CorONA: A High-Performance Publish-Subscribe System for Web MicroNews
CorONA is a high-performance publish-subscribe system for quick and
efficient dissemination of web micronews. It is a replacement for, and
is backwards compatible with, RSS. It uses
an analysis-driven framework for optimally trading off bandwidth
for performance, to provide low-latency news dissemination
while ensuring that the load placed on news providers does
not exceed a desired limit.
The current RSS system causes serious load problems for news providers.
Currently, every client periodically checks every news source, consuming
significant bandwidth. Further, RSS demand is "sticky," that is, once
subscribed, clients remain subscribed. Hence a site whose popularity
temporarily surges ends up having to deal with a large constant load
CorONA fixes the load problem by intelligently trading off resources
for quick update performance. It operates as a ring of cooperative
proxy servers, each of which periodically poll news providers. When a
client signs up for a channel, a fraction of the servers are dedicated
to polling the news providers, while the ring records the interests
expressed by the client. The number of servers dedicated to checking
the channel and disseminating the news is determined optimally,
based on an analysis of web object popularity, size, and update rate.
Users interact with Corona entirely through instant messages: