diff --git a/internal/querycoordv2/balance/score_based_balancer.go b/internal/querycoordv2/balance/score_based_balancer.go
index 874a070fdfc1a..97f65ed08c0f5 100644
--- a/internal/querycoordv2/balance/score_based_balancer.go
+++ b/internal/querycoordv2/balance/score_based_balancer.go
@@ -148,17 +148,22 @@ func (b *ScoreBasedBalancer) convertToNodeItems(collectionID int64, nodeIDs []in
 }
 
 func (b *ScoreBasedBalancer) calculateScore(collectionID, nodeID int64) int {
+	delegatorOverloadFactor := params.Params.QueryCoordCfg.DelegatorMemoryOverloadFactor.GetAsFloat()
+
 	nodeRowCount := 0
+	nodeCollectionRowCount := make(map[int64]int)
 	// calculate global sealed segment row count
 	globalSegments := b.dist.SegmentDistManager.GetByNode(nodeID)
 	for _, s := range globalSegments {
 		nodeRowCount += int(s.GetNumOfRows())
+		nodeCollectionRowCount[s.CollectionID] += int(s.GetNumOfRows())
 	}
 
 	// calculate global growing segment row count
 	views := b.dist.GetLeaderView(nodeID)
 	for _, view := range views {
-		nodeRowCount += int(float64(view.NumOfGrowingRows) * params.Params.QueryCoordCfg.GrowingRowCountWeight.GetAsFloat())
+		nodeRowCount += int(float64(view.NumOfGrowingRows))
+		nodeRowCount += int(float64(nodeCollectionRowCount[view.CollectionID]) * delegatorOverloadFactor)
 	}
 
 	// calculate executing task cost in scheduler
@@ -174,7 +179,8 @@ func (b *ScoreBasedBalancer) calculateScore(collectionID, nodeID int64) int {
 	// calculate collection growing segment row count
 	collectionViews := b.dist.LeaderViewManager.GetByCollectionAndNode(collectionID, nodeID)
 	for _, view := range collectionViews {
-		collectionRowCount += int(float64(view.NumOfGrowingRows) * params.Params.QueryCoordCfg.GrowingRowCountWeight.GetAsFloat())
+		collectionRowCount += int(float64(view.NumOfGrowingRows))
+		collectionRowCount += int(float64(collectionRowCount) * delegatorOverloadFactor)
 	}
 
 	// calculate executing task cost in scheduler
diff --git a/internal/querycoordv2/balance/score_based_balancer_test.go b/internal/querycoordv2/balance/score_based_balancer_test.go
index a1913ee519099..57daa16a1ac30 100644
--- a/internal/querycoordv2/balance/score_based_balancer_test.go
+++ b/internal/querycoordv2/balance/score_based_balancer_test.go
@@ -295,12 +295,23 @@ func (suite *ScoreBasedBalancerTestSuite) TestAssignSegmentWithGrowing() {
 	defer suite.TearDownTest()
 	balancer := suite.balancer
 
+	paramtable.Get().Save(paramtable.Get().QueryCoordCfg.DelegatorMemoryOverloadFactor.Key, "0.3")
+	suite.balancer.meta.PutCollection(&meta.Collection{
+		CollectionLoadInfo: &querypb.CollectionLoadInfo{
+			CollectionID: 1,
+		},
+	}, &meta.Partition{
+		PartitionLoadInfo: &querypb.PartitionLoadInfo{
+			CollectionID: 1,
+			PartitionID:  1,
+		},
+	})
 	distributions := map[int64][]*meta.Segment{
 		1: {
-			{SegmentInfo: &datapb.SegmentInfo{ID: 1, NumOfRows: 20, CollectionID: 1}, Node: 1},
+			{SegmentInfo: &datapb.SegmentInfo{ID: 1, NumOfRows: 100, CollectionID: 1}, Node: 1},
 		},
 		2: {
-			{SegmentInfo: &datapb.SegmentInfo{ID: 2, NumOfRows: 20, CollectionID: 1}, Node: 2},
+			{SegmentInfo: &datapb.SegmentInfo{ID: 2, NumOfRows: 100, CollectionID: 1}, Node: 2},
 		},
 	}
 	for node, s := range distributions {
@@ -321,9 +332,8 @@ func (suite *ScoreBasedBalancerTestSuite) TestAssignSegmentWithGrowing() {
 
 	// mock 50 growing row count in node 1, which is delegator, expect all segment assign to node 2
 	leaderView := &meta.LeaderView{
-		ID:               1,
-		CollectionID:     1,
-		NumOfGrowingRows: 50,
+		ID:           1,
+		CollectionID: 1,
 	}
 	suite.balancer.dist.LeaderViewManager.Update(1, leaderView)
 	plans := balancer.AssignSegment(1, toAssign, lo.Keys(distributions), false)
diff --git a/pkg/util/paramtable/component_param.go b/pkg/util/paramtable/component_param.go
index 708aaf7f8a998..292621cce6c75 100644
--- a/pkg/util/paramtable/component_param.go
+++ b/pkg/util/paramtable/component_param.go
@@ -1384,6 +1384,8 @@ type queryCoordConfig struct {
 	BalanceIntervalSeconds              ParamItem `refreshable:"true"`
 	MemoryUsageMaxDifferencePercentage  ParamItem `refreshable:"true"`
 	GrowingRowCountWeight               ParamItem `refreshable:"true"`
+	DelegatorMemoryOverloadFactor       ParamItem `refreshable:"true`
+	BalanceCostThreshold                ParamItem `refreshable:"true"`
 
 	SegmentCheckInterval       ParamItem `refreshable:"true"`
 	ChannelCheckInterval       ParamItem `refreshable:"true"`
@@ -1555,6 +1557,16 @@ func (p *queryCoordConfig) init(base *BaseTable) {
 	}
 	p.GrowingRowCountWeight.Init(base.mgr)
 
+	p.DelegatorMemoryOverloadFactor = ParamItem{
+		Key:          "queryCoord.delegatorMemoryOverloadFactor",
+		Version:      "2.3.19",
+		DefaultValue: "0.3",
+		PanicIfEmpty: true,
+		Doc:          "the factor of delegator overloaded memory",
+		Export:       true,
+	}
+	p.DelegatorMemoryOverloadFactor.Init(base.mgr)
+
 	p.MemoryUsageMaxDifferencePercentage = ParamItem{
 		Key:          "queryCoord.memoryUsageMaxDifferencePercentage",
 		Version:      "2.0.0",
diff --git a/pkg/util/paramtable/component_param_test.go b/pkg/util/paramtable/component_param_test.go
index 7d6a36089c9c4..54b52b0e01d7e 100644
--- a/pkg/util/paramtable/component_param_test.go
+++ b/pkg/util/paramtable/component_param_test.go
@@ -314,6 +314,8 @@ func TestComponentParam(t *testing.T) {
 		params.Save("queryCoord.checkExecutedFlagInterval", "200")
 		assert.Equal(t, 200, Params.CheckExecutedFlagInterval.GetAsInt())
 		params.Reset("queryCoord.checkExecutedFlagInterval")
+
+		assert.Equal(t, 0.3, Params.DelegatorMemoryOverloadFactor.GetAsFloat())
 	})
 
 	t.Run("test queryNodeConfig", func(t *testing.T) {