Efficient and Extensible Multithreaded Remote Servers?
In many cases, servers must impose a protocol of calls to their clients, and at the same time handle multiple client requests. The MT-Rendezvous design pattern greatly simplifies both tasks: separate server threads handle separate clients or sessions, and each different call protocol is handled by means of rendezvous.
One of the most significant performance problems in this kind of system is the latency introduced by network messages exchanged between clients and servers. Another design pattern, CompositeCalls, has been used to achieve dramatic performance improvements. With CompositeCalls clients send entire programs to the server so that the number of messages exchanged can be greatly reduced. Moreover, servers can be dynamically extended by using CompositeCalls.
Therefore, an expressive and effcient server model can be obtained by mixing both patterns within the same framework. However, as both patterns overlap, its integration is not a trivial task.
In this paper we describe how can both patterns be combined, including a brief description for its instantiation in Ada 95. Besides, we show concrete applications where the compound pattern, CompositeRendezvousCalls, can be employed, including a transactional framework for distributed Ada applications, TransLib.
KeywordsDesign Pattern Server Side Interpreter Server Single Call Client Code
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