Method for cost-based optimization over multimeida repositories

摘要

A method for optimizing the cost of searches through a multimedia repository is disclosed where the repository contains a plurality of objects having at least two different attributes such as color in a newspaper photograph and text in the subtitle. The method comprises selecting a ranking expression, translating the ranking expression into resulting filter conditions and then optimizing the resulting filter conditions to perform the search. A database look-up step is included which determines the cost of performing searches over the various subconditions of the filter condition. The least costly subcondition is searched first to retrieve objects from the multimedia repository. The remaining subconditions are then evaluated on the retrieved objects using either a search step or probe step depending upon the determined cost to perform each. A further database look-up step predicts a grade of match necessary in the translated ranking expression to retrieve at least the number of objects requested in the search.