diff --git a/src/plugins/server/data.ml b/src/plugins/server/data.ml
index 0dc576f61ca97541dd4e906cac794a5827f24732..1f20d6d4c36fb901dfa0745f3250418c76edc568 100644
--- a/src/plugins/server/data.ml
+++ b/src/plugins/server/data.ml
@@ -635,8 +635,8 @@ struct
   let get m a =
     try M.find a m.index
     with Not_found ->
-      let id = m.kid in
-      m.kid <- succ id ;
+      let id = succ m.kid in
+      m.kid <- id ;
       m.index <- M.add a id m.index ;
       Hashtbl.add m.lookup id a ; id