Index managing unit, index updating method, index managing method, computer-readable recording medium retaining an index updating program, and computer-readable recording medium retaining an index managing program

Abstract

The present invention relates to an index managing unit which comprises an index storage managing section for managing content information corresponding to key information constituting an index on a storage area, a management information storage managing section for managing management information about the index on the storage area, and a management information updating section for updating the management information on the basis of record information inputted as information to be added to the index and constructed in units of a set of key information and content information. The index storage managing section is composed of an area calculating section for calculating, through an arithmetic, a free area to be set when necessary on the basis of the management information at the updating of the index and an area allocating section for allocating the storage area for the storage of the index on the basis of the calculated free area. Thus, the allocation of an area for an index having a data structure where the lengths of the record portions depend upon keys to extremely differ from each other is effectively possible through the use of statistics information about the index such as the occurrence frequency of record information at every key.