WAS v8.5 > WebSphere applications > Service integration

Messaging engines

Each service integration server or cluster bus member contains a component called a messaging engine that processes messaging send and receive requests and that can host destinations.

When you add an application server or a server cluster as a bus member, a messaging engine is automatically created for this new member. If you add the same server as a member of multiple buses, the server is associated with multiple messaging engines (one messaging engine for each bus). If the bus member is a WebSphere MQ server, it does not have a messaging engine, but it lets you access WebSphere MQ queues directly from WebSphere MQ queue managers and (for WebSphere MQ for z/OS ) queue-sharing groups.

To host queue-type destinations, the messaging engine includes a message store where, if necessary, it can hold messages until consuming applications are ready to receive them, or preserve messages in case the messaging engine fails. There are two types of message store, file store and data store. For further information, see Administer message stores.

Messaging engines are given a name which is based on the name of the bus member. Each messaging engine also has a universal unique identifier (UUID) that provides a unique identity for the messaging engine.

If you delete and recreate a messaging engine, it will have a different UUID and will not be recognized by the bus as the same engine, even though it might have the same name. For example, the recreated messaging engine will not be able to access the message store the earlier instance used. If you accidentally delete a messaging engine configuration, and save the updated incorrect configuration, you must restore the configuration from a previous configuration backup.

Subtopics

• Mechanisms for stopping messaging engines
  There are several different mechanisms used to stop messaging engines. We can also specify two different degrees of urgency: immediate and force. Stopping a messaging engine prevents it from sending messages.
• Message points
  A message point is associated with a messaging engine and holds messages for a bus destination.
• Messaging engine communication
  We can configure different transport options for communication between messaging engines and with WebSphere MQ networks.
• Security for messaging engines
  When bus security is enabled, you need to be aware of the additional requirements to secure communication between messaging engines.
• Applications with a dependency on messaging engine availability
  If an application depends on a messaging engine being available, then the messaging engine must be started before the application can be run.

Related concepts:

Mediations

Related

Configure messaging engines
Configure messaging engine properties
List the messaging engines defined for a server bus member
List the messaging engines in a bus
Remove a messaging engine from a bus
Create the database, schema and user ID for a messaging engine
Start a messaging engine
Stopping a messaging engine
Display the runtime properties of a messaging engine
Manage messaging engines with administrative commands

Related information:

Messaging engine troubleshooting tips

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