diff --git a/docs-2.0/8.service-tuning/2.graph-modeling.md b/docs-2.0/8.service-tuning/2.graph-modeling.md
index 513657bfa83..61bc1ff5e8b 100644
--- a/docs-2.0/8.service-tuning/2.graph-modeling.md
+++ b/docs-2.0/8.service-tuning/2.graph-modeling.md
@@ -14,6 +14,10 @@ There is no perfect method to model in Nebula Graph. Graph modeling depends on
 
 Usually, various types of queries are validated in test scenarios to assess the overall capabilities of the system. However, in most production scenarios, there are not many types of frequently used queries. You can optimize the data model based on key queries selected according to the Pareto (80/20) principle.
 
+### Full-graph scanning avoidance
+
+Graph traversal can be performed after one or more vertices/edges are located through property indexes or VIDs. But for some query patterns, such as subgraph and path query patterns, the source vertex or edge of the traversal cannot be located through property indexes or VIDs. These queries find all the subgraphs that satisfy the query pattern by scanning the whole graph space which will have poor query performance. Nebula Graph does not implement indexing for the graph structures of subgraphs or paths. 
+
 ### No predefined bonds between Tags and Edge types
 
 Define the bonds between Tags and Edge types in the application, not Nebula Graph. There are no statements that could get the bonds between Tags and Edge types.