Index key range estimator
US4774657A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1986 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Jun 6, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99932
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A key estimator estimates the number of keys over a key range defined by key endpoints in an index to a data space. The number of keys in the key range required to be processed for a particular operation is estimated as a function of the number of pages referenced during a range level limited search. Two keys defining range endpoint keys are searched down to their lowest level in the tree. The level limit is then calculated as a function of desired granularity or accuracy of the estimate. The entire range of keys in the desired key range is then searched down to the level limit and the number of pages referenced during the search is counted and multiplied by an average key density per page to calculate the number of keys in the range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.