mixed _cache( array $callPath, array $parameters [, int $timeout=3600] )
$data['result'] = $this->erp_test_model->get_price_change_history($param1, $param2 );
$data['result'] = _cache( array($this,"erp_test_model", "get_price_change_history") , array($param1, $param2) );
$data['result'] = _cache( array($this,"erp_test_model", "get_price_change_history") , array($param1, $param2) , 30*60 // timeout을 30분으로 조정 );
$query->close_result(); $query->next_result(); $query->next_result_array();