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

By: Peter Moore

Peter Moore — Tue, 15 Feb 2011 17:07:35 +0000

Following up my previous comment, see MOS/Metalink note [ID 1071391.1] which confirms that in 10g and 11g FLASHBACK DATABASE does not appear in V$SESSION_LONGOPS. The note recommends querying V$DATAFILE_HEADER to trace progress…

By: Peter Moore

Peter Moore — Tue, 15 Feb 2011 16:47:43 +0000

I have to disagree about FLASHBACK DATABASE being visible in V$SESSION_LONGOPS. I do this on a regular basis on our 10.2.0.4 databases, and neither the Flashback phase, nor the media recovery phase show up in session_longops.

See below for paste from two concurrent sessions:

1. rman target /

Recovery Manager: Release 10.2.0.4.0 – Production on Mon May 2 11:32:22 2011

connected to target database: PRJ001D (DBID=1045557503, not open)

RMAN> flashback database to restore point PR2011_PRE_TIMERAVEL;

Starting flashback at 02-MAY-11
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=1980 devtype=DISK
allocated channel: ORA_DISK_2
channel ORA_DISK_2: sid=1979 devtype=DISK
allocated channel: ORA_DISK_3
channel ORA_DISK_3: sid=1978 devtype=DISK
allocated channel: ORA_DISK_4
channel ORA_DISK_4: sid=1977 devtype=DISK

starting media recovery

This has been running for several hours.

On another session:

sqlplus “/ as sysdba”

SQL*Plus: Release 10.2.0.4.0 – Production on Mon May 2 16:46:36 2011

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 – 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

16:46:36 SYS @ PRJ001D1 AS SYSDBA> select * from v$session_longops;

no rows selected

Elapsed: 00:00:00.01

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

[...] Araujo-Questions you always wanted to ask about Flashback Database… Leave a [...]

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