By definition, requestors using tightly coupled mechanisms must wait for the receiver to return a response before they can make a request to a different receiver. A variation on the concurrent execution theme is often found when an application needs to make one or more requests and then immediately move on to other work. Using MQM, applications can send their requests as messages and move on immediately to other tasks. With MQM, no special programming techniques are required. Journaled Communication Most mission-critical environments require the ability to create journals of all communications activity within an application.
Journals contain precise records that can be used by administrators for logging and audit purposes.
In tightly coupled distributed, network-based applications, journaling is particularly difficult because most communications mechanisms do not save any record of their activities after they complete a request. State is kept only for the duration of the round trip between sender and receiver. If an error occurs later in a component of a distributed application, recovery procedures rapidly become complex. Because MQM messages represent encapsulated requests for services, MQM products are able to offer message journaling as a selectable option. When journaling is enabled for a given queue or message, MQM products automatically make a copy of each message for the associated journal queue.