Transactional CSP processes

Abstract

Long-lived transactions (LLTs) are transactions intended to be executed over an extended period of time ranging from seconds to days. A long-lived transaction is normally organized as a series of activities, with each activity being a discrete transactional unit of work that releases transactional locks upon its execution. The long-lived transaction commits if all its activities complete successfully. Unless an activity requires the result of a previously committed activity, there is no constraint which specifies that the various activities belonging to a long lived transaction should execute sequentially. In this paper we present a solution that combines long-lived transactions and CSP such that in- dependent activities execute in parallel to achieve flexibility and better performance for long-lived transactions. We introduce two composition constructs SEQ LLT and PAR LLT. Very much as the occam CSP-based constructs, SEQ and PAR, allow processes to be executed sequentially or concurrently, the proposed SEQ LLT and PAR LLT constructs can be used to specify the sequential or concurrent execution of transactions. Transactional CSP Processes is a framework that makes use of these composition constructs, providing an API through which the application developer can define long-lived transactions. Concurrency and transaction handling are managed by the framework transparently from the application developer.