End-to-end support for joins in large-scale publish/subscribe systems

We address the problem of supporting a large number of select-join subscriptions for wide-area publish/subscribe. Subscriptions are joins over different tables, with varying interests expressed as range selection conditions over table attributes. Naive schemes, such as computing and sending join results from a server, are inefficient because they produce redundant data, and are unable to share dissemination costs across subscribers and events. We propose a novel, scalable scheme that group-processes and disseminates a general mix of multi-way select-join subscriptions. We also propose a simple and application-agnostic extension to content-driven networks (CN), which further improves sharing of dissemination costs. Experimental evaluations show that our schemes can generate orders of magnitude lower network traffic at very low processing cost. Our extension to CN can further reduce traffic by another order of magnitude, with almost no increase in notification latency.