Invention Grant
- Patent Title: Using shared dictionaries on join columns to improve performance of joins in relational databases
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Application No.: US15602009Application Date: 2017-05-22
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Publication No.: US10678791B2Publication Date: 2020-06-09
- Inventor: Shasank K. Chavan , Dina Thomas , Ajit Mylavarapu , Prashant Gaharwar , Tirthankar Lahiri , Jesse Kamp
- Applicant: Oracle International Corporation
- Applicant Address: US CA Redwood Shores
- Assignee: Oracle International Corporation
- Current Assignee: Oracle International Corporation
- Current Assignee Address: US CA Redwood Shores
- Agency: Hickman Palermo Becker Bingham LLP
- Main IPC: G06F16/2453
- IPC: G06F16/2453 ; G06F16/22 ; G06F16/9535 ; G06F16/2455 ; G06F7/24

Abstract:
Techniques are described for encoding join columns that belong to the same domain with a common dictionary. The tables are encoded with dictionary indexes that make the comparison operation of a join query a quick equality check of two integers and there is no need to compute any hashes during execution. Additionally, the techniques described herein minimize the bloom filter creation and evaluation cost as well because the dictionary indexes serve as hash values into the bloom filter. If the bloom filter is as large as the range of dictionary indexes, then the filter is no longer a probabilistic structure and can be used to filter rows in the probe phase with full certainty without any significant overhead.
Public/Granted literature
- US20170255675A1 USING SHARED DICTIONARIES ON JOIN COLUMNS TO IMPROVE PERFORMANCE OF JOINS IN RELATIONAL DATABASES Public/Granted day:2017-09-07
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