System, method, and computer-readable medium for optimization of multiple parallel join operations on skewed data
US8195644B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 6, 2008 |
| Grant date | Jun 5, 2012 |
| Priority date | — |
| Expiry date | Nov 15, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/2456
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system, method, and computer-readable medium that facilitate management of data skew during a parallel multiple join operation are provided. Portions of tables involved in the join operation are distributed among a plurality of processing modules, and each of the processing modules is provided with a list of skewed values of a join column of a larger table involved in the join operation. Each of the processing modules scans the rows of first and second tables distributed to the processing modules and compares values of the join columns of both tables with the list of skewed values. Rows of a larger table having non-skewed values in the join column are redistributed, and rows of the larger table having skewed values in the join column are maintained locally at the processing modules. Rows of the smaller table that have non-skewed values in the join column are redistributed, and rows of the smaller table that have skewed values in the join column are duplicated among the processing modules. Rows of a third table involved in the join operation are redistributed based on the join attribute value of the rows. A local join data set is then generated by each of the processing modules, a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.