| Parallel Computing Toolbox™ | |
When you create and run a job, it progresses through a number of stages. Each stage of a job is reflected in the value of the job object's State property, which can be pending, queued, running, or finished. Each of these stages is briefly described in this section.
The figure below illustrated the stages in the life cycle of a job. In the job manager, the jobs are shown categorized by their state. Some of the functions you use for managing a job are createJob, submit, and getAllOutputArguments.
Stages of a Job
The following table describes each stage in the life cycle of a job.
Job Stage | Description |
|---|---|
Pending | You create a job on the scheduler with the createJob function in your client session of Parallel Computing Toolbox software. The job's first state is pending. This is when you define the job by adding tasks to it. |
Queued | When you execute the submit function on a job, the scheduler places the job in the queue, and the job's state is queued. The scheduler executes jobs in the queue in the sequence in which they are submitted, all jobs moving up the queue as the jobs before them are finished. You can change the order of the jobs in the queue with the promote and demote functions. |
Running | When a job reaches the top of the queue, the scheduler distributes the job's tasks to worker sessions for evaluation. The job's state is running. If more workers are available than necessary for a job's tasks, the scheduler begins executing the next job. In this way, there can be more than one job running at a time. |
Finished | When all of a job's tasks have been evaluated, a job is moved to the finished state. At this time, you can retrieve the results from all the tasks in the job with the function getAllOutputArguments. |
Failed | When using a third-party scheduler, a job might fail if the scheduler encounters an error when attempting to execute its commands or access necessary files. |
Destroyed | When a job's data has been removed from its data location or from the job manager, the state of the job in the client is destroyed. This state is available only as long as the job object remains in the client. |
Note that when a job is finished, it remains in the job manager or DataLocation directory, even if you clear all the objects from the client session. The job manager or scheduler keeps all the jobs it has executed, until you restart the job manager in a clean state. Therefore, you can retrieve information from a job at a later time or in another client session, so long as the job manager has not been restarted with the -clean option.
To permanently remove completed jobs from the job manager or scheduler's data location, use the destroy function.
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