Job Waits and Checkpoints¶
The Wait, Wait until a time and Checkpoint steps pace a job. The Hub keeps all three itself, and none of them is sent to a site. They differ in what ends them and in whether the site keeps its in-progress place while it waits.
| Step | Ends when | Keeps its in-progress place |
|---|---|---|
| Wait | The number of seconds has passed | Yes |
| Wait until a time | The site's own clock reaches the time | No |
| Checkpoint | The preparer or the approver continues the job | No |
A site that gives up its place queues for a free one when its wait ends, after the sites already under way and before any new site. See Running a Job.
Wait¶
Each site waits the number of seconds in Wait (seconds), 1 or more, before its next step. The site keeps its in-progress place while it waits, and the time keeps counting while the job is paused. While it waits, the site's status reads "waiting until" the time the wait ends, in the Hub's time zone.
Wait Until a Time¶
Each site waits until its own clock shows the time in Time (HH:mm), from 00:00 to 23:59. The time is read in the site's own time zone: the default time zone of the site's Java process, which the site reports to the Hub each time its tunnel connects. A job across sites in several time zones therefore runs this step at the same local hour at each site, not at the same moment.
The Hub works out when the wait ends as the site reaches the step:
- A time already passed today means that time tomorrow.
- A time that a daylight-saving change skips means the moment the clocks change.
- A time that a daylight-saving change repeats means its first occurrence.
- A site whose time zone the Hub does not know fails the step, with "site time zone unknown".
The site gives up its in-progress place while it waits, so other sites can carry on. When its time comes, it queues for a free place, so the job's in-progress limit still paces the steps that follow, such as a restart in a quiet hour. A wait that comes due while the job is paused carries on when the job is resumed. The site's status shows the time the wait ends in the Hub's time zone.
Checkpoint¶
A checkpoint holds every site at that step until the preparer or the approver continues the job. No site goes past the checkpoint until every site has reached it or ended, which gives people a chance to review the results first.
A site at a checkpoint gives up its in-progress place, so the sites still waiting to start can reach the checkpoint too. The site's status reads "at the checkpoint" with the step number.
Continue appears in the job's details, for the preparer and the approver, once every site has reached the checkpoint or ended. It is offered only while the job is running, not while it is paused. Its tooltip names the step it continues past. Clicking it releases every site at that checkpoint, and each then queues for a free in-progress place. A site that failed or was not run does not hold the checkpoint up.
A job can have more than one checkpoint. Each Continue releases the next one.
Stopping at a Wait or a Checkpoint¶
When a job is stopped, or halts at its failure limit, a site at a Wait, a clock-time wait or a checkpoint ends where it is. A site that reaches a wait or a checkpoint after that also ends there. See Running a Job.