<?php

private function mapping($q, $result)
    {
        $types = [];
        for ($i = 0, $count = \pg_num_fields($q); $i < $count; ++$i) {
            $types[$i] = \pg_field_type_oid($q, $i);
        }
        foreach ($result as $k => &$row) {
            $i = -1;
            foreach ($row as $name => &$value) {
                ++$i;
                if ($value === null) {
                    continue;
                }
                switch ($types[$i]) {
                    case 20:
                    case 21:
                    case 23: $value = (int)$value; break;
                    case 16507: /*$value = (string)$value; */break;
                    default:
                        throw new \RuntimeException(
                            \pg_field_type($q, $i) .' type. Need mapping ' . \pg_field_type_oid($q, $i)
                        );
                }
            }
        }
        unset($value, $row);

        return $result;
    }

?>

This function can be used to improve the performance of your application. 
pg_field_type() makes an internal query to the pg_type table and it can be really slow. 
So if your application previously know the oids of your database, you can save the execution time of this query in every request.