diff --git a/internal/types/types.go b/internal/types/types.go
index 9f12ed30e889fd9dc282e812de2c428b201dfb00..28ef3c199966db2a965852854927cf974b5c6c31 100644
--- a/internal/types/types.go
+++ b/internal/types/types.go
@@ -370,6 +370,7 @@ type RootCoord interface {
 	// to build index for this segment.
 	SegmentFlushCompleted(ctx context.Context, in *datapb.SegmentFlushCompletedMsg) (*commonpb.Status, error)
 
+	// GetMetrics notifies RootCoord to collect metrics for specified component
 	GetMetrics(ctx context.Context, req *milvuspb.GetMetricsRequest) (*milvuspb.GetMetricsResponse, error)
 }