JAMS and Daylight Savings Time


JAMS automatically handles Daylight Savings Time adjustments based on the Operating Systems time-zone settings.

What happens to a job scheduled for 02:00 AM every day?

In the United States, when the clock is moved forward in the spring, no instance of 02:00 AM occurs, JAMS will immediately detect that the job scheduled for 02:00 AM is late at 03:00 AM and attempt to run the job immediately.

In the fall, when two occurrences of 02:00 AM occur, JAMS would schedule the 02:00 AM instance and understand that it has already generated the schedule to a given time. JAMS maintains how far it has advanced the schedule with the ScheduleUntil value of the its configuration settings. Because JAMS generates schedules and knows how far it has advanced a schedule, only one instance of the 02:00 AM job will run.



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    Pat Marshall

    What will happen for jobs scheduled between 2 and 3? When springing forward to 3, I assume they will run immediately, but will it detect that the job has already run when falling back?

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    Glenn McKinnon

    Hi Pat - correct, JAMS will detect the Job has already executed. JAMS maintains it's future schedule using the "ScheduledUntil" Config Item, and therefore will have already scheduled the Job/s and perhaps already executed them.

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    Doreen Yau

    We have a big workflow which begin at 12:45am consist of multiple sequences. There is one sqeuence starting at 2:00am, another at 2:15am, another at 2:45am, and one more at 3:00am. Based on the explanation above, the 2am sequence and 3am sequence will kick off same time where as the 2:15am will kick off at 3:15am; 2:45am at 3:45am. This will result in the 2:15am and 2:45am sequence execute after 3am sequence which is not really what we intended. Looks like we need to make some adjustment manually still.

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    Gennaro Piccolo

    Hello Doreen, that is not correct. JAMS will schedule the jobs based on what the time will be after the time change. The 3am sequence will still run at 3am, and the 2am sequence will still run at 2am.

    The clock is set back to 1am 1 second after 1:59:59am, and then 2am will occur exactly one hour after that, and 3am will occur exactly one hour after that time.

    While those times would be inaccurate in the daylight savings time period, they are technically correct for the non-daylight savings time period.

    If your organization needs to execute the jobs based on a purely logical time period independent of what daylight savings is dictating, then yes, I would look into setting the schedule differently rather than following what the "generally agreed upon" time would currently be in the United States for that date.