Foundations of Web Transactions

Abstract

Abstract.A timed extension of π-calculus with a transaction construct -the calculus Webπ -is studied. The underlying model of Webπ relies on networks of processes; time proceeds asynchronously at the network level, while it is constrained by the local urgency at the process level. Namely process reductions cannot be delayed to favour idle steps. The extensional model -the timed bisimilarity -copes with time and asynchrony in a different way with respect to previous proposals. In particular, the discriminating power of timed bisimilarity is weaker when local urgency is dropped. A labelled characterization of timed bisimilarity is also discussed.

Decidability Results for Dynamic Installation of Compensation Handlers

“…The aborting semantics is used by SAGAs calculi [9], WS-BPEL [26], and others. The preserving semantics is, for instance, the approach of Webπ [22]. Finally, the discarding semantics has been proposed by ATc [3] and TransCCS [12].…”

A Java Inspired Semantics for Transactions in SOC

“…Languages for service orchestration (e.g., WS-BPEL [17]) provide support for distributed transactions and have been modelled extending some process calculi like those in [3,10,12,13] with primitives that allow a party to define the scopes, failure handlers, and compensation mechanisms (see [20] for an overview and a comparison of such approaches). StAC [8] and CJoin [6] are process calculi which model arbitrarily nested transactions and focus on the separation of process management with error/compensation.…”

Modeling Long–Running Transactions with Communicating Hierarchical Timed Automata

“…The alternative to roll-back activities in this kind of transactions is the use of compensations, which are activities explicitly programmed to remove the effects of the actions performed, and may require, for instance, the payment of some kind of penalty. This new kind of transactions are usually called long-running transactions, but they are also known as Sagas [7], web transactions [10] and extended transactions [9]. Although there is an interest for their support in distributed object-based middlewares [9], they are studied in particular in the context of orchestration languages for Web Services (such as BPEL4WS [8] and WSCI [12]).…”

“…Since the specifications of these languages mainly consist in informal textual description of their constructors, there is a strong interest in the formalization of their semantics [4-6, 10, 13]. Among these papers, [6,10] give theoretical foundations to the fragments of orchestration languages describing long-running transactions. In particular, [6] identifies three main composition patterns for transactional activities with compensations, namely sequential composition, parallel composition, and nesting, and provides a formal semantics for them.…”