CiviCRM Community Forums (archive)

There is a logic flaw with 'Daily' scheduled jobs, that will eventually lead to a day where the job is not run, skipping a day.

The logic in 4.5.8 is ...
      case 'Daily':
        $now     = CRM_Utils_Date::currentDBDate();
        $dayAgo  = strtotime('-1 day', strtotime($now));
        $lastRun = strtotime($this->last_run);
        if ($lastRun < $dayAgo) {
          return TRUE;
        }

To see the problem, imagine the cron job is run at times T1, T2, ..., Ti, Ti+1, ..., Tn through the day.

If it runs at time Ti on Day 1, then on Day 2 it will either run at time Ti or Ti+1 (depending on exactly when the job runs). Eventually a day will come when the job runs at time Tn, and the day after that the job will either run at Tn or not at all, as there is no Tn+1.

In that final case, the job will not run until T1 on the subsequent day. In that case a day has been skipped.

A correct solution for daily jobs

To avoid this, $now and $this->last_run should each be converted to a day number. The job should run if day_number($now) != day_number($this->last_run). (I'm suggesting the day number is in the form 20150315.)

A correct solution for hourly jobs

Since the logic for Hourly jobs follows the same pattern as Daily, it has the same problem of skipping an hour. This might not be as serious as skipping a day.

A similar solution also works for 'Hourly' jobs, by running the job if hour_number($now) != hour_number($this->last_run). (the hour number is 0, 1, ..., 23)

A better solution for daily jobs

The solution I propose above for Daily jobs will result in all Daily jobs being run at T1. This might be undesirable.

A better solution might be to define 'hours(x) = 24*day_number(x) + hour_number(x)' and then run the Daily job when ...


Then the job will run in the same hour every day. (To set it to run in a particular hour, run the job manually at that time, and then it will run in that hour from that time on.)

An even better solution for daily jobs

Use a job parameter "not_before=6" to prevent jobs running before 0600 hours.

$now and $this->last_run would each be converted to a day number. If the "not_before" parameter is present, use it, else treat it as zero. The job should run if day_number($now) != day_number($this->last_run) && hour_number($now) >= not_before.

This works as long as no job expects a not_before parameter. (I assume jobs ignore extraneous parameters.)

Jon,

From my observations of the recurring events and activities in 4.6, these are not ongoing happenings but are bound in number of recurrences, dates, etc. My gut feel is this a bit heavyweight.

An even better solution for daily jobs

Use a job parameter "not_before=6" to prevent jobs running before 0600 hours.

$now and $this->last_run would each be converted to a day number. If the "not_before" parameter is present, use it, else treat it as zero. The job should run if day_number($now) != day_number($this->last_run) && hour_number($now) >= not_before.

This works as long as no job expects a not_before parameter. (I assume jobs ignore extraneous parameters.)

Joanne,

Your issue is different to the one I'm discussing.

You can do what you need via the command-line features of CiviCRM. Open http://wiki.civicrm.org/confluence/display/CRMDOC/Managing+Scheduled+Jobs and look for "mail_report" on that page.

The issue I have is that "Daily" is not daily.

Ken

See https://issues.civicrm.org/jira/browse/CRM-16276