Resources

A job can have different types of dependencies including time, predecessor, and resource. A job runs when it meets all of its dependencies. A job that waits for resources is in the RESWAIT state.

A resource is a job dependency that can be quantified by specifying its availability count. Resource dependencies affect a job's ability to run successfully. The server submits only jobs that have met all their resource requirements.

For example, if a job needs three units of a resource and only two units of the resource are available, the job cannot run (RESWAIT) until all three units of the resource are available.

Each resource is associated with a resource type that determines the resource's properties and behavior.

The following resource types are available:

Depletable resources: A depletable resource is a consumed resource. When the server submits a job, the job permanently removes the consumed units of the depletable resource from the resource pool. When the resource depletes, it can be replenished for other jobs to use. For example, you can use a depletable resource to represent disk space.
Renewable resources: A renewable resource is a borrowed resource. When the server submits a job, the job removes the borrowed units of the renewable resource from the resource pool. The resource units are not permanently used up. The resource units return to the resource pool when the job completes or fails. The job borrows the resource units so it can execute successfully. For example, you can use a renewable resource to control concurrent write access to a database.
Threshold resources: A threshold resource is a sizing resource. A job does not consume or borrow resource units from the resource pool while it runs. For example, if the resource quantity is set to two, the server submits all jobs that require two or fewer units. The server does not submit any job requiring three or more units. It sizes the job against the threshold resource's current level. For example, you can use a threshold resource to represent a period when you run low-priority jobs.