Fix GetShardLeader returns old leader (#22887)

Signed-off-by: yah01 <yang.cen@zilliz.com>

internal/querycoordv2/dist/dist_handler.go

@@ -195,10 +195,19 @@ func (dh *distHandler) updateLeaderView(resp *querypb.GetDataDistributionRespons
 			}
 		}
 
+		var version int64
+		for _, channel := range resp.GetChannels() {
+			if channel.GetChannel() == lview.GetChannel() {
+				version = channel.GetVersion()
+				break
+			}
+		}
+
 		view := &meta.LeaderView{
 			ID:              resp.GetNodeID(),
 			CollectionID:    lview.GetCollection(),
 			Channel:         lview.GetChannel(),
+			Version:         version,
 			Segments:        lview.GetSegmentDist(),
 			GrowingSegments: segments,
 		}

internal/querycoordv2/handlers.go

@@ -374,3 +374,31 @@ func checkNodeAvailable(nodeID int64, info *session.NodeInfo) error {
 	}
 	return nil
 }
+
+func filterDupLeaders(replicaManager *meta.ReplicaManager, leaders map[int64]*meta.LeaderView) map[int64]*meta.LeaderView {
+	type leaderID struct {
+		ReplicaID int64
+		Shard     string
+	}
+
+	newLeaders := make(map[leaderID]*meta.LeaderView)
+	for _, view := range leaders {
+		replica := replicaManager.GetByCollectionAndNode(view.CollectionID, view.ID)
+		if replica == nil {
+			continue
+		}
+
+		id := leaderID{replica.GetID(), view.Channel}
+		if old, ok := newLeaders[id]; ok && old.Version > view.Version {
+			continue
+		}
+
+		newLeaders[id] = view
+	}
+
+	result := make(map[int64]*meta.LeaderView)
+	for _, v := range newLeaders {
+		result[v.ID] = v
+	}
+	return result
+}

internal/querycoordv2/meta/leader_view_manager.go

@@ -27,6 +27,7 @@ type LeaderView struct {
 	ID              int64
 	CollectionID    int64
 	Channel         string
+	Version         int64
 	Segments        map[int64]*querypb.SegmentDist
 	GrowingSegments map[int64]*Segment
 }
@@ -46,6 +47,7 @@ func (view *LeaderView) Clone() *LeaderView {
 		ID:              view.ID,
 		CollectionID:    view.CollectionID,
 		Channel:         view.Channel,
+		Version:         view.Version,
 		Segments:        segments,
 		GrowingSegments: growings,
 	}

internal/querycoordv2/services.go

@@ -859,6 +859,7 @@ func (s *Server) GetShardLeaders(ctx context.Context, req *querypb.GetShardLeade
 		log := log.With(zap.String("channel", channel.GetChannelName()))
 
 		leaders := s.dist.LeaderViewManager.GetLeadersByShard(channel.GetChannelName())
+		leaders = filterDupLeaders(s.meta.ReplicaManager, leaders)
 		ids := make([]int64, 0, len(leaders))
 		addrs := make([]string, 0, len(leaders))