The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 2013
Filed:
Feb. 09, 2012
Tomas Talius, Sammamish, WA (US);
Robin Dhananjay Dhamankar, Bellevue, WA (US);
Hanumantha R. Kodavalla, Sammamish, WA (US);
Tomas Talius, Sammamish, WA (US);
Robin Dhananjay Dhamankar, Bellevue, WA (US);
Hanumantha R. Kodavalla, Sammamish, WA (US);
Microsoft Corporation, Redmond, WA (US);
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.