Providing e-Transaction Guarantees in Asynchronous Systems with No Assumptions on the Accuracy of Failure Detection

In this paper, we address reliability issues in three-tier systems with stateless application servers. For these systems, a framework called e-Transaction has been recently proposed, which specifies a set of desirable end-to-end reliability guarantees. In this article, we propose an innovative distributed protocol providing e-Transaction guarantees in the general case of multiple, autonomous back-end databases (typical of scenarios with multiple parties involved within a same business process). Differently from existing proposals coping with the e-Transaction framework, our protocol does not rely on any assumption on the accuracy of failure detection. Hence, it reveals suited for a wider class of distributed systems. To achieve such a target, our protocol exploits an innovative scheme for distributed transaction management (based on ad hoc demarcation and concurrency control mechanisms), which we introduce in this paper. Beyond providing the proof of protocol correctness, we also discuss hints on the protocol integration with conventional systems (e.g., database systems) and show the minimal overhead imposed by the protocol.