Quiz memory problem when anonymus user is taking quiz

Thanks a lot for your support, I would see this should resolve the bug by only loading the one row, but i was suggesting a different alternative which is to keep aside attempts for anonymous users, so in my case i added the below condition to the code (user_is_logged_in) as it makes some common sense for me to say that all anonymous users cannot track their attempts as they are all having the same UID = 0 though they are different persons

Please, let me know what do you think, thanks

    $new = !empty($entity->is_new);

    if ( user_is_logged_in() && !isset($entity->attempt)) {
      $efq = new EntityFieldQuery();
      $result = $efq->entityCondition('entity_type', 'quiz_result')
        ->propertyCondition('nid', $entity->nid)
        ->propertyCondition('uid', $entity->uid)
        ->propertyOrderBy('attempt', 'DESC')
        ->range(0, 1)
        ->execute();
      if (!empty($result['quiz_result'])) {
        $keys = array_keys($result['quiz_result']);
        $existing = quiz_result_load(reset($keys));
        $entity->attempt = $existing->attempt + 1;
      }
    }

Thanks but looks like you forgot to include the range statement which will limit the returned results in case of authenticated users

        ->range(0, 1)

i would assume the below should pass the test cases

     if (!isset($entity->attempt)) {
-      $efq = new EntityFieldQuery();
-      $result = $efq->entityCondition('entity_type', 'quiz_result')
-        ->propertyCondition('nid', $entity->nid)
-        ->propertyCondition('uid', $entity->uid)
-        ->propertyOrderBy('attempt', 'DESC')
-        ->execute();
-      if (!empty($result['quiz_result'])) {
-        $keys = array_keys($result['quiz_result']);
-        $existing = quiz_result_load(reset($keys));
-        $entity->attempt = $existing->attempt + 1;
+      if ($entity->uid == 0) {
+        $entity->attempt = 1;
+      }
+      else {
+        $efq = new EntityFieldQuery();
+        $result = $efq->entityCondition('entity_type', 'quiz_result')
+          ->propertyCondition('nid', $entity->nid)
+          ->propertyCondition('uid', $entity->uid)
+          ->propertyOrderBy('attempt', 'DESC')
+          ->range(0, 1)
+          ->execute();
+        if (!empty($result['quiz_result'])) {
+          $keys = array_keys($result['quiz_result']);
+          $existing = quiz_result_load(reset($keys));
+          $entity->attempt = $existing->attempt + 1;
+        }
       }
     }