Managing Ensemble Productions - InterSystems Documentation

What to Manage
3.10.2 Messages in Progress
It is not always possible for a message to be immediately Delivered. Most host classes provide some level of recovery from
initial obstacles that a message might encounter. Obstacles to delivery might arise for any number of reasons, including
circumstances outside the Ensemble system (an external server goes down) or the need to wait for a decision from another
business process or human participant (workflow). The different message status values help you to track what is happening
to message that are not yet Delivered. Details are as follows:
• In many cases, business operations are designed to retry a message a given number of times, at given intervals, before
declaring the message failed or announcing a timeout. Many outbound adapters offer configurable parameters that
control the time interval and number of retries to make. If this is the case, you can set these values when you configure
Specific Settings for the business operation using the Ensemble Management Portal, without changing any classes in
Studio.
• Some business operations are designed to set the status of any failed messages to Suspended. Alternatively, you can
manually suspend a message from the Instances display on the [Ensemble] > [Host Monitor] page. In either case,
Ensemble automatically places all Suspended messages on a special queue. A system administrator can find these
message on the [Ensemble] > [Maintenance] > [Suspended] page. An inspection of the routing information or contents
of a specific message might reveal the reason why the message failed. For example, if the problem is that an external
destination went out of service, a change can be made to reestablish communication with that server. Then the Suspended
messages can be resent to the external server by clicking a command on the [Ensemble] > [Maintenance] > [Suspended]
page or by clicking Resend Messages on the [Ensemble] > [Messages] page.
• There is a message status that does not indicate either delivery or failure; that is the Deferred status. A business operation
can set the status of a response message to Deferred before it exits. The Deferred response can be picked up and sent
back to the original requester by any business host in the production. Between the time when the business operation
defers the response, and when the response is finally sent, the response message has a status of Deferred. The sender
of the original message is unaware of the fact that the message was Deferred. If the original call was synchronous, the
call does not return to the sender until the deferred response is sent.
3.11 Working with Queues
In the Ensemble context, a queue is simply a list of message objects waiting to be processed by a business host — a business
service, a business process, or a business operation — within a production. No queue setup is required. Ensemble manages
all queues automatically; see the Queues section in the “Ensemble Messages” chapter of Developing Ensemble Productions
for details.
The following portal commands are available to monitor queue status.
Queue Task
List the messages on a specific queue. Provide a facility for viewing these
messages in detail.
Monitor the activities of a message queue in detail.
Quickly view the real-time status of message queues.
Sequence of Portal Commands
Queues, Contents
Queues
System Monitor
Queues offer one of the most useful means of quickly spotting a problem in the system. When there is buildup on a queue,
it usually means something needs to be repaired. For example:
38 Managing Ensemble Productions