Processing constrainedK closest pairs query in spatial databases

In this paper, constrainedK clost pairs query is introduced, which retrieves theK closest pairs satisfying the given spatial constraint from two datasets. For data sets indexed by R-trees in spatial databases, three algorithms are presented for answering this kind of query. Among of them, two-phase Range + Join and Join + Range algorithms adopt the strategy that changes the execution order, of range and closest pairs queries, and constrained heap-based algorithm utilizes extended distance functions to prune search space and minimize the pruning distance. Experimental results show that constrained heap-based algorithms has better applicability and performance than two-phase algorithms.