The Globus Toolkit R-tree for partial spatial replica selection

Abstract

Partial Replicas have been used to parallelize access to regions of large spatial data sets on geographically distributed machines, saving network bandwidth and improving data availability. In this paper, we present the Globus Toolkit R-tree, (GTR-tree) to efficiently select partial replicas using the Globus Toolkit Replica Location Service (RLS) middleware. First, the limitations inherent in the Globus RLS service for spatial data are analyzed, motivating the usefulness of the GTR-tree for solving the partial replica selection problem. We then describe our implementation of the R-tree data structure on top of an unmodified Globus RLS. The R-tree is an important data structure for spatial computation, and results in very significant performance gains. Our performance results and evaluation demonstrate enormous improvements for spatial replica selection over a plain RLS.