Need a way to selectively kill sleeping php processes - php

Question

I have a website that periodically gets a large number of sleeping php processes. My hosting service sets a limit of 20 concurrent running processes. If it goes over the limit my site goes down with a 503 error.
It is a rare occurrence and doesn't seem to have any correlation to the number of people visiting my site.
As a safeguard I would like to have a cron job with a php script that would kill php processes that have been sleeping for over 10 min.
I have a php function that will kill all sleeping MySql processes that have been sleeping for more than 10 min;
public function kill_sleeping_mysql_processes()
{
$result = $this->db->query("SHOW FULL PROCESSLIST");
foreach($result->result_array() as $row)
{
if ($row['Command'] == "Sleep" && $row['Time'] > 600)
{
$this->db->query("KILL {$row['Id']}")
}
}
}
The question is how can do I do the same with php processes?
I can get a read out of php processes with this code.
exec("ps aux | less", $output);
and I can kill specific php processes with this code if I have the pid;
$pid = 11054;
exec("kill -9 $pid");
But how can I selectively kill php processes that have been sleeping more than 10 min?

Answer 1

I cobbled something together. It is not elegant and is a bit of a hack but it seems to work, although I am going to test it further before putting in a cron job.
public function kill_dormant_php_processes()
{
$output_array = array();
exec("ps aux | grep -v grep", $ps_output);
array_shift($ps_output);
if (count($ps_output) > 0)
{
$i = 0;
foreach ($ps_output as $ps)
{
$ps = preg_split('/ +/', $ps);
$output_array[$i]->pid = $ps[1];
$output_array[$i]->stat = $ps[7];
$output_array[$i]->time = $ps[9];
$i++;
}
}
if( ! empty($output_array))
{
foreach ($output_array as $row)
{
if( $row->stat == 'S' && date('H:i', strtotime($row->time)) > date('H:i', strtotime('00:01')))
{
exec("kill -9 $row->pid");
}
}
}
}
I am sure there must be a better way to do it.
Could someone explain why 00:01 in the read out seems to translate to 6 min?
freedom 6933 6.0 0.1 57040 13040 ? S 16:55 0:01 /usr/local/bin/php53.cgi -c .:/home/freedom/:/etc index.php

Answer 2

As an alternative to the PHP script shared here, you can use the killall command with an "older than" time filter (using the -o option) to kill all those processes.
This command for example will kill all php-cgi processes that have been running for more than 30 minutes:
killall -o 30m /usr/bin/php-cgi