Priority and Preempt Transaction Attributes

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Predefined transaction attributes Priority and Preempt can affect the flow of transactions through your process. Priority affects the order that transactions are processed, and Preempt affects how resources are acquired.

You can assign the Priority and Preempt attributes to a transaction family to extend the priority or preempt value to all members of the transaction’s family. For example, in an Order Processing model, when the Sales department establishes a priority for an order, all of the related family members (for example, the credit check and the work order) receive the same priority value.

Priority

Specifies the order in which transactions are processed.

The value can be between 0 (lowest priority) and 127 (highest priority)
A higher priority transaction is processed before all lower priority transactions that are waiting.
Two transactions with the same level of priority are processed according to queuing rules (see Transactions Queued at Activities).
A higher priority transaction never acquires resources away from transactions that are already in process (acquired) unless preempt is set.

Preempt

Changes the order in which transactions are processed and works with the priority attribute to create two tiers of order.

The value can be True or False.
A preemptive transaction (Preempt value is True) can acquire resources away from all equal or lower-priority transactions, even if the resource is already in use.
If two transactions have the same priority, a preemptive transaction is processed first.
If two transactions have the same priority and are both preemptive, the transactions are processed in the queue order.