SEARCHING MEANS SELECTING PROGRAM, SEARCHING MEANS SELECTING METHOD AND SEARCHING MEANS SELECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To enable selecting one with shorter searching time between an RDB and a DSE (document search engine) in a Key-Value search.SOLUTION: An RDB cost calculating unit 52 calculates a search cost using an index for each key with reference to a statistical information table, and calculates a search cost of an RDB based on the search cost for each key and a merging cost of a search result for each key. Moreover, a DSE cost calculating unit 53 calculates a search cost using an index for each key with reference to the statistical information table, and calculates a search cost of a DSE based on the search cost for each key and a merging cost of a search result for each key. Further, a determining unit 54 compares the search cost calculated by the RDB cost calculating unit 52 with the search cost calculated by the DSE cost calculating unit 53, and selects either the RDB or the DSE with a smaller search cost.SELECTED DRAWING: Figure 7