fix remove offline nodes in watchDmChannel (#18906)

Signed-off-by: Wei Liu <wei.liu@zilliz.com>

Signed-off-by: Wei Liu <wei.liu@zilliz.com>

internal/querycoord/cluster.go

@@ -305,7 +305,7 @@ func (c *queryNodeCluster) WatchDmChannels(ctx context.Context, nodeID int64, in
 			old, ok := c.clusterMeta.getDmChannel(info.ChannelName)
 			if ok {
 				nodes = append(nodes, old.NodeIds...)
-				removeFromSlice(nodes, in.OfflineNodeID)
+				nodes = removeFromSlice(nodes, in.OfflineNodeID)
 				log.Debug("Remove offline node from dmChannel",
 					zap.String("channel", info.ChannelName),
 					zap.Int64("removedNode", in.OfflineNodeID),

internal/querynode/task.go

@@ -151,6 +151,23 @@ func (w *watchDmChannelsTask) Execute(ctx context.Context) (err error) {
 	// init collection meta
 	coll := w.node.metaReplica.addCollection(collectionID, w.req.Schema)
 
+	loadedChannelCounter := 0
+	for _, toLoadChannel := range vChannels {
+		for _, loadedChannel := range coll.vChannels {
+			if toLoadChannel == loadedChannel {
+				loadedChannelCounter += 1
+				break
+			}
+		}
+	}
+
+	// check if all channels has been loaded, if YES, should do nothing and return
+	// in case of query coord trigger same watchDmChannelTask on multi
+	if len(vChannels) == loadedChannelCounter {
+		log.Warn("All channel has been loaded, skip this watchDmChannelsTask")
+		return nil
+	}
+
 	//add shard cluster
 	for _, vchannel := range vChannels {
 		w.node.ShardClusterService.addShardCluster(w.req.GetCollectionID(), w.req.GetReplicaID(), vchannel)

internal/querynode/task_test.go

@@ -97,6 +97,30 @@ func TestTask_watchDmChannelsTask(t *testing.T) {
 		assert.NoError(t, err)
 	})
 
+	t.Run("test execute repeated watchDmChannelTask", func(t *testing.T) {
+		node, err := genSimpleQueryNode(ctx)
+		assert.NoError(t, err)
+
+		task := watchDmChannelsTask{
+			req:  genWatchDMChannelsRequest(),
+			node: node,
+		}
+
+		task.req.Infos = []*datapb.VchannelInfo{
+			{
+				CollectionID: defaultCollectionID,
+				ChannelName:  defaultDMLChannel,
+			},
+		}
+		task.req.PartitionIDs = []UniqueID{0}
+
+		err = task.Execute(ctx)
+		assert.NoError(t, err)
+		// query coord may submit same watchDmChannelTask
+		err = task.Execute(ctx)
+		assert.NoError(t, err)
+	})
+
 	t.Run("test execute loadPartition", func(t *testing.T) {
 		node, err := genSimpleQueryNode(ctx)
 		assert.NoError(t, err)