Problem

how to use message priority?

Messages are stored in queues with a priority and are processed by procengines according to this priority.

What does it mean?

By default messages will be stored in Integrator internal queues and processed in a FIFO way(first in first out).

How to modify the priority of a message?

It can be done in two ways:
-statically in the integration-task priority can be set via fields Processing priority and Priority
-dynamically via setMessagePriority(...) DML function.

Use cases:

It can be used to prioritize an activity if two activities must be executed in a particular order.
It can be helpful to put a lower priority on the first activities of an integration that receives a big amount of files in order to process completely each message before considering the next one in order to limit the number of messages in Integrator queues.