Replica-aware, multi-dimensional range queries in Distributed Hash Tables

In this paper, we present and evaluate a protocol that enables fast and accurate range-query execution in Distributed Hash Tables (DHTs). Range queries are of particular importance when the network is populated with groups or collections of data items, whose respective identifiers are generated in a way that encodes semantic relationships into key distances. Contrary to related work in the same direction, our proposed query engine is aware of data replicas at the DHT level and by grouping related nodes into replica neighborhoods, resolves queries with the minimum amount of messaging overhead. Moreover, we suggest pairing respective operations with the core DHT routing mechanics, which allows for reusing existing management and monitoring structures and automatically adapting the query path to the dynamic characteristics of the overlay. We also present an application scenario and the respective deployment details of a prototype implementation in the context of the Gredia project. (C) 2010 Elsevier B.V. All rights reserved.