Database point-in-time restore and as-of query
US8527462B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 2012 |
| Grant date | Sep 3, 2013 |
| Priority date | — |
| Expiry date | Apr 14, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/128
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A database is queried as of any wall-clock time within a retention period, via undo that uses database snapshots and a list of page level modifications. The snapshot is user-identified, automatically generated, or extracted from a backup. The list is maintained in a transaction log by persisting page content before a page is re-used, persisting deleted rows before they are moved, persisting compensation log record undo information, and/or logging a full page. To rewind an entire database, the undo scans the transaction log in reverse LSN order and undoes all page modifications. Undo reverses reallocated pages, table truncation, and/or table deletion, as well as page-level modifications of a schema, metadata values, and/or system tables. An as-of query is handled using as-of page(s) from a sparse page file. If the sparse page file does not already contain the responsive page(s), they are created and added to it.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.