Analysis of repeated hashing

Abstract

A performance analysis of an overflow handling method for hash files, here called repeated hashing, is reported. The basic idea of repeated hashing is to rehash the overflow records into a smaller separate storage area; the overflow records from this area are in turn hashed into a still smaller separate storage area, etc. The expected retrieval performance and the storage requirements are analysed, both for initial loading and steady state. The problem of optimally partitioning the total storage area is considered and the optimal solution is given. It is concluded, however, that the usefulness of repeated hashing is in doubt because there are methods having the same performance but requiring less maintenance.