Democratizing transactional programming

Abstract. The transaction abstraction is arguably one of the most ap-pealing middleware paradigms. It lies typically between the programmer of a concurrent or distributed application on the one hand, and the oper-ating system with the underlying network on the other hand. It encapsu-lates the complex internals of failure recovery and concurrency control, significantly simplifying thereby the life of a non-expert programmer. Yet, some programmers are indeed experts and, for those, the trans-action abstraction turns out to be inherently restrictive in its classic form. We argue for a genuine democratization of the paradigm, with dif-ferent transactional semantics to be used by different programmers and composed within the same application. 1 A Brief History of Transaction The transaction abstraction is in essence a middleware paradigm: it allows mul-tiple processes running on one or more processors (machines) to interact. The transaction abstraction lies typically between the programmer of concurrent an