diff --git a/src/mte.ml b/src/mte.ml
index 4c3ca802..8b0428f0 100644
--- a/src/mte.ml
+++ b/src/mte.ml
@@ -91,6 +91,8 @@ let () =
   Caqti_miou.Switch.run @@ fun sw ->
   let db_conn =
     let db_uri = Config.Exchangedb_postgres.config in
+    (* IMPROVE: use caqti pool
+       [connect_pool] with parameter [?post_connect] for preflight *)
     match Caqti_mnet.connect ~sw stack tcp dns db_uri with
     | Error err ->
         Fmt.failwith "Database connection failure: %a." Caqti_error.pp err