Process Notification Messages Exactly Once in Order

Use

By selecting this checkbox, you can specify that the notification messages are delivered in accordance with the delivery type Exactly Once in Order (EOIO).

If you use the setting at agent instance level, each notification message that is generated is an EOIO notification message. However, you can also make the EOIO setting on the Message Delivery tab of a notification so that the setting only applies to specific notifications. As a result, there might be EOIO notification messages alongside non-EOIO notification messages in the agent instance queue that are delivered in different ways:

EOIO notification messages are delivered individually and exactly in the order in which they were placed in the queue.

The names of the notifications and the names of the destination system assignments to the notifications determine the order in which notification messages are placed in the queue. If an event occurs at a source system that meets the trigger conditions of multiple notifications, the notifications are processed in alphabetical order. If multiple destination systems are assigned to a notification, the name of the destination system assignment determines the order in which the notification messages are placed in the queue (see also: Destinations Tab.) You can change the sequence by renaming the notifications or destination system assignments to a notification.

If an EOIO notification message cannot be delivered, this notification message blocks the sending of any further EOIO notification messages to prevent one of these other messages being delivered first.

An EOIO notification message that cannot be delivered remains in the main queue until it can be delivered successfully. If the maximum number of retries is reached and the EOIO notification message could still not be delivered, PCo stops the agent instance. The failed EOIO notification message remains in the main queue so that it can be sent again as soon as you restart the agent. (See also: Notification Message Queue and Dispatch Settings.)

Non-EOIO notification messages are sent in parallel processes. For this, you can specify the maximum number of dispatch threads. PCo tries to automatically resend non-EOIO notification messages that could not be delivered successfully. (See: Notification: Reliable Connection Tab and Agent Instance: Displaying Messages.)