How can we support Grid Transactions? Towards Peer-to-Peer Transaction Processing

Today, we witness a merger between Web services and grid technology towards an open grid service infrastructure that especially satisfies the demands of complex computations on huge volumes of data. Such applications are specified as combinations of services and are executed as workflow processes. While transactional support was neglected for (business) workflows, in the grid domain we observe not only a more general usage of workflow technology but also a stronger awareness of transactional guarantees. The rigid database notions of atomicity and isolation are however not suited for composite services in grid applications because of their complexity and duration. Beyond, the level of abstraction in the grid is far above database pages such that two-phase commit combined with two-phase locking as the state-of-the-art for distributed transactions is not adequate. Rather, compensation of services, restarting services, and invoking alternative services are needed. In this context many questions are open. How does the infrastructure detect and handle conflicts? What happens if a service is unavailable? Can we locally decide whether a distributed execution of transactions is globally correct? In this paper, we tackle some of these questions and sketch an approach to ensuring globally correct executions of transactional processes without a global coordinator. ∗Papers on “Transactions” are no longer desired in our mainstream conferences. Nevertheless, we are convinced that much work is still needed and useful, especially with respect to newer computing paradigms. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Very Large Data Base Endowment. To copy otherwise, or to republish, requires a fee and/or special permission from the Endowment. Proceedings of the 2005 CIDR Conference