Invention Grant
- Patent Title: Subquery predicate generation to reduce processing in a multi-table join
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Application No.: US15471985Application Date: 2017-03-28
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Publication No.: US11036732B2Publication Date: 2021-06-15
- Inventor: Thomas A. Beavin , Andrei F. Lurie , Terence P. Purcell
- Applicant: International Business Machines Corporation
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Konrad Raynes Davda & Victor LLP
- Agent Janaki K. Davda
- Main IPC: G06F16/2453
- IPC: G06F16/2453

Abstract:
Provided are techniques for efficient subquery predicate generation to reduce processing in a multi-table join. It is determined that a query is to be rewritten, wherein the query includes a predicate for a first column of a first table and a second column of a second table. The query is rewritten with generated subquery predicates for the first table that are to be applied to the second table and with generated subquery predicates for the second table that are to be applied to the first table. Minimum and maximum ranges for columns of the generated subquery predicates at a cursor open are determined. The minimum and maximum ranges are merged to determine inclusive ranges that exist in the first table and the second table. The generated subquery predicates are rewritten as derived local subquery predicates with the inclusive ranges. The query with the derived local subquery predicates is executed.
Public/Granted literature
- US20180285415A1 SUBQUERY PREDICATE GENERATION TO REDUCE PROCESSING IN A MULTI-TABLE JOIN Public/Granted day:2018-10-04
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