diff --git a/cookbook/configuration/pdo_session_storage.rst b/cookbook/configuration/pdo_session_storage.rst
index be5e606d2ef..7455f705e2a 100644
--- a/cookbook/configuration/pdo_session_storage.rst
+++ b/cookbook/configuration/pdo_session_storage.rst
@@ -30,6 +30,7 @@ configuration format of your choice):
                 db_id_col:   session_id
                 db_data_col: session_value
                 db_time_col: session_time
+                db_lifetime_col: session_lifetime
 
         services:
             pdo: