Pre-image logging for database recovery
US7620660B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2005 |
| Grant date | Nov 17, 2009 |
| Priority date | — |
| Expiry date | May 9, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In order to provide recovery for a database stored on storage not meeting the WAL protocol requirements, for example, storage including a temporary cache and a second storage (e.g. an IDE disk with a temporary cache and a hard disk), a log is created including, for each changed page, a pre-image of the page before changes were effected. The log also includes one or more change log records logging changes made to the page. Periodic checkpoints occur in which the cached pages are flushed to the disk. Recovery proceeds with a redo pass through the active log and then with an undo pass, undoing any transactions that have not been committed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.