Event-Driven Database Information Sharing

Database systems have been designed to manage business critical information and provide this information on request to connected clients, a passive model. Increasingly, applications need to share information actively with clients and/or external systems, so that they can react to relevant information as soon as it becomes available. Event-driven architecture (EDA) is a software architectural pattern that models these requirements based on the production of, consumption of, and reaction to events. Publish/subscribe provides a loosely-coupled communication paradigm between the components of a system, through many-to-many, push-based event delivery. In this paper, we describe our work integrating distributed content-based publish/subscribe functionality into a database system. We have extended existing database technology with new capabilities to realise EDA in a reliable, scalable, and secure manner. We discuss the design, architecture, and implementation of PostgreSQL-PS, a prototype built on the PostgreSQL open-source database system.