Why does Cron NOT work consistently?

Question

Task Schedulers

It is very important for me to run CRON every minute, I issue the following command:

/usr/bin/wget -O - -q -t 1 http://www.123.com/script/start.php

It works, but I decided to record the time in a file so that I can clearly see when CRON starts and this is what I get:

2019-05-11 11:44:02
2019-05-11 11:46:03
2019-05-11 11:47:02
2019-05-11 11:48:01
2019-05-11 11:49:02
2019-05-11 11:50:02
2019-05-11 11:51:02
2019-05-11 11:52:01
2019-05-11 11:53:02
2019-05-11 11:54:02
2019-05-11 11:55:02 ******
2019-05-11 11:57:02 ******
2019-05-11 11:58:03
2019-05-11 11:59:01
2019-05-11 12:01:02 ******
2019-05-11 12:03:02 ******
2019-05-11 12:04:02 ******
2019-05-11 12:06:03 ******
2019-05-11 12:07:02
2019-05-11 12:08:02
2019-05-11 12:09:02
2019-05-11 12:10:04 ******
2019-05-11 12:12:03 ******
2019-05-11 12:13:02
2019-05-11 12:14:03 ******
2019-05-11 12:16:03 ******
2019-05-11 12:17:02 ******
2019-05-11 12:19:02 ******
2019-05-11 12:20:02

I highlighted * moments where the script does not run (skip 1st minute) sometimes it skips 2-3 minutes.
There is nothing in the Error log except for the error Could not execute scriptthat I discussed here
The hoster refers to a mysql error, they say crons do not close the connection to the database, but in fact I did it, and now the connection is closed, but the error has not disappeared. (Mysql errors I write to a file - they are not there).
It turns out that the whole problem is that with some calls we get an error and Cron does not start? Or maybe I specified the command incorrectly somehow?)

Answer 1

This is not a cron issue.

I decided to record the time in a file

is a good debugging technique, but: are you making this entry from your start.php?
Then you're missing the case that wget ran but start.php didn't. This is probably your case. Keep debugging, make wget log.