Value-Based Notification in Publish/Subscribe Systems
Jeff M Phillips
Summary
Publish/subscribe systems provide a framework for disseminating dynamic data from a set of publishers to a set of subscribers quickly and with low network traffic. By packaging the data cleverly and performing simple calculations on the nodes of the dissemination network, processing and dissemination time can be reduced by several orders of magnitude. Our contribution is for a specific type of data published as a single value where the subscribers only wish to be updated if the data value changes by more than some individualized radius from the last time they received a data value. Consider subscribers who wish to receive stock updatse only when the price changes by more than some value (say $1 for some and $.10 for others). Using several observations about the nature of these updates, we build data structures and protocols which demonstrate orders of magnitude improvement over several alternative approaches.

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Visuals

Example of subscription intervals (S1, S2, S3) and which ones are affected when a published stock price changes.

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Publications

Value-Based Notification Conditions in Large-Scale Publish/Subscribe Systems.
     Badrish Chandramouli, Jeff M. Phillips, Jun Yang. 33rd Intenational Conference on Very Large Data Bases. September 2007.

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