enhance: [2.5] skip adding stopping node to resource group in handleNodeUp (#45969) (#45982)

Cherry-pick from master
pr: #45969
Related to #45960
Follow-up to #45961

After #45961 ensured that handleNodeUp is always called for nodes
discovered during rewatchNodes (including stopping nodes), this change
adds a safeguard in ResourceManager.handleNodeUp to skip adding stopping
nodes to resource groups.

1. **resource_manager.go**: Add check for IsStoppingState() in
handleNodeUp to prevent stopping nodes from being added to incomingNode
set and assigned to resource groups.

2. **server.go**:
- Delete processed nodes from sessionMap to avoid duplicate processing
in the subsequent loop
   - Add warning logs for stopping state transitions during rewatch

Signed-off-by: Congqi Xia <[email protected]>

Author: congqixia

internal/querycoordv2/meta/resource_manager.go

@@ -469,7 +469,12 @@ func (rm *ResourceManager) HandleNodeUp(ctx context.Context, node int64) {
 }
 
 func (rm *ResourceManager) handleNodeUp(ctx context.Context, node int64) {
-	if nodeInfo := rm.nodeMgr.Get(node); nodeInfo == nil || nodeInfo.IsEmbeddedQueryNodeInStreamingNode() {
+	nodeInfo := rm.nodeMgr.Get(node)
+	if nodeInfo == nil || nodeInfo.IsEmbeddedQueryNodeInStreamingNode() {
+		return
+	}
+	if nodeInfo.IsStoppingState() {
+		log.Warn("node is stopping, skip handle node up in resource manager", zap.Int64("node", node))
 		return
 	}
 	rm.incomingNode.Insert(node)

internal/querycoordv2/server.go

@@ -799,10 +799,14 @@ func (s *Server) rewatchNodes(sessions map[string]*sessionutil.Session) error {
 			// node in node manager but session not exist, means it's offline
 			s.nodeMgr.Remove(node.ID())
 			s.handleNodeDown(node.ID())
-		} else if nodeSession.Stopping && !node.IsStoppingState() {
-			// node in node manager but session is stopping, means it's stopping
-			s.nodeMgr.Stopping(node.ID())
-			s.handleNodeStopping(node.ID())
+		} else {
+			if nodeSession.Stopping && !node.IsStoppingState() {
+				// node in node manager but session is stopping, means it's stopping
+				log.Warn("rewatch found old querynode in stopping state", zap.Int64("nodeID", nodeSession.ServerID))
+				s.nodeMgr.Stopping(node.ID())
+				s.handleNodeStopping(node.ID())
+			}
+			delete(sessionMap, node.ID())
 		}
 	}
 
@@ -823,6 +827,7 @@ func (s *Server) rewatchNodes(sessions map[string]*sessionutil.Session) error {
 			s.handleNodeUp(nodeSession.GetServerID())
 
 			if nodeSession.Stopping {
+				log.Warn("rewatch found new querynode in stopping state", zap.Int64("nodeID", nodeSession.ServerID))
 				s.nodeMgr.Stopping(nodeSession.ServerID)
 				s.handleNodeStopping(nodeSession.ServerID)
 			}