Index: modules/system/system.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.install,v
retrieving revision 1.347
diff -u -p -r1.347 system.install
--- modules/system/system.install	22 Jun 2009 13:21:37 -0000	1.347
+++ modules/system/system.install	27 Jun 2009 07:10:50 -0000
@@ -352,6 +352,11 @@ function system_install() {
     drupal_install_schema($module);
   }
 
+  // Alter postgresql sequence to skip built-in roles.
+  if (db_driver() == 'pgsql') {
+    db_query('ALTER SEQUENCE {role}_rid_seq RESTART WITH 3');
+  }
+
   // Load system theme data appropriately.
   system_get_theme_data();