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:
Mar. 31, 2009
Filed:
Sep. 30, 2005
Peter Jay Haas, San Jose, CA (US);
Volker Gerhard Markl, San Jose, CA (US);
Nimrod Megiddo, Palo Alto, CA (US);
Utkarsh Srivastava, Stanford, CA (US);
Peter Jay Haas, San Jose, CA (US);
Volker Gerhard Markl, San Jose, CA (US);
Nimrod Megiddo, Palo Alto, CA (US);
Utkarsh Srivastava, Stanford, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A novel method is employed for collecting optimizer statistics for optimizing database queries by gathering feedback from the query execution engine about the observed cardinality of predicates and constructing and maintaining multidimensional histograms. This makes use of the correlation between data columns without employing an inefficient data scan. The maximum entropy principle is used to approximate the true data distribution by a histogram distribution that is as 'simple' as possible while being consistent with the observed predicate cardinalities. Changes in the underlying data are readily adapted to, automatically detecting and eliminating inconsistent feedback information in an efficient manner. The size of the histogram is controlled by retaining only the most 'important' feedback.