Some Properties of Cartesian Product Files for Disk Modulo Allocation Method in a Two-disk System
C.C. CHANG Institute of Applied Mathematics, National Chung Hsing University, Taichung, Taiwan 40227, Republic of China C. Y. CHEN Department of Electronics, Feng Chia University, Taichung, Taiwan 40734, Republic of China
In this paper, we consider the following problem: Given a set of multi-attribute records, a fixed number of buckets and a two-disk system, design an optimal Cartesian product file for Disk Modulo allocation method, in such a way that the average response time over all possible partial match queries is minimized (i.e., the maximal possible disk access concurrency is achieved for examining the required buckets). For the case where the number of buckets is a power of odd prime, a very efficient algorithm. which can he applied to design the optimal Cartesian product file for Disk Modulo allocation method in a two-disk system, is proposed. We further show that this algorithm guarantees for optimal solutions to be produced in this case. We also propose a heuristic algorithm to design "good" Cartesian product files in general.