File organization using composite perfect hashing

Abstract

Perfect hashing refers to hashing with no overflows. We propose and analyze a composite perfect hashing scheme for large external files. The scheme guarantees retrieval of any record in a single disk access. Insertions and deletions are simple, and the file size may vary considerably without adversely affecting the performance. A simple variant of the scheme supports efficient range searches in addition to being a completely dynamic file organization scheme. These advantages are achieved at the cost of a small amount of additional internal storage and increased cost of insertions.