Using shared dictionaries on join columns to improve performance of joins in relational databases
US10678791B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 2017 |
| Grant date | Jun 9, 2020 |
| Priority date | — |
| Expiry date | Oct 1, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/9535
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.