BUG #15459: no connection to the server

The following bug has been logged on the website:

Bug reference: 15459
Logged by: medivhJay
Email address: jay(dot)medivh(at)gmail(dot)com
PostgreSQL version: 9.6.8
Operating system: debian
Description:

Hello

I used php7.1 + PDO connect to postgresql

when I use fork , like this

<?php
$pid = pcntl_fork();
if ( $pid === 1 ) {
TaskManager::log('error');
} elseif ( $pid ) {
pcntl_wait($status);
} else {
try {
call_user_func_array($func, $argv);
} catch ( \Exception $e ) {
TaskManager::log($e);
}
exit(0);
}

PDO throw an exception

like this
[2018-10-26 13:12:02] PDOException: SQLSTATE[HY000]: General error: 7 no
connection to the server in

if I don't use pcntl_fork , nothing

I don't know how to fix it , I need your help

Thank you!