Index: acl.install
===================================================================
--- acl.install	(revision 105)
+++ acl.install	(working copy)
@@ -157,5 +157,6 @@
   // (Dropping and recreating the primary key on an auto_increment column would cause a MySQL failure.)
   db_change_field($ret, 'acl', 'module', 'module', array('type' => 'varchar', 'length' => 255, 'not null' => TRUE));
   db_change_field($ret, 'acl', 'name', 'name', array('type' => 'varchar', 'length' => 255));
+  db_add_index($ret, 'acl_node', 'nid', array('nid'));
   return $ret;
 }