Index: modules/field/field.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.install,v
retrieving revision 1.9
diff -u -r1.9 field.install
--- modules/field/field.install	28 May 2009 10:05:32 -0000	1.9
+++ modules/field/field.install	9 Aug 2009 20:32:57 -0000
@@ -129,10 +129,9 @@
       ),
     ),
     'primary key' => array('id'),
-    'unique keys' => array(
-      'field_id_bundle' => array('field_id', 'bundle'),
-    ),
     'indexes' => array(
+      // used by field_delete_instance().
+      'field_name_bundle' => array('field_name', 'bundle'),
       // used by field_read_instances()
       'widget_active_deleted' => array('widget_active', 'deleted'),
       // used by field_modules_disabled()