Issue cron is queuing tasks and accumulating them on hold

[Daniel Pereyra]

I have setup a cron to run every minute, seeing the cron log, is running, so that is ok.

* * * * * /opt/plesk/php/7.1/bin/php -f '/var/www/vhosts/domain***/adm/test.php'

The cron I have setup is a simple php file that logs the time this file is executed.

date_default_timezone_set('America/New_York');
$date = date("Y-m-d H:i:s");
$file = __FILE__;
$level = "warning";
$message = "[{$date}] [{$file}] [{$level}] execution".PHP_EOL;
error_log($message, 3, '/var/www/vhosts/domain***/logs/domain***/my-errors.log');

The issue is that this task is for some reason, randomly put to queue, so for example I have this task repeated 5 times, 4 times, or 3 times, instead of one per minute.

This are the cron logs

Oct 1 10:01:01 localhost CROND[2315]
Oct 1 10:02:01 localhost CROND[2388]
Oct 1 10:03:01 localhost CROND[2440]
Oct 1 10:04:01 localhost CROND[2493]
Oct 1 10:05:01 localhost CROND[2566]
Oct 1 10:06:01 localhost CROND[2627]
Oct 1 10:07:01 localhost CROND[2743]

This are the task logs

Monday, 01-Oct-2018 10:00:01 EDT
Monday, 01-Oct-2018 10:05:42 EDT
Monday, 01-Oct-2018 10:05:42 EDT
Monday, 01-Oct-2018 10:05:42 EDT
Monday, 01-Oct-2018 10:05:42 EDT
Monday, 01-Oct-2018 10:05:42 EDT
Monday, 01-Oct-2018 10:06:01 EDT
Monday, 01-Oct-2018 10:07:01 EDT

Someone else told me to create a bash script and test the same thing with cron:

Script:

#!/bin/bash
echo $(date);
exit 0

Crontab:

* * * * * /var/www/vhosts/domain***/test.sh >> /var/www/vhosts/winnersmartialarts.com/logs/domain***/date.log

But the results surprised me, they are great:

Tue Oct 2 05:08:01 EDT 2018
Tue Oct 2 05:09:01 EDT 2018
Tue Oct 2 05:10:01 EDT 2018
Tue Oct 2 05:11:01 EDT 2018
Tue Oct 2 05:12:01 EDT 2018
Tue Oct 2 05:13:01 EDT 2018
Tue Oct 2 05:14:01 EDT 2018
Tue Oct 2 05:15:01 EDT 2018
Tue Oct 2 05:16:01 EDT 2018
Tue Oct 2 05:17:01 EDT 2018
Tue Oct 2 05:18:01 EDT 2018
Tue Oct 2 05:19:02 EDT 2018
Tue Oct 2 05:20:01 EDT 2018
Tue Oct 2 05:21:01 EDT 2018
Tue Oct 2 05:22:01 EDT 2018
Tue Oct 2 05:23:01 EDT 2018
Tue Oct 2 05:24:01 EDT 2018
Tue Oct 2 05:25:01 EDT 2018
Tue Oct 2 05:26:01 EDT 2018
Tue Oct 2 05:27:01 EDT 2018
Tue Oct 2 05:28:01 EDT 2018
Tue Oct 2 05:29:01 EDT 2018
Tue Oct 2 05:30:01 EDT 2018
Tue Oct 2 05:31:01 EDT 2018
Tue Oct 2 05:32:01 EDT 2018
Tue Oct 2 05:33:01 EDT 2018
Tue Oct 2 05:34:01 EDT 2018
Tue Oct 2 05:35:01 EDT 2018
Tue Oct 2 05:36:02 EDT 2018
Tue Oct 2 05:37:01 EDT 2018
Tue Oct 2 05:38:01 EDT 2018

So what do you think this is? An Apache issue? PHP issue?
Any help would be appreciated. Thank you.