Method and apparatus for improving performance of approximate string queries using variable length high-quality grams

US7996369B2 · kind B2 · utility

Assignee

• The Regents of the University of California · US

Inventors

• Chen Li · Zhunan Town, TW
• Bin Wang · Orem, US
• Xaochun Yang · Shenyang, CN
• Alexander Behm · Lafayette, US
• Shengyue Ji · Irvine, US
• Jiaheng Lu · Beijing, CN

Key dates

• Filing date: Dec 14, 2008
• Grant date: Aug 9, 2011
• Expiry date: Dec 3, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F16/90344
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A computer process, called VGRAM, improves the performance of these string search algorithms in computers by using a carefully chosen dictionary of variable-length grams based on their frequencies in the string collection. A dynamic programming algorithm for computing a tight lower bound on the number of common grams shared by two similar strings in order to improve query performance is disclosed. A method for automatically computing a dictionary of high-quality grams for a workload of queries. Improvement on query performance is achieved by these techniques by a cost-based quantitative approach to deciding good grams for approximate string queries. An approach for answering approximate queries efficiently based on discarding gram lists, and another is based on combining correlated lists. An indexing structure is reduced to a given amount of space, while retaining efficient query processing by using algorithms in a computer based on discarding gram lists and combining correlated lists.