Title: Optimized union of non-disjoint distributed data sets
Abstract: In a variety of applications, ranging from data integration to distributed query evaluation, there is a need to obtain sets of data items from several sources (peers) and compute their union. As these sets often contain common data items, avoiding the transmission of redundant information is essential for effective union computation. In this paper we define the notion of optimal union plans for non-disjoint data sets residing on distinct peers, and present efficient algorithms for computing and executing such optimal plans.