Analysis and comparison of declustering schemes for interactive navigation queries

Declustering schemes enable parallel retrievals of raster-spatial data by allocating data among multiple disks. Previous work in the literature has focused on static range queries. In this paper, we focus on interactive navigation queries, which exhibit a new class of data access patterns. We analyze and compare the performance of previously known declustering schemes from the perspective of navigation queries. These schemes include a class of latin-square-based schemes, Disk Modulo, Fieldwise Exclusive-OR, Hilbert Curve Allocation Method, and a random assignment scheme. We show that, unlike the case of range queries, disk module outperforms other schemes and gives nearly optimal performance for navigation queries. In addition, we propose a new scheme under the constraint of bounded window size-a common constraint in practice due to resource limitation such as monitor resolution or memory size. Through extensive analysis, we establish guidelines on how these schemes can be tuned to provide guaranteed performance under the constraint of bounded window size.