diff --git a/internal/distributed/datacoord/service.go b/internal/distributed/datacoord/service.go
index 11a67188b6..b58448c38b 100644
--- a/internal/distributed/datacoord/service.go
+++ b/internal/distributed/datacoord/service.go
@@ -199,6 +199,7 @@ func (s *Server) Flush(ctx context.Context, req *datapb.FlushRequest) (*datapb.F
 	return s.dataCoord.Flush(ctx, req)
 }
 
+// AssignSegmentID requests to allocate segment space for insert
 func (s *Server) AssignSegmentID(ctx context.Context, req *datapb.AssignSegmentIDRequest) (*datapb.AssignSegmentIDResponse, error) {
 	return s.dataCoord.AssignSegmentID(ctx, req)
 }