Executing nested subqueries of parallel table functions in the parallel single cursor model
US7451133B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 2004 |
| Grant date | Nov 11, 2008 |
| Priority date | — |
| Expiry date | Nov 21, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99936
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques are provided for processing a database statement that includes a table function capable of parallel execution, where the input of the table function is specified in a subquery. During compilation of the database statement, a global cursor is generated for the database statement. The global cursor includes a first plan component for executing the table function and a second plan component for generating input for the table function. A “dummy” cursor is then generated. When slaves execute the table function, they call the dummy cursor for input. When a slave calls the dummy cursor for input, the dummy cursor causes a context switch back to the global cursor, so that the second plan component within the first cursor generates the input for the slave.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.