On GDM allocation method for partial range queries

摘要

Almost all the efforts devoted to the multi-disk file allocation problem have been concentrated on partial match retrieval so far, while the study of that for range retrieval is less progressive. This paper is concerned with the multi-disk file allocation problem for partial range retrieval. We particularly concentrate on the performance analysis of GDM (Generalized Disk Modulo) allocation method for partial range retrieval. A performance formula for evaluating the average response time of this allocation method over all possible partial range queries is derived first. Then, based on this formula, we investigate the optimality property of the GDM allocation method for partial range queries. It is shown that the GDM allocation method still guarantees strictly optimal performance for partial range queries under many conditions occurring commonly in practice.