Towards Scalable Publish/Subscribe Systems

Despite suffering from inefficiency and flexibility limitations, the filter-based routing (FBR) algorithm is widely used in content-based publish/subscribe (pub/sub) systems. To address its limitations, we propose a dynamic destination-based routing algorithm called D-DBR, which decomposes pub/sub into two independent parts: Content-based matching and destination based multicasting. D-DBR exhibits low event matching cost and high efficiency, flexibility, and robustness for event routing in small-scale overlays. To improve its scalability to large-scale overlays, we further extend D-DBR to a new routing algorithm called MERC. MERC divides the overlay into interconnected clusters and applies content-based and destination-based mechanisms to route events inter- and intra-cluster, respectively. We implemented all algorithms in the PADRES pub/sub system. Experimental results show that our algorithms outperform the FBR algorithm.