diff --git a/internal/datanode/index/task_stats.go b/internal/datanode/index/task_stats.go
index fc28d2915a..2f56290dd0 100644
--- a/internal/datanode/index/task_stats.go
+++ b/internal/datanode/index/task_stats.go
@@ -592,26 +592,31 @@ func (st *statsTask) createJSONKeyStats(ctx context.Context,
 		}
 		buildIndexParams := buildIndexParams(req, files, field, newStorageConfig, options)
 
-		uploaded, err := indexcgowrapper.CreateJSONKeyStats(ctx, buildIndexParams)
+		statsResult, err := indexcgowrapper.CreateJSONKeyStats(ctx, buildIndexParams)
 		if err != nil {
 			return err
 		}
-		memorySize := int64(0)
-		for _, file := range uploaded {
-			memorySize += file
+
+		// calculate log size (disk size) from file sizes
+		var logSize int64
+		for _, fileSize := range statsResult.Files {
+			logSize += fileSize
 		}
 
 		jsonKeyIndexStats[field.GetFieldID()] = &datapb.JsonKeyStats{
 			FieldID:                field.GetFieldID(),
 			Version:                version,
 			BuildID:                taskID,
-			Files:                  lo.Keys(uploaded),
+			Files:                  lo.Keys(statsResult.Files),
 			JsonKeyStatsDataFormat: jsonKeyStatsDataFormat,
-			MemorySize:             memorySize,
+			MemorySize:             statsResult.MemSize,
+			LogSize:                logSize,
 		}
 		log.Info("field enable json key index, create json key index done",
 			zap.Int64("field id", field.GetFieldID()),
-			zap.Strings("files", lo.Keys(uploaded)),
+			zap.Strings("files", lo.Keys(statsResult.Files)),
+			zap.Int64("memorySize", statsResult.MemSize),
+			zap.Int64("logSize", logSize),
 		)
 	}
 
diff --git a/internal/querynodev2/segments/segment_loader.go b/internal/querynodev2/segments/segment_loader.go
index 675075f583..0c3b64d25f 100644
--- a/internal/querynodev2/segments/segment_loader.go
+++ b/internal/querynodev2/segments/segment_loader.go
@@ -155,6 +155,7 @@ type resourceEstimateFactor struct {
 	EnableInterminSegmentIndex      bool
 	tempSegmentIndexFactor          float64
 	deltaDataExpansionFactor        float64
+	jsonKeyStatsExpansionFactor     float64
 	TieredEvictionEnabled           bool
 	TieredEvictableMemoryCacheRatio float64
 	TieredEvictableDiskCacheRatio   float64
@@ -1610,12 +1611,13 @@ func (loader *segmentLoader) checkSegmentSize(ctx context.Context, segmentLoadIn
 	diskUsage := uint64(localDiskUsage) + loader.committedResource.DiskSize
 
 	maxFactor := resourceEstimateFactor{
-		memoryUsageFactor:          paramtable.Get().QueryNodeCfg.LoadMemoryUsageFactor.GetAsFloat(),
-		memoryIndexUsageFactor:     paramtable.Get().QueryNodeCfg.MemoryIndexLoadPredictMemoryUsageFactor.GetAsFloat(),
-		EnableInterminSegmentIndex: paramtable.Get().QueryNodeCfg.EnableInterminSegmentIndex.GetAsBool(),
-		tempSegmentIndexFactor:     paramtable.Get().QueryNodeCfg.InterimIndexMemExpandRate.GetAsFloat(),
-		deltaDataExpansionFactor:   paramtable.Get().QueryNodeCfg.DeltaDataExpansionRate.GetAsFloat(),
-		TieredEvictionEnabled:      paramtable.Get().QueryNodeCfg.TieredEvictionEnabled.GetAsBool(),
+		memoryUsageFactor:           paramtable.Get().QueryNodeCfg.LoadMemoryUsageFactor.GetAsFloat(),
+		memoryIndexUsageFactor:      paramtable.Get().QueryNodeCfg.MemoryIndexLoadPredictMemoryUsageFactor.GetAsFloat(),
+		EnableInterminSegmentIndex:  paramtable.Get().QueryNodeCfg.EnableInterminSegmentIndex.GetAsBool(),
+		tempSegmentIndexFactor:      paramtable.Get().QueryNodeCfg.InterimIndexMemExpandRate.GetAsFloat(),
+		deltaDataExpansionFactor:    paramtable.Get().QueryNodeCfg.DeltaDataExpansionRate.GetAsFloat(),
+		jsonKeyStatsExpansionFactor: paramtable.Get().QueryNodeCfg.JSONKeyStatsExpansionFactor.GetAsFloat(),
+		TieredEvictionEnabled:       paramtable.Get().QueryNodeCfg.TieredEvictionEnabled.GetAsBool(),
 	}
 	maxSegmentSize := uint64(0)
 	predictMemUsage := memUsage
@@ -2094,6 +2096,21 @@ func estimateLoadingResourceUsageOfSegment(schema *schemapb.CollectionSchema, lo
 		segMemoryLoadingSize += uint64(float64(memSize) * expansionFactor)
 	}
 
+	// PART 5: calculate size of json key stats data
+	jsonStatsMmapEnable := paramtable.Get().QueryNodeCfg.MmapJSONStats.GetAsBool()
+	needWarmup := paramtable.Get().QueryNodeCfg.TieredWarmupScalarIndex.GetValue() == "sync"
+	for _, jsonKeyStats := range loadInfo.GetJsonKeyStatsLogs() {
+		if jsonStatsMmapEnable {
+			if !multiplyFactor.TieredEvictionEnabled || needWarmup {
+				segDiskLoadingSize += uint64(float64(jsonKeyStats.GetMemorySize()) * multiplyFactor.jsonKeyStatsExpansionFactor)
+			}
+		} else {
+			if !multiplyFactor.TieredEvictionEnabled || needWarmup {
+				segMemoryLoadingSize += uint64(float64(jsonKeyStats.GetMemorySize()) * multiplyFactor.jsonKeyStatsExpansionFactor)
+			}
+		}
+	}
+
 	return &ResourceUsage{
 		MemorySize:         segMemoryLoadingSize + indexMemorySize,
 		DiskSize:           segDiskLoadingSize,
diff --git a/internal/util/indexcgowrapper/index.go b/internal/util/indexcgowrapper/index.go
index 304c0c5770..03da27b346 100644
--- a/internal/util/indexcgowrapper/index.go
+++ b/internal/util/indexcgowrapper/index.go
@@ -156,7 +156,14 @@ func CreateTextIndex(ctx context.Context, buildIndexInfo *indexcgopb.BuildIndexI
 	return res, nil
 }
 
-func CreateJSONKeyStats(ctx context.Context, buildIndexInfo *indexcgopb.BuildIndexInfo) (map[string]int64, error) {
+type JSONKeyStatsResult struct {
+	// MemSize is the actual memory size when loaded
+	MemSize int64
+	// Files maps file name to file size on disk
+	Files map[string]int64
+}
+
+func CreateJSONKeyStats(ctx context.Context, buildIndexInfo *indexcgopb.BuildIndexInfo) (*JSONKeyStatsResult, error) {
 	buildIndexInfoBlob, err := proto.Marshal(buildIndexInfo)
 	if err != nil {
 		log.Ctx(ctx).Warn("marshal buildIndexInfo failed",
@@ -177,12 +184,17 @@ func CreateJSONKeyStats(ctx context.Context, buildIndexInfo *indexcgopb.BuildInd
 		return nil, err
 	}
 
-	res := make(map[string]int64)
+	files := make(map[string]int64)
+	var logSize int64
 	for _, indexInfo := range indexStats.GetSerializedIndexInfos() {
-		res[indexInfo.FileName] = indexInfo.FileSize
+		files[indexInfo.FileName] = indexInfo.FileSize
+		logSize += indexInfo.FileSize
 	}
 
-	return res, nil
+	return &JSONKeyStatsResult{
+		MemSize: indexStats.GetMemSize(),
+		Files:   files,
+	}, nil
 }
 
 // TODO: this seems to be used only for test. We should mark the method
diff --git a/pkg/util/paramtable/component_param.go b/pkg/util/paramtable/component_param.go
index ec9cbbdade..29fe4aa88f 100644
--- a/pkg/util/paramtable/component_param.go
+++ b/pkg/util/paramtable/component_param.go
@@ -3244,9 +3244,10 @@ type queryNodeConfig struct {
 	ForwardBatchSize            ParamItem `refreshable:"true"`
 
 	// loader
-	IoPoolSize             ParamItem `refreshable:"false"`
-	DeltaDataExpansionRate ParamItem `refreshable:"true"`
-	DiskSizeFetchInterval  ParamItem `refreshable:"false"`
+	IoPoolSize                  ParamItem `refreshable:"false"`
+	DeltaDataExpansionRate      ParamItem `refreshable:"true"`
+	JSONKeyStatsExpansionFactor ParamItem `refreshable:"true"`
+	DiskSizeFetchInterval       ParamItem `refreshable:"false"`
 
 	// schedule task policy.
 	SchedulePolicyName                    ParamItem `refreshable:"false"`
@@ -4245,6 +4246,14 @@ Max read concurrency must greater than or equal to 1, and less than or equal to
 	}
 	p.DeltaDataExpansionRate.Init(base.mgr)
 
+	p.JSONKeyStatsExpansionFactor = ParamItem{
+		Key:          "querynode.JSONKeyStatsExpansionFactor",
+		Version:      "2.6.7",
+		DefaultValue: "1.0",
+		Doc:          "the expansion factor for json key stats memory size estimation",
+	}
+	p.JSONKeyStatsExpansionFactor.Init(base.mgr)
+
 	p.DiskSizeFetchInterval = ParamItem{
 		Key:          "querynode.diskSizeFetchInterval",
 		Version:      "2.5.0",