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. 13, 2021
Filed:
Feb. 22, 2019
Hitachi, Ltd., Tokyo, JP;
The University of Tokyo, Tokyo, JP;
Yuya Isoda, Tokyo, JP;
Kazuhiko Mogi, Tokyo, JP;
Kouji Kimura, Tokyo, JP;
Kazuo Goda, Tokyo, JP;
Yuto Hayamizu, Tokyo, JP;
Masaru Kitsuregawa, Tokyo, JP;
HITACHI, LTD., Tokyo, JP;
THE UNIVERSITY OF TOKYO, Tokyo, JP;
Abstract
If a query indicates joining of N (N is an integer of no less than 3) relation tables, a database management system calculates a query cost that is based on a power consumption amount for query execution, for each of a first query plan candidate in which a temporary table is generated and the temporary table is stored in a storage device unit with a first access cost, a second query plan candidate in which a temporary table is generated and the temporary table is stored in a storage device unit with a second access cost that is higher than the first access cost and a third query plan candidate in which the N relation tables are joined in a pipelined manner without generation of a temporary table, selects a relatively low-query cost query plan candidate and executes the query based on the query plan candidate.