Abstract Optimal and Robust Routing of Subscriptions for Unifying Access to the Past and the Future in Publish/Subscribe

A flexible, scalable, and asynchronous middleware abstract is needed for business process management, which involves thousands of tasks and a large number of running instances of large business processes. The content-based publish/subscribe system is an ideal candidate to serve as enterprise service bus for these applications. In the pub-lish/subscribe paradigm, information providers called publishers disseminate publica-tions to all subscribers who have expressed interests by registering subscriptions through a loosely coupled interface. However, the traditional publish/subscribe paradigm only supports “stateless ” subscriptions, that is, event correlation is ignored. Moreover, sub-scribers can only receive publications issued after their subscriptions. There are many application contexts, however, where access to publications from the past is necessary, such as for replaying a business process execution to debug it. Even more interesting uses arise when data from the past can be correlated with those in the future. Therefore, new languages and new functionalities are needed in the standard publish/subscribe model in order to support business process management. A new subscription language Padres SQL(PSQL) which can express event pattern