After php upgrade pcntl_fork causing "errno=32 Broken pipe" - php

Question

I recently upgraded from php 5.4.26 to 5.4.28 after the upgrade I am getting this error
Notice: Unknown: send of 6 bytes failed with errno=32 Broken pipe in Unknown on line 0
When ever I run the following code:
<?php
$tasks = array(
'1' => array(),
'2' => array(),
);
ini_set('display_errors', true);
class RedisClass {
private $redis;
public function __construct()
{
$this->redis = new Redis();
$this->redis->connect('localhost', 6379);
}
}
$redis = new RedisClass();
foreach ($tasks as $index => $task)
{
$pid = pcntl_fork();
// This is a child
if($pid == 0)
{
echo "Running ".$index." child in ". getmypid() ."\n";
break;
}
}
switch($pid)
{
case -1 :
die('could not fork');
break;
case 0:
// do the child code
break;
default:
while (pcntl_waitpid(0, $status) != -1)
{
$status = pcntl_wexitstatus($status);
echo "Child completed with status $status\n";
}
echo "Child Done (says: ". getmypid() .")";
exit;
}
If I only fork one child then I do not get the PHP Notice. If I run any more than 1 child I get the PHP Notice for every child except the first child.
Does anyone have any clues as to what is going on here?
I am assuming it is trying to close the Redis connection multiple times but this is code I have been running for at least 4 months with out any issues.
It only starting displaying these notices after the upgrade to 5.4.28.
I have looked at the PHP change logs but I cannot see anything that I think may explain this issue.
Should I report this to PHP as a bug?
UPDATE:
Looks like it "may" be a Redis issue, I am using phpredis I tested the same code with a mysql connection instead of loading Redis and I do not get the error.
class MysqlClass {
private $mysqli;
public function __construct()
{
$this->mysqli = mysqli_init(); //This is not the droid you are looking for
$this->mysqli->real_connect('IP_ADDRESS',
'USER_NAME',
'PASSWORD');
}
}
$mysql = new MysqlClass();

Answer 1

The problem here is that you do not reconnect Redis in the child process. Like Michael had said, you do not have an active connection from the second child onwards. That mysql example should not work if you also make some queries.
I have had the exact problematic behaviour with the "MySQL server has gone away" error and also with Redis.
The solution is to create a new connection to MySQL and to Redis in the child. Make sure if you have a singletone that handles the MySQL/Redis connection to reset the instances ( that was also a problem for me ).