Invention Grant
US08688682B2 Query expression evaluation using sample based projected selectivity
失效
使用基于样本的投影选择性进行查询表达式评估
- Patent Title: Query expression evaluation using sample based projected selectivity
- Patent Title (中): 使用基于样本的投影选择性进行查询表达式评估
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Application No.: US11690156Application Date: 2007-03-23
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Publication No.: US08688682B2Publication Date: 2014-04-01
- Inventor: Michael S. Faunce , Yasunobu Suginaka
- Applicant: Michael S. Faunce , Yasunobu Suginaka
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Biggers Kennedy Lenart Spraggins, LLP
- Main IPC: G06F17/30
- IPC: G06F17/30 ; G06F7/00

Abstract:
Methods, systems, and computer program products are provided for query expression evaluation for query optimization. Embodiments include receiving a query including a plurality of predicates; creating a truth table representing the possible solutions to the query; identifying a plurality of intersections of the truth table, the plurality of intersections including each predicate of the query; assigning a selectivity factor to each predicate; determining in dependence upon the selectivity factors for each predicate a selectivity rating for each of the intersections of the truth table; selecting one or more of the intersections in dependence upon the selectivity rating; and determining in dependence upon the selected intersections a percentage of rows in a database table returned by the query; and providing the percentage of rows in the database table to an access plan generator for query optimization.
Public/Granted literature
- US20080235181A1 Query Expression Evaluation Using Sample Based Projected Selectivity Public/Granted day:2008-09-25
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