[SalesForce] What’s the difference between AsyncApexJob and CronTrigger

Roughly I know that when I schedule a Schedulable, I'm creating both a CronTrigger and an AsyncApexJob, but I'm confused as to how the two objects relate to each other and what the significance of each is.

For example, if I'm looking at all scheduled jobs, I can look at the unfired triggers or filter on status for the async jobs. What are the pros and cons of examining one over examining the other?

Best Answer

CronTrigger is the parent job that will be run; it can have many runs attached to it. AsyncApexJob is a single job, including batchable, queueable, and future methods. So, if you want to know what's coming up, CronTrigger will let you know what's scheduled, while AsyncApexJob shows prior executions. If you want to know what's already run, AsyncApexJob is the the best choice, while if you want to know what's coming up, CronTrigger is the best.

Update

While this is marked as fixed this issue still continues to come up from time to time. Fortunately Salesforce support can run a quick fix to address. Contact them and ask to run "fix for locked scheduled class" and include the deployment error message.

[SalesForce] Need System.schedule cron string for run once

You can do either option (both are viable).

To specify a run-once schedule, specify a fully qualified date and time, such as:

0 0 0 4 JUL ? 2014
| | | | |   | |
| | | | |   | \------- YEAR (2014)
| | | | |   \--------- DAY_OF_WEEK (NOT_SPECIFIED)
| | | | \------------- MONTH (JULY)
| | | \--------------- DAY_OF_MONTH (4th)
| | \----------------- HOUR (0- MIDNIGHT LOCAL TIME)
| \------------------- MINUTE (0)
\--------------------- SECOND (0)

This would run at midnight of the scheduling user on the Fourth of July this year, and never again.

If you want to kill other jobs, you simply query for scheduled jobs that are not already cancelled, and then call System.abortJob on those ID values. See CronTrigger for more information.

Finally, you can also abort the current job in the execute() method:

public void execute(SchedulableContext sc) {
    // Do stuff here
    System.abortJob(sc.getTriggerId());
}

Best Answer

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Update

[SalesForce] Need System.schedule cron string for run once

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