diff --git a/README.md b/README.md
index dedc5aa5..a3ebb54b 100644
--- a/README.md
+++ b/README.md
@@ -421,6 +421,7 @@ AS
   SELECT * FROM get_pg_stat_statements();
 
 GRANT SELECT ON postgres_exporter.pg_stat_statements TO postgres_exporter;
+GRANT ALL ON FUNCTION pg_catalog.pg_ls_waldir() TO postgres_exporter;
 ```
 
 > **NOTE**