Comments on: Questions you always wanted to ask about Flashback Database…

By: Fung-Chiao

Fung-Chiao — Sun, 22 Nov 2009 16:11:10 +0000

Hi André Araujo,

You have done a great job for clarify some of the questions that I have regarding flashback database. I do have another question: Is flashback log a physical file that will be created when we turn on flashback (How do we know which file name for flashback log in OS level)? What is the file format or it is a table that created in Oracle database?

Thanks,

Fung-Chiao

By: Andre Araujo

Andre Araujo — Tue, 10 Nov 2009 23:05:21 +0000

Surachart: You can also enable FORCE LOGGING for your database, if that’s appropriate.

By: Surachart Opun

Surachart Opun — Tue, 10 Nov 2009 18:38:21 +0000

Hi André Araujo,

Thank You for your reply… Good way, I think I should avoid NOLOGGING ;)

By: Blogroll Report 30/10/2009-06/11/2009 « Coskan’s Approach to Oracle

Blogroll Report 30/10/2009-06/11/2009 « Coskan’s Approach to Oracle — Tue, 10 Nov 2009 18:13:05 +0000

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By: André Araujo

André Araujo — Mon, 09 Nov 2009 23:45:07 +0000

@Surachart: Thanks, Surachart. When you have NOLOGGING operations going on on your database you can still use Flashback. However, if you flashback to a point-in-tmie *during* a NOLOGGING operation the blocks affected by the operation will be marked as logically corrupt. If the flashback time is *after* the NOLOGGING operation you’ll see the data *without* the rows affected by the operation. To ensure recoverability you should always backup the database after NOLOGGING operations.

@Emre: Thanks for your feeback, Emre.

By: Emre Baransel

Emre Baransel — Mon, 09 Nov 2009 08:17:11 +0000

Thank you for this helpful article.

By: Surachart Opun

Surachart Opun — Sat, 07 Nov 2009 18:47:10 +0000

Hi André Araujo,

Thank you for good stuff.
What happen, On flashback database with tablespace (nologging) state?

By: André Araujo

André Araujo — Sat, 07 Nov 2009 14:21:31 +0000

Hi, Michael,

Indeed that information is not totally accurate. ALTER DATABASE FLASHBACK ON is an online operation on 11g Release 2 (I haven’t tested in 11g Release 1 yet). In 10g it requires the database to be mounted.

I’ll rectify the post soon. Thanks for your feedback.

Cheers,
André

By: Michael Wehrle

Michael Wehrle — Fri, 06 Nov 2009 21:26:30 +0000

André Araujo, can you please clarify about question #2 about turning on Flashback while the database is open? I have just tried this on a 10.2.0.4.1 database, and received the ORA message “ALTER DATABASE FLASHBACK ON
*
ERROR at line 1:
ORA-01126: database must be mounted in this instance and not open in any instance”