Database point-in-time restore and as-of query

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 pag...

Full description

Saved in:
Bibliographic Details
Main Authors DHAMANKAR ROBIN DHANANJAY, TALIUS TOMAS, KODAVALLA HANUMANTHA R
Format Patent
LanguageEnglish
Published 03.09.2013
Subjects
CALCULATING
COMPUTING
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
PHYSICS
Online AccessGet full text

Cover

More Information
Summary: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.
Bibliography:Application Number: US201213370125