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:
Feb. 25, 2020
Filed:
Dec. 01, 2014
Nec Corporation, Minato-ku, Tokyo, JP;
Ting Chen, Tokyo, JP;
Kazuyo Narita, Tokyo, JP;
NEC CORPORATION, Tokyo, JP;
Abstract
To reduce the overall computation time of a batch of queries, multiple query optimization in SQL-on-Hadoop systems groups multiple MapReduce jobs converted from queries into a single one, thus avoiding redundant computations by taking sharing opportunities of data scan, map function and map output. SQL-on-Hadoop converts a query into a DAG of MapReduce jobs and each map function is a part of query plan composed of a sequence of relational operators. As each map function is a part of query plan which is usually complex and heavy, disclosed method creates a cost model to simulate the computation time which takes both I/O cost for reading/writing input file and intermediate data and CPU cost for the computation of map function into consideration. A heuristic algorithm is disclosed to find near-optimal integrated query plan for each group based on an observation that each query plan is locally optimal.