Measuring Fuzzy Atomicity for Composite Service Execution

The ACID (Atomicity, Consistency, Isolation, and Durability) model has played a cornerstone role in service composition to guarantee that Composite Services (CSs) have transactional support and consistent outcomes ("all-or-nothing" property). However, the classical "all-or-nothing" model is too restrictive for loosely coupled and distributed environments as Internet. Some approaches have been proposed to relax atomicity based on transactional properties of services, using compensation mechanisms or providing checkpointing techniques. In this article, we propose a model that measures the fuzzy atomicity of a composite service based on transactional properties and on the checkpointing mechanism, relaxing the "all-or-nothing" property into a new a fuzzy "all-something-or-(almost) nothing" property. The proposed measure takes into account the acceptable fuzzy atomicity expressed in the user requirements (i.e., the minimum result that user can accept), but also the state of the composite service execution. As far as we know, no such a model exists.