Section 16.5. Flashback


16.5. Flashback

Oracle 10g introduced a wonderful set of features collectively referred to as flashback. Some use the flash recovery area that was discussed in the architecture section, and others use the new recycle bin or the undo tablespace. Where physical backups (the focus of this chapter) are mainly designed to recover from equipment and disk failures, flashback offers a number of interesting ways to recover from human error. Here is a quick summary of these features. Be sure to consult your documentation on how to use flashback.


Flashback query

This allows a user to query data at a previous point in time in order to reconstruct data that was lost or deleted by accident. The data needed for this feature is stored in the undo tablespace.


Flashback version query

Allows a DBA to view changes to the rows of a table over time. The data needed for this feature is stored in the undo tablespace.


Flashback transaction query

Allows a DBA to view changes to the database at the transactional level. The data needed for this feature is stored in the undo tablespace.


Flashback database

This is a CDP-style recovery of Oracle. It allows you to simply roll Oracle back in time to just before a major logical corruption error happened, such as the drop of a table. The data needed for this feature is stored in the flash recovery area.


Flashback table

Allows the DBA to recover a table to an earlier point in time. The data needed for this feature is stored in the undo tablespace.


Flashback drop

Provides "undrop" protection when dropping tables in Oracle. The data needed for this feature is stored in the Oracle recycle bin.

16.5.1. Other Commercial Backup Methods

There is at least one commercial backup tool that backs up Oracle databases without using rman. It uses the same tools your scripts would use (e.g., begin backup/end backup), so it suffers many of the same limitations that such scripts would have. One such product is BMC's SQL Backtrack. Originally designed for Sybase, this product has been ported to Oracle, Informix, and SQL Server. At this writing, SQL Backtrack does not do volume management. It can, however, interface with some commercial storage managers, allowing them to provide volume management.




Backup & Recovery
Backup & Recovery: Inexpensive Backup Solutions for Open Systems
ISBN: 0596102461
EAN: 2147483647
Year: 2006
Pages: 237

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