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. 06, 2012
Filed:
May. 22, 2008
Yu Xu, San Diego, CA (US);
Pekka Kostamaa, Santa Monica, CA (US);
Yu Xu, San Diego, CA (US);
Pekka Kostamaa, Santa Monica, CA (US);
Teradata Corporation, Dayton, OH (US);
Abstract
A system, method, and computer-readable medium that facilitate management of data skew during a parallel join operation are provided. Portions of tables involved in the join operation are distributed among a plurality of processing modules, and each of the processing modules is provided with a list of skewed values of a join column of a larger table involved in the join operation. Each of the processing modules scans the rows of the tables distributed to the processing modules and compares values of the join columns of both tables with the list of skewed values. Rows of the larger table having non-skewed values in the join column are redistributed, and rows of the larger table having skewed values in the join column are maintained locally at the processing modules. Rows of the smaller table that have non-skewed values in the join column are redistributed, and rows of the smaller table that have skewed values in the join column are duplicated among the processing modules.