fix: Prevent leader checker from generating excessive duplicate leader tasks

internal/querycoordv2/checkers/leader_checker.go

@@ -171,13 +171,16 @@ func (c *LeaderChecker) findNeedLoadedSegments(ctx context.Context, replica *met
 			continue
 		}
 
-		// when segment's version in leader view doesn't match segment's version in dist
-		// which means leader view store wrong segment location in leader view, then we should update segment location and segment's version
+		// The routing table on the delegator points to the nodes where segments are loaded. There are two scenarios that require updating the routing table on the delegator:
+		// 1. Missing Segment Routing - The routing table lacks the route for a specific segment.
+		// 2. Outdated Segment Routing - A segment has multiple copies loaded, but the routing table points to a node that does not host the most recently loaded copy.
+		// This ensures the routing table remains accurate and up-to-date, reflecting the latest segment distribution.
 		version, ok := leaderView.Segments[s.GetID()]
-		if !ok || version.GetVersion() != s.Version {
+		if !ok || version.GetNodeID() != s.Node {
 			log.RatedDebug(10, "leader checker append a segment to set",
 				zap.Int64("segmentID", s.GetID()),
 				zap.Int64("nodeID", s.Node))
+
 			action := task.NewLeaderAction(leaderView.ID, s.Node, task.ActionTypeGrow, s.GetInsertChannel(), s.GetID(), time.Now().UnixNano())
 			t := task.NewLeaderSegmentTask(
 				ctx,

internal/querycoordv2/checkers/leader_checker_test.go

@@ -138,22 +138,28 @@ func (suite *LeaderCheckerTestSuite) TestSyncLoadedSegments() {
 	suite.Equal(tasks[0].Actions()[0].(*task.LeaderAction).SegmentID(), int64(1))
 	suite.Equal(tasks[0].Priority(), task.TaskPriorityLow)
 
-	// test segment's version in leader view doesn't match segment's version in dist
-	observer.dist.SegmentDistManager.Update(1, utils.CreateTestSegment(1, 1, 1, 2, 1, "test-insert-channel"))
-	view = utils.CreateTestLeaderView(2, 1, "test-insert-channel", map[int64]int64{}, map[int64]*meta.Segment{})
+	// Verify that the segment routing table in the leader view does not point to the most recent segment replica.
+	// the leader view points to the segment on querynode-2, with version 1
+	// the distribution shows that the segment is on querynode-1, with latest version 2
+	node1, node2 := int64(1), int64(2)
+	version1, version2 := int64(1), int64(2)
+	observer.dist.SegmentDistManager.Update(node1)
+	observer.dist.SegmentDistManager.Update(node2, utils.CreateTestSegment(1, 1, 1, node2, version2, "test-insert-channel"))
+	view = utils.CreateTestLeaderView(node2, 1, "test-insert-channel", map[int64]int64{}, map[int64]*meta.Segment{})
 	view.TargetVersion = observer.target.GetCollectionTargetVersion(ctx, 1, meta.CurrentTarget)
 	view.Segments[1] = &querypb.SegmentDist{
-		NodeID:  0,
-		Version: time.Now().UnixMilli() - 1,
+		NodeID:  node1,
+		Version: version1,
 	}
-	observer.dist.LeaderViewManager.Update(2, view)
+	observer.dist.LeaderViewManager.Update(node2, view)
 
 	tasks = suite.checker.Check(context.TODO())
 	suite.Len(tasks, 1)
 	suite.Equal(tasks[0].Source(), utils.LeaderChecker)
 	suite.Len(tasks[0].Actions(), 1)
 	suite.Equal(tasks[0].Actions()[0].Type(), task.ActionTypeGrow)
-	suite.Equal(tasks[0].Actions()[0].Node(), int64(1))
+	suite.Equal(tasks[0].Actions()[0].Node(), node2)
+	suite.Equal(tasks[0].Actions()[0].(*task.LeaderAction).GetLeaderID(), node2)
 	suite.Equal(tasks[0].Actions()[0].(*task.LeaderAction).SegmentID(), int64(1))
 	suite.Equal(tasks[0].Priority(), task.TaskPriorityLow)