Method, system, and program for selecting a join order for tables subject to a join operation
US6980981B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2002 |
| Grant date | Dec 27, 2005 |
| Priority date | — |
| Expiry date | Apr 10, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99943
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Provided are a method, system, and program for selecting a join order for tables subject to a join operation. An estimation is made of a join cost to perform joins on permutations of at least two of the tables, wherein each join permutation indicates an order of joining the tables. A determination is made as to whether sufficient computational resources are available to perform a join cost analysis of further join permutations of the tables. If sufficient computational resources are not available, then a determination is made of a restricted subset of remaining join permutations of at least two of the tables for which join costs have not been estimated that is less than all the remaining join permutations. The join costs of permutations of tables in the restricted subset is estimated and the estimated join costs are used to select one join permutation of all the tables having a lowest estimated join cost.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.