Method for choosing optimal query execution plan for multiple defined equivalent query expressions
US6598044B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2002 |
| Grant date | Jul 22, 2003 |
| Priority date | — |
| Expiry date | Jun 25, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99933
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A query formulates choices of multiple equivalent forms. A choice is represented by a CHOOSE operator having multiple arguments representing the equivalent forms. A lookup table is generated to include a group for each node other than CHOOSE arguments. For CHOOSE arguments, the generated table includes a single equivalence group having all choose arguments as members. The enumeration algorithm of the optimizer is applied to generate additional members and/or groups, whereby for each group, every member thereof is an equivalent. A cost value is assigned to each member of each group and a member of each group is selected as a lowest cost value member. The lowest cost value members of the groups define an optimized tree and optimization of the query.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.