diff --git a/docs/developer_guides/chap03_index_service.md b/docs/developer_guides/chap03_index_service.md
index 74c32058af..c74e5916e6 100644
--- a/docs/developer_guides/chap03_index_service.md
+++ b/docs/developer_guides/chap03_index_service.md
@@ -12,15 +12,14 @@
 
 ```go
 type IndexCoord interface {
-	Component
+  Component
 	TimeTickProvider
 
-	RegisterNode(ctx context.Context, req *indexpb.RegisterNodeRequest) (*indexpb.RegisterNodeResponse, error)
 	BuildIndex(ctx context.Context, req *indexpb.BuildIndexRequest) (*indexpb.BuildIndexResponse, error)
 	DropIndex(ctx context.Context, req *indexpb.DropIndexRequest) (*commonpb.Status, error)
-	GetIndexStates(ctx context.Context, req *indexpb.IndexStatesRequest) (*indexpb.IndexStatesResponse, error)
-	GetIndexFilePaths(ctx context.Context, req *indexpb.IndexFilePathsRequest) (*indexpb.IndexFilePathsResponse, error)
-	NotifyBuildIndex(ctx context.Context, nty *indexpb.BuildIndexNotification) (*commonpb.Status, error)
+	GetIndexStates(ctx context.Context, req *indexpb.GetIndexStatesRequest) (*indexpb.GetIndexStatesResponse, error)
+	GetIndexFilePaths(ctx context.Context, req *indexpb.GetIndexFilePathsRequest) (*indexpb.GetIndexFilePathsResponse, error)
+	GetMetrics(ctx context.Context, req *milvuspb.GetMetricsRequest) (*milvuspb.GetMetricsResponse, error)
 }
 ```