Scheduler Best Practices

Avoid Scheduling Jobs Near the Transition Hours of Daylight Savings Time

Every time-based job trigger is exposed to issues caused by the transition from and to Daylight Savings Time. Since the transition involves the server time fast-forwarding or rolling back a certain amount of time on a certain date, this means that a job might trigger more often than expected or not trigger at all on those dates.

For this reason, it is recommended to avoid scheduling OLAP or Distribution jobs on the day and time of that transition to avoid such issue that might lead to unexpected behavior.

Note

Specifics of the transition hour and the amount of time the clock moves forward or back varies by locale; see https://en.wikipedia.org/wiki/Daylight_saving_time_by_country.

As an example of possible issues, scheduling in the United States within locations that observe Daylight Savings Time (DST), the following problems may occur if scheduling jobs on Sundays between 12:00 a.m. and 3:00 a.m.:

  • A job scheduled at 1:05 a.m. may occur twice when DST ends.

  • A job scheduled at 2:05 a.m. may not trigger when DST starts.

  • A job scheduled every 30 minutes from 12:00 a.m. to 3:00 a.m. may run an extra 2 times when DST ends.

  • A job scheduled every 30 minutes from 12:00 a.m. to 3:00 a.m. may skip 2 executions when DST starts.