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How the TEDG Handles Queue Processing
Both the BEA TOP END and BEA Tuxedo systems support reliable queues as a means of passing messages between components. The BEA Tuxedo /Q facility and the BEA TOP END Recoverable Transaction Queuing (RTQ) product allow messages to be passed using a queue as a stable intermediary, capable of storing messages before processing. This model is useful when offline processing of requests is preferred, or when such processing is the only practical method of client/server communication. Both /Q and RTQ guarantee that once a message is successfully placed on a queue it will be delivered to a server. Full transaction semantics are supported for both the original message queuing and the subsequent message processing.
The TEDG supports the queuing of messages between the BEA Tuxedo and BEA TOP END systems, as well as transactional queuing between systems. While /Q and RTQ offer similar capabilities, they are fundamentally different in their approach to handling queued messages.
The BEA Tuxedo system provides a function that allows programs to explicitly dequeue messages (see tpdequeue(3c) in BEA Tuxedo ATMI C Function Reference). Alternatively, a system-supplied service, TMQFORWARD(5), can be configured to dequeue messages automatically and forward them to standard BEA Tuxedo servers via the normal tpcall(3c) function. The destination service is mapped to the queue name.
In contrast, the BEA TOP END system does not provide a dequeuing facility for user programs. Instead, messages are dequeued by the RTQ subsystem, which delivers them to the intended service. The destination service address is supplied as part of the process of enqueuing the message (see tp_rtq_put(3T) in BEA TOP END Programmer's Reference Manual). The relationship between the queues and the services is arbitrary.
See Also
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Copyright © 2001 BEA Systems, Inc. All rights reserved.
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