The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 10, 2008
Filed:
Jan. 15, 2004
Abdo Esmail Abdo, Rochester, MN (US);
Travis Michael Drucker, Rochester, MN (US);
Abdo Esmail Abdo, Rochester, MN (US);
Travis Michael Drucker, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Statistics for a pattern matching predicate are generated using stored character statistics. A first structure stores, for each of a plurality of character positions, frequently occurring characters in that character position, and a count of the number of occurrences of that character. A second structure stores frequently occurring characters that are subsequent to the frequently occurring characters stored in the first structure, and a probability of occurrence of each frequently occurring subsequent character. To form an estimate of the number of tuples matching a pattern matching predicate, statistics are retrieved for the matching characters in each matching position in the predicate, and then combined to produce the estimate. In the event a statistic is not stored for a desired character, the available statistics are used to make an estimate by accumulating statistics for other characters, and then calculating average frequency of occurrence of characters that do not have stored statistics.