.go
@@ -485,6 +485,30 @@ func (importer *FileImporter) SetRawRange(startKey, endKey []byte) error {
 	return nil
 }
 
+func getKeyRangeByMode(mode KvMode) func(f *backuppb.File, rules *RewriteRules) ([]byte, []byte, error) {
+	switch mode {
+	case Raw:
+		return func(f *backuppb.File, rules *RewriteRules) ([]byte, []byte, error) {
+			return f.GetStartKey(), f.GetEndKey(), nil
+		}
+	case Txn:
+		return func(f *backuppb.File, rules *RewriteRules) ([]byte, []byte, error) {
+			start, end := f.GetStartKey(), f.GetEndKey()
+			if len(start) != 0 {
+				start = codec.EncodeBytes([]byte{}, f.GetStartKey())
+			}
+			if len(end) != 0 {
+				end = codec.EncodeBytes([]byte{}, f.GetEndKey())
+			}
+			return start, end, nil
+		}
+	default:
+		return func(f *backuppb.File, rules *RewriteRules) ([]byte, []byte, error) {
+			return GetRewriteRawKeys(f, rules)
+		}
+	}
+}
+
 // getKeyRangeForFiles gets the maximum range on files.
 func (importer *FileImporter) getKeyRangeForFiles(
 	files []*backuppb.File,
@@ -495,20 +519,12 @@ func (importer *FileImporter) getKeyRangeForFiles(
 		start, end       []byte
 		err              error
 	)
-
+	getRangeFn := getKeyRangeByMode(importer.kvMode)
 	for _, f := range files {
-		if importer.kvMode == Raw {
-			start, end = f.GetStartKey(), f.GetEndKey()
-		} else if importer.kvMode == Txn {
-			start = codec.EncodeBytes([]byte{}, f.GetStartKey())
-			end = codec.EncodeBytes([]byte{}, f.GetEndKey())
-		} else {
-			start, end, err = GetRewriteRawKeys(f, rewriteRules)
-			if err != nil {
-				return nil, nil, errors.Trace(err)
-			}
+		start, end, err = getRangeFn(f, rewriteRules)
+		if err != nil {
+			return nil, nil, errors.Trace(err)
 		}
-
 		if len(startKey) == 0 || bytes.Compare(start, startKey) < 0 {
 			startKey = start
 		}
diff --git a/br/pkg/restore/util_test.go b/br/pkg/restore/util_test.go
index 4af813e39a4fc..adcaed80a1514 100644
--- a/br/pkg/restore/util_test.go
+++ b/br/pkg/restore/util_test.go
@@ -16,6 +16,65 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestGetKeyRangeByMode(t *testing.T) {
+	file := &backuppb.File{
+		Name:     "file_write.sst",
+		StartKey: []byte("t1a"),
+		EndKey:   []byte("t1ccc"),
+	}
+	endFile := &backuppb.File{
+		Name:     "file_write.sst",
+		StartKey: []byte("t1a"),
+		EndKey:   []byte(""),
+	}
+	rule := &RewriteRules{
+		Data: []*import_sstpb.RewriteRule{
+			{
+				OldKeyPrefix: []byte("t1"),
+				NewKeyPrefix: []byte("t2"),
+			},
+		},
+	}
+	// raw kv
+	testRawFn := getKeyRangeByMode(Raw)
+	start, end, err := testRawFn(file, rule)
+	require.NoError(t, err)
+	require.Equal(t, []byte("t1a"), start)
+	require.Equal(t, []byte("t1ccc"), end)
+
+	start, end, err = testRawFn(endFile, rule)
+	require.NoError(t, err)
+	require.Equal(t, []byte("t1a"), start)
+	require.Equal(t, []byte(""), end)
+
+	// txn kv: the keys must be encoded.
+	testTxnFn := getKeyRangeByMode(Txn)
+	start, end, err = testTxnFn(file, rule)
+	require.NoError(t, err)
+	require.Equal(t, codec.EncodeBytes(nil, []byte("t1a")), start)
+	require.Equal(t, codec.EncodeBytes(nil, []byte("t1ccc")), end)
+
+	start, end, err = testTxnFn(endFile, rule)
+	require.NoError(t, err)
+	require.Equal(t, codec.EncodeBytes(nil, []byte("t1a")), start)
+	require.Equal(t, []byte(""), end)
+
+	// normal kv: the keys must be encoded.
+	testFn := getKeyRangeByMode(TiDB)
+	start, end, err = testFn(file, rule)
+	require.NoError(t, err)
+	require.Equal(t, codec.EncodeBytes(nil, []byte("t2a")), start)
+	require.Equal(t, codec.EncodeBytes(nil, []byte("t2ccc")), end)
+
+	// TODO maybe fix later
+	// current restore does not support rewrite empty endkey.
+	// because backup guarantees that the end key is not empty.
+	// start, end, err = testFn(endFile, rule)
+	// require.NoError(t, err)
+	// require.Equal(t, codec.EncodeBytes(nil, []byte("t2a")), start)
+	// require.Equal(t, []byte(""), end)
+}
+
 func TestParseQuoteName(t *testing.T) {
 	schema, table := ParseQuoteName("`a`.`b`")
 	require.Equal(t, "a", schema)