diff --git a/internal/querycoordv2/checkers/leader_checker.go b/internal/querycoordv2/checkers/leader_checker.go
index 0eb0d6dd1b5a6..77fdda14dc859 100644
--- a/internal/querycoordv2/checkers/leader_checker.go
+++ b/internal/querycoordv2/checkers/leader_checker.go
@@ -121,6 +121,11 @@ func (c *LeaderChecker) findNeedSyncPartitionStats(ctx context.Context, replica
 		psVersionInLView := partStatsInLView[partID]
 		if psVersionInLView < psVersionInTarget {
 			partStatsToUpdate[partID] = psVersionInTarget
+		} else {
+			log.RatedDebug(60, "no need to update part stats for partition",
+				zap.Int64("partitionID", partID),
+				zap.Int64("psVersionInLView", psVersionInLView),
+				zap.Int64("psVersionInTarget", psVersionInTarget))
 		}
 	}
 	if len(partStatsToUpdate) > 0 {
@@ -139,6 +144,9 @@ func (c *LeaderChecker) findNeedSyncPartitionStats(ctx context.Context, replica
 		t.SetPriority(task.TaskPriorityLow)
 		t.SetReason("sync partition stats versions")
 		ret = append(ret, t)
+		log.Debug("Created leader actions for partitionStats",
+			zap.Int64("collectionID", leaderView.CollectionID),
+			zap.Any("action", action.String()))
 	}
 
 	return ret
diff --git a/internal/querycoordv2/meta/target_manager.go b/internal/querycoordv2/meta/target_manager.go
index 6d1eb062e4174..f6851f2326511 100644
--- a/internal/querycoordv2/meta/target_manager.go
+++ b/internal/querycoordv2/meta/target_manager.go
@@ -113,18 +113,26 @@ func (mgr *TargetManager) UpdateCollectionCurrentTarget(collectionID int64) bool
 	mgr.current.updateCollectionTarget(collectionID, newTarget)
 	mgr.next.removeCollectionTarget(collectionID)
 
-	log.Debug("finish to update current target for collection",
-		zap.Int64s("segments", newTarget.GetAllSegmentIDs()),
-		zap.Strings("channels", newTarget.GetAllDmChannelNames()),
-		zap.Int64("version", newTarget.GetTargetVersion()),
-	)
+	partStatsVersionInfo := "partitionStats:"
 	for channelName, dmlChannel := range newTarget.dmChannels {
 		ts, _ := tsoutil.ParseTS(dmlChannel.GetSeekPosition().GetTimestamp())
 		metrics.QueryCoordCurrentTargetCheckpointUnixSeconds.WithLabelValues(
 			fmt.Sprint(paramtable.GetNodeID()),
 			channelName,
 		).Set(float64(ts.Unix()))
+		partStatsVersionInfo += fmt.Sprintf("%s:[", channelName)
+		partStatsVersion := dmlChannel.PartitionStatsVersions
+		for partID, statVersion := range partStatsVersion {
+			partStatsVersionInfo += fmt.Sprintf("%d:%d,", partID, statVersion)
+		}
+		partStatsVersionInfo += "],"
 	}
+	log.Debug("finish to update current target for collection",
+		zap.Int64s("segments", newTarget.GetAllSegmentIDs()),
+		zap.Strings("channels", newTarget.GetAllDmChannelNames()),
+		zap.Int64("version", newTarget.GetTargetVersion()),
+		zap.String("partStatsVersion", partStatsVersionInfo),
+	)
 	return true
 }
 
diff --git a/internal/querynodev2/delegator/delegator.go b/internal/querynodev2/delegator/delegator.go
index f0ee9dec318c6..1d11b4c5add68 100644
--- a/internal/querynodev2/delegator/delegator.go
+++ b/internal/querynodev2/delegator/delegator.go
@@ -796,8 +796,14 @@ func (sd *shardDelegator) loadPartitionStats(ctx context.Context, partStatsVersi
 	colID := sd.Collection()
 	log := log.Ctx(ctx)
 	for partID, newVersion := range partStatsVersions {
-		curStats, exist := sd.partitionStats[partID]
-		if exist && curStats.Version >= newVersion {
+		var curStats *storage.PartitionStatsSnapshot
+		var exist bool
+		func() {
+			sd.partitionStatsMut.RLock()
+			defer sd.partitionStatsMut.RUnlock()
+			curStats, exist = sd.partitionStats[partID]
+		}()
+		if exist && curStats != nil && curStats.Version >= newVersion {
 			log.RatedWarn(60, "Input partition stats' version is less or equal than current partition stats, skip",
 				zap.Int64("partID", partID),
 				zap.Int64("curVersion", curStats.Version),