/**
  * Starts a query.
  *
  * @param string $queryText
  * @param integer $queryType
  * @return integer|null
  */
 public function queryStart($queryText, $queryType = null)
 {
     $result = parent::queryStart($queryText, $queryType);
     $backtrace = debug_backtrace();
     $trace = array();
     foreach ($backtrace as $rec) {
         if (isset($rec['function'])) {
             $t['call'] = '';
             if (isset($rec['class'])) {
                 $t['call'] .= $rec['class'] . $rec['type'] . $rec['function'];
             } else {
                 $t['call'] .= $rec['function'];
             }
             $t['call'] .= '(';
             if (sizeof($rec['args'])) {
                 foreach ($rec['args'] as $arg) {
                     if (is_object($arg)) {
                         $t['call'] .= get_class($arg);
                     } else {
                         $arg = str_replace("\n", ' ', (string) $arg);
                         $t['call'] .= '"' . (strlen($arg) <= 30 ? $arg : substr($arg, 0, 25) . '[...]') . '"';
                     }
                     $t['call'] .= ', ';
                 }
                 $t['call'] = substr($t['call'], 0, -2);
             }
             $t['call'] .= ")";
         }
         $t['file'] = @$rec['file'] . ':' . @$rec['line'];
         $trace[] = $t;
     }
     $this->getLastQueryProfile()->bindParam('trace', $trace);
     return $result;
 }