Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1176
diff -u -r1.1176 common.inc
--- includes/common.inc	9 Jun 2010 14:55:30 -0000	1.1176
+++ includes/common.inc	16 Jun 2010 10:44:58 -0000
@@ -5896,6 +5896,12 @@
       $serial = $field;
     }
 
+    // Skip field if it is an update key as it is unnecessary to update a
+    // column to the value it is already set to.
+    if (in_array($field, $primary_keys)) {
+      continue;
+    }
+
     if (!property_exists($object, $field)) {
       // Skip fields that are not provided, unless we are inserting and a
       // default value is provided by the schema.
Index: includes/path.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/path.inc,v
retrieving revision 1.63
diff -u -r1.63 path.inc
--- includes/path.inc	18 May 2010 18:26:30 -0000	1.63
+++ includes/path.inc	16 Jun 2010 10:44:58 -0000
@@ -393,7 +393,7 @@
   $path += array('pid' => NULL, 'language' => LANGUAGE_NONE);
 
   // Insert or update the alias.
-  $status = drupal_write_record('url_alias', $path, (!empty($path['pid']) ? 'pid' : NULL));
+  $status = drupal_write_record('url_alias', $path, (!empty($path['pid']) ? 'pid' : array()));
 
   // Verify that a record was written.
   if (isset($status) && $status) {