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:
Jul. 31, 2012
Filed:
Nov. 25, 2008
Yu Xu, San Diego, CA (US);
Olli Pekka Kostamaa, Santa Monica, CA (US);
Yu Xu, San Diego, CA (US);
Olli Pekka Kostamaa, Santa Monica, CA (US);
Teradata US, Inc., Dayton, OH (US);
Abstract
A system, method, and computer-readable medium for optimization of query processing in a parallel processing system are provided. Skewed values and non-skewed values are treated differently to improve upon conventional DISTINCT and aggregation query processing. Skewed attribute values on which a DISTINCT selection or group by aggregation is applied are allocated entries in a hash table. In this manner, a processing module may consult the hash table to determine if a skewed attribute value has been encountered during the query processing in a manner that precludes repetitive redistribution of rows with highly skewed attribute values on which a DISTINCT selection or group by aggregation is applied.