Abstract: Disclosed is a multi-dimensional selectivity estimation method using compressed histogram information which the database query optimizer in a database management system uses to find the most efficient execution plan among all possible plans. The method includes the several steps to generate a large number of small-sized multi-dimensional histogram buckets, sampling DCT coefficients which have high values with high probability, compressing information from the multi-dimensional histogram buckets using a multi-dimensional discrete cosine transform(DCT) and storing compressed information, and estimating the query selectivity by using compressed and stored histogram information as the statistics.
Type:
Grant
Filed:
March 19, 1999
Date of Patent:
October 30, 2001
Assignee:
Korea Advanced Institute of Science and Technology
Inventors:
Ju-Hong Lee, Deok-Hwan Kim, Chin-Wan Chung