fix: Fix index memory estimation (#35225)

issue: #35229

Signed-off-by: sunby <[email protected]>

internal/querynodev2/segments/segment_loader.go

@@ -1196,6 +1196,7 @@ func (loader *segmentLoader) checkSegmentSize(ctx context.Context, segmentLoadIn
 // getResourceUsageEstimateOfSegment estimates the resource usage of the segment
 func getResourceUsageEstimateOfSegment(schema *schemapb.CollectionSchema, loadInfo *querypb.SegmentLoadInfo, multiplyFactor resourceEstimateFactor) (usage *ResourceUsage, err error) {
 	var segmentMemorySize, segmentDiskSize uint64
+	var indexMemorySize uint64
 	var mmapFieldCount int
 
 	vecFieldID2IndexInfo := make(map[int64]*querypb.FieldIndexInfo)
@@ -1216,7 +1217,7 @@ func getResourceUsageEstimateOfSegment(schema *schemapb.CollectionSchema, loadIn
 					loadInfo.GetSegmentID(),
 					fieldIndexInfo.GetBuildID())
 			}
-			segmentMemorySize += neededMemSize
+			indexMemorySize += neededMemSize
 			if mmapEnabled {
 				segmentDiskSize += neededMemSize + neededDiskSize
 			} else {
@@ -1253,7 +1254,7 @@ func getResourceUsageEstimateOfSegment(schema *schemapb.CollectionSchema, loadIn
 		segmentMemorySize += uint64(float64(getBinlogDataMemorySize(fieldBinlog)) * multiplyFactor.deltaDataExpansionFactor)
 	}
 	return &ResourceUsage{
-		MemorySize:     segmentMemorySize,
+		MemorySize:     segmentMemorySize + indexMemorySize,
 		DiskSize:       segmentDiskSize,
 		MmapFieldCount: mmapFieldCount,
 	}, nil