Fusion Query Optimization

Abstract

Fusion queries search for information integrated from distributed, autonomous sources over the Internet. In this context, data is not cleanly fragmented as in traditional distributed databases, and the number of sources participating in a typical query is large. We investigate techniques for effcient processing of fusion queries. First, we focus on a very wide class of query plans that capture the spirit of many techniques usually considered in existing systems. We show how to effciently find, under various realistic scenarios, good query plans within this large class. We evaluate the performance of these plans and provide additional heuristics that, by considering plans outside our target class of plans, yield further performance improvements.