System, method, and program for using duplicated direct pointer sets in keyed database records to enhance data recoverability without logging
US5881379A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1996 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | May 20, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The system, method, and program product of this invention allows a database management system to internally use direct and indirect pointing to locate targeted data elements that are logically related to another data element or are a target of a secondary index. By using direct and indirect pointing, the number of steps involved in a reorganization of the database can be reduced. After a reorganization, the database management system does not go back, in a separate process, to update all of the direct pointers that have pointed to segments that have moved as a result of the reorganization. Instead, the direct pointer is updated, by using the indirect pointer, only upon a first reference to the targeted data element that has moved. Each targeted data element has an entry in an indirect index where a unique identifier of the targeted data element is the key into the index. The indirect index has two direct pointer slots. Which pointer slot is used by the DBMS is determined by the odd/even reorganization number. For each reorganization, the DBMS alternates between the two portions of the indirect index to update the appropriate one of the two pointers with a new location whenever the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.