diff --git a/cdn/rpcserver/rpcserver.go b/cdn/rpcserver/rpcserver.go
index 1e5ff0af4..f0f16d04e 100644
--- a/cdn/rpcserver/rpcserver.go
+++ b/cdn/rpcserver/rpcserver.go
@@ -220,7 +220,9 @@ func (css *Server) GetPieceTasks(ctx context.Context, req *base.PieceTaskRequest
 		}
 	}
 	pieceMd5Sign := seedTask.PieceMd5Sign
+	// TODO The calculation of sign has been completed after the source has been completed. This is just a fallback
 	if len(taskPieces) == int(seedTask.TotalPieceCount) && pieceMd5Sign == "" {
+		logger.WithTaskID(req.TaskId).Warn("The code flow should not go to this point, if the output of this log need to check why")
 		var pieceMd5s []string
 		for i := 0; i < len(taskPieces); i++ {
 			pieceMd5s = append(pieceMd5s, taskPieces[i].PieceMd5)
diff --git a/cdn/supervisor/progress/manager.go b/cdn/supervisor/progress/manager.go
index 51b9a3605..24a97750b 100644
--- a/cdn/supervisor/progress/manager.go
+++ b/cdn/supervisor/progress/manager.go
@@ -21,7 +21,6 @@ package progress
 import (
 	"context"
 	"encoding/json"
-	"sort"
 	"sync"
 
 	"github.com/pkg/errors"
@@ -86,9 +85,6 @@ func (pm *manager) WatchSeedProgress(ctx context.Context, clientAddr string, tas
 				logger.Debugf("subscriber %s starts watching task %s seed progress", clientAddr, taskID)
 				close(pieceChan)
 			}()
-			sort.Slice(pieces, func(i, j int) bool {
-				return pieces[i].PieceNum < pieces[j].PieceNum
-			})
 			for _, piece := range pieces {
 				logger.Debugf("notifies subscriber %s about %d piece info of taskID %s", clientAddr, piece.PieceNum, taskID)
 				pieceChan <- piece
diff --git a/cdn/supervisor/task/manager.go b/cdn/supervisor/task/manager.go
index 506a12a69..153aaba08 100644
--- a/cdn/supervisor/task/manager.go
+++ b/cdn/supervisor/task/manager.go
@@ -19,6 +19,7 @@
 package task
 
 import (
+	"sort"
 	"sync"
 	"time"
 
@@ -54,7 +55,7 @@ type Manager interface {
 	// UpdateProgress update the downloaded pieces belonging to the task
 	UpdateProgress(taskID string, piece *PieceInfo) (err error)
 
-	// GetProgress returns the downloaded pieces belonging to the task
+	// GetProgress returns the downloaded pieces belonging to the task，sorted by pieceNum ascending order
 	GetProgress(taskID string) ([]*PieceInfo, error)
 
 	// Exist check task existence with specified taskID.
@@ -217,6 +218,9 @@ func (tm *manager) GetProgress(taskID string) ([]*PieceInfo, error) {
 		pieces = append(pieces, value.(*PieceInfo))
 		return true
 	})
+	sort.Slice(pieces, func(i, j int) bool {
+		return pieces[i].PieceNum < pieces[j].PieceNum
+	})
 	return pieces, nil
 }