diff --git a/Notes b/Notes
index fe05999..3cb3ba9 100644
--- a/Notes
+++ b/Notes
@@ -136,3 +136,9 @@ where file_type = 'f' and checksum is null
   and instances.session=sessions.id
 limit 100000;
 
+remove_session:
+
+select v.id from instances i right outer join versions2 v  on
+i.version=v.id where i.id is null
+is very slow. Do two independent queries and difference via judy?
+In any case all the cleanup stuff needs to be outside of the loop.