Processing and optimization of multiway spatial joins using R-trees

Abstract

One of the most important types of query processing in spatial databases and geographic information systems is the spatial join, an operation that selects, from two relations, all object pairs satisfying some spatial predicate. A multiway join combines data originated from more than two relations. Although several techniques have been proposed for pairwise spatial joins, only limited work has focused on multiway spatial join processing. This paper solves multiway spatial joins by applying systematic search algorithms that exploit R-trees to efficiently guide search, without building temporary indexes or materializing intermediate results. In addition to general methodologies, we propose cost models and an optimization algorithm, and evaluate them through extensive experimentation.