Data sharing vs. message passing: synergy or incompatibility?

Abstract

One reasonable categorization of coordination models is into data sharing or message passing, based on whether the information necessary to coordination is persistently stored and shared, or instead is only transiently available during communication. Generally speaking, approaches based on data sharing are more expressive and provide full decoupling in space and time. The alternative approach requires the simultaneous presence of the coordinated parties, but is typically more scalable. Prominent examples are, respectively, tuple spaces and publish-subscribe.An open research question is whether it is possible to exploit in synergy the best of these two approaches, e.g. by implementing the more complex data sharing coordination on top of the more lightweight message passing one. In this paper, we seek an answer to this question in a pragmatic way: we analyze an implementation of the LIME tuple space middleware on top of REDS, an open source publish-subscribe system. Our implementation-driven style of investigation forces us to face details that do not surface when reasoning in the abstract about the nature and expressiveness of the models. We report about lessons we learned in this experience, and propose an extension to the publish-subscribe model that, albeit useful per se, constitutes a more effective foundation for data sharing coordination models.

Layered Connectors

“…Therefore, other middleware solutions have been proposed in order to reconcile the differences between middleware [10]. However, when these middleware solutions follow different interaction patterns, e.g., shared memory and publish/subscribe, the differences are such that they cannot always be solved [7].…”

Service-Oriented Distributed Applications in the Future Internet: The Case for Interaction Paradigm Interoperability

“…Following a similar approach, an API conforming to one interaction paradigm can be locally mapped to an interaction protocol conforming to another paradigm. Thus in [8], the authors implement the LIME TS middleware on top of a PS substrate. Similarly, work in [9] enables Web services SOAP-based interactions over a TS binding.…”

“…Existing cross-domain interoperability efforts are based on, e.g., bridging communication protocols [5], wrapping systems behind standard technology interfaces [6], and providing common API abstractions [7][8][9][10]. In particular, such techniques have been applied by the two currently dominant system integration paradigms, that is, service oriented architecture (SOA) and enterprise service bus (ESB) [11].…”

Tuple Spaces Implementations and Their Efficiency

“…When considering distributed applications, the limited use of the Linda coordination model is also due to the need of guaranteeing consistency of different tuple spaces. In fact, in this case, control mechanisms that can significantly affect scalability are needed [12].…”