diff --git a/README.md b/README.md
index 2e6371f..a6806b1 100644
--- a/README.md
+++ b/README.md
@@ -92,6 +92,8 @@ create_immv(immv_name text, view_definition text) RETURNS bigint
 
 When an IMMV is created, some triggers are automatically created so that the view's contents are immediately updated when its base tables are modified. In addition, a unique index is created on the IMMV automatically if possible.  If the view definition query has a GROUP BY clause, a unique index is created on the columns of GROUP BY expressions. Also, if the view has DISTINCT clause, a unique index is created on all columns in the target list. Otherwise, if the IMMV contains all primary key attributes of its base tables in the target list, a unique index is created on these attributes.  In other cases, no index is created.
 
+Note that if you use PostgreSQL 17 or later, while `create_immv` is running, the `search_path` is temporarily changed to `pg_catalog, pg_temp`.
+
 #### refresh_imm
 
 Use `refresh_immv` function to refresh IMMV.