Sort-merge band join optimization
US10635671B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 2017 |
| Grant date | Apr 28, 2020 |
| Priority date | — |
| Expiry date | Sep 18, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/24537
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques herein optimize sort-merge join method for a band join. In an embodiment, for a query comprising a query block specifying a join between a first table and a second table, a band join condition is detected between the first table and the second table. Once the band join condition in detected, an execution plan is generated and executed. The execution of the execution plan includes: for a first row of at least a subset of first sorted rows, scanning second rows from a set of second sorted rows, joining each of said second rows with said first row, and ceasing to scan when encountering a row from the second sorted rows that falls outside a bound of said band join condition. Techniques also include parallelizing a workload by overlapping the distribution of rows to the same slave process and computing cost and cardinality estimation for enhanced band join.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.