Index: includes/update.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/update.inc,v
retrieving revision 1.2
diff -u -p -r1.2 update.inc
--- includes/update.inc	3 Aug 2009 19:37:38 -0000	1.2
+++ includes/update.inc	18 Aug 2009 04:01:56 -0000
@@ -308,9 +308,28 @@ function update_do_one($module, $number,
     return;
   }
 
+  if (!isset($context['update_log_queries'])) {
+    $context['log'] = (bool) variable_get('update_log_queries', FALSE);
+  }
+
+  $ret = array();
   $function = $module . '_update_' . $number;
   if (function_exists($function)) {
-    $ret = $function($context['sandbox']);
+    try {
+      if ($context['log']) {
+        Database::startLog($function);
+      }
+      $ret = $function($context['sandbox']);
+    }
+    catch (DrupalUpdateException $e) {
+      $ret['#abort'] = array('success' => FALSE, 'query' => $e->getMessage());
+    }
+    catch (Exception $e) {
+      $ret['#abort'] = array('success' => FALSE, 'query' => $e->getMessage());
+    }
+    if ($context['log']) {
+      $ret['queries'] = Database::getLog($function);
+    }
   }
 
   if (isset($ret['#finished'])) {
@@ -338,6 +357,12 @@ function update_do_one($module, $number,
 }
 
 /**
+ * @class Exception class used to throw error if a module update fails.
+ */
+class DrupalUpdateException extends Exception {
+}
+
+/**
  * Start the database update batch process.
  *
  * @param $start