columns type 

Added to use created, updated, modified in mapping definition

  public $_mapping = array(
                'id' => array('type' => 'string', 'index' => 'not_analyzed', 'length' => 36),
                'client_id' => array('type' => 'integer'),
                'name' => array('type' => 'string', 'include_in_all' => false),
                'lastname' => array('type' => 'string', 'include_in_all' => false),
                'email' => array('type' => 'string'),
                'history' => array(
                    'type'=> 'object',
                    'properties' => array(
                        'field' => array('type' => 'string', 'index' => 'not_analyzed'),
                        'new_value' => array('type' => 'string', 'index' => 'not_analyzed'),
                        'old_value' => array('type' => 'string', 'index' => 'not_analyzed').
                    )
                ),
                'created' => array('type' => 'datetime', 'format' => 'yyyy-MM-dd HH:mm:ss'),
                'modified' => array('type' => 'datetime', 'format' => 'yyyy-MM-dd HH:mm:ss')
    );