A declustering algorithm for minimising spatial join cost

Abstract

Spatial joins are important, yet time-consuming operations in spatial databases. In this paper we consider to minimise the I/O cost for the spatial join processing. A graph model is proposed to formalise the cost, and an algorithm originally proposed for distributed database design is adapted for spatial object declustering. We improve the algorithm by giving special consideration to the clusters with overlapped objects. Our algorithm can not only reduce the number of objects fetched from disk for refinement processing, but also be computationally more efficient than the previous algorithms