Method and apparatus for finding nearest logical record in a hash table

Abstract

A method, apparatus, software and data structure is disclosed for more efficient access times for linear operations in a hash table, including finding the nearest logical record. A plurality of actual data records and a plurality of marker data records are inserted in a hash table using a hash function. The actual data records and marker data records have a logical ordering specified by a key and are threaded into the hash table to allow linear access by walking the hash table. The logical ordering of the actual data records and marker records is lost upon entry into the hash table, and the keys of the marker data records are distributed at known positions throughout the range of the keys of the actual data records. If when hashing a given key no record exists in the database for the given key, one of the keys for the marker data records are hashed to locate the associated marker data record in the hash table. A nearest logical record may thus be retrieved entering the hash table through the marker data record.

Dependencies are inferred from the claim text.