Virtual cursors for XML joins
US7685138B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 2005 |
| Grant date | Mar 23, 2010 |
| Priority date | — |
| Expiry date | Dec 30, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/8365
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system, method, and computer program product to improve XML query processing efficiency with virtual cursors. Structural joins are a fundamental operation in XML query processing, and substantial work exists on index-based algorithms for executing them. Two well-known index features—path indices and ancestor information—are combined in a novel way to replace at least some of the physical index cursors in a structural join with virtual cursors. The position of a virtual cursor is derived from the path and ancestor information of a physical cursor. Virtual cursors can be easily incorporated into existing structural join algorithms. By eliminating index I/O and the processing cost of handling physical inverted lists, virtual cursors can improve the performance of holistic path queries by an order of magnitude or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.