Flashback Database question

I have a question about the contents of flashback logs used in Flashback Database. Oracle documentation says Flashback Logs contain 'before images' of the blocks to undo changes to a point in time just before a specified target time or SCN. Does this make flashback logs similair to blocks in Undo Segments.
Also, in some books notably one Oracle Press book for OCA (1z0-042) preparation written by Damir Bersinic, it is mentioned that flashback logs contain 'altered blocks' rather than "images of blocks before the change" mentioned in Oracle Docs. If it is 'altered blocks', then that would make flash logs similair to redo logs. which one is right?

I would agree and go with Oracle Documentation (for obvious reasons..right!). Flashback logs contains 'before images"....and you are right then it would be similar to undo changes, but undo changes are not retained are preserved for whole lot of time right? so as to allow you to go to a point in time in the past. I am sure there would be differences in how the before images in flashback logs are stored than that of undo.
Thanks
Chandra Pabba

Similar Messages

A new question on how to Enable Flashback Database on the standby database?

Best Practice document said:
Enable Flashback Database on the standby database to minimize downtime for logical corruptions.
I would like to know where to find document or anybody already had experience for this topic?
Also I would like to know what is the best practice for backup/recovery of the Physcial standby database?
Thanks in advance.

Hello;
Just an opinion but I like the book "Oracle Data Guard 11g Handbook" as both the document and the answers to the second question.
Chapter 12 covers the A to Z of RMAN with Data Guard.
This book sold me on Flashback since Flashback allows a former Primary database to be reinstated after a failover operation with being restored ( provided sufficient flashback logs are available)
My own experience is I tried a failover test without it and trash my test Primary.
I did a simple failover test a few weeks ago, here are my notes.
http://www.visi.com/~mseberg/Data_Guard_Failover_Test_using_SQL.pdf
Best Regards
mseberg

Basic question about Flashback Database

Hi,
I have a very generic question about using Flashback Database.
On my testing systems, for performance testing and simulation purposes, I want to create a guaranteed restore point so I can test impact on batch when code change releases are done, before deployment in production. My confusion is with respect to redo logs, as summarized in the questions below:
1. Is it possible to change redo log files, when a guaranteed restore point has been configured?
2. If yes, will the Flashback to restore point, also change the size of the redo logs?
I could not find anything in the docs about this....hence my question....
Appreciate your time taken in responding to these questions....
Regards.

HI,
donneskold wrote:
Hi,
I have a very generic question about using Flashback Database.
On my testing systems, for performance testing and simulation purposes, I want to create a guaranteed restore point so I can test impact on batch when code change releases are done, before deployment in production. My confusion is with respect to redo logs, as summarized in the questions below:
1. Is it possible to change redo log files, when a guaranteed restore point has been configured?
1) Yes it is possible.
2. If yes, will the Flashback to restore point, also change the size of the redo logs?
2) It will not change the size of redo log file. Cannot resize a redo log file..
I could not find anything in the docs about this....hence my question....
Appreciate your time taken in responding to these questions....
Regards.
Thank you

Flashback Database on Data Guard setup

Hello!
Win 2003 server - 64 bit
Oracle 10.2.0.4
As i have noticed Flashback Database is popular in Data Guard setups for the reinstate reason; you dont need to rebuild.
However, im looking at Flashback for 'flashback database' reasons. Some developers has asked for a method to rollback if an release has gone bad, so my questions is;
If i flashback database primary database, will standby also change due to redo log shipment?
Thank u!

After flashing primary database check CURRENT_SCN in Standby. If flashback scn is greater then current_scn, then do nothing. Otherwise, on standby:
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
FLASHBACK STANDBY DATABASE TO SCN "flashback_scn_number -1";
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

After Flashback database can I use my backups?

I performed a flashback database and then opened the database with
alter database open resetlogs;
Now when I try the following command in rman I get this message:
RMAN> list backup
2> ;
new incarnation of database registered in recovery catalog
starting full resync of recovery catalog
full resync complete
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
435 Incr 1 9.36M DISK 00:00:11 30-AUG-09
BP Key: 440 Status: AVAILABLE Compressed: NO Tag: TAG20090830T170015
All the backups are still there but it tells me a new incarnation of the database has been registered in the recovery catalog.
My question is: Do I need to do anything different from now on? Also can my existing backups still be used if needed?
thanks in advance,
Richard

For u question ist take a rman backup.
RMAN> backup database;
Starting backup at 31-AUG-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=140 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSTEM01.DBF
input datafile fno=00003 name=F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSAUX01.DBF
input datafile fno=00005 name=F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\EXAMPLE01.DBF
input datafile fno=00002 name=F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF
input datafile fno=00004 name=F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\USERS01.DBF
channel ORA_DISK_1: starting piece 1 at 31-AUG-09
channel ORA_DISK_1: finished piece 1 at 31-AUG-09
piece handle=F:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2009_08_31\O1_MF_NNNDF_TAG20090831T131520_59PY48QX_.BKP tag=TAG20090831T131520 comment=
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 31-AUG-09
channel ORA_DISK_1: finished piece 1 at 31-AUG-09
piece handle=F:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2009_08_31\O1_MF_NCSNF_TAG20090831T131520_59PY5R4D_.BKP tag=TAG20090831T131520 comment=
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04
Finished backup at 31-AUG-09
After that …..
SQL> create table y (id number);
Table created.
SQL> select to_char(sysdate,'dd-mm-yy hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'
31-08-09 13:23:03
SQL> drop table y
2 ;
Table dropped.
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 612368384 bytes
Fixed Size 1250428 bytes
Variable Size 226495364 bytes
Database Buffers 377487360 bytes
Redo Buffers 7135232 bytes
Database mounted.
SQL> flashback database to timestamp to_timestamp('31-08-09 13:23:03','dd-mm-yy hh24:mi:ss');
Flashback complete.
SQL> alter database open resetlogs;
Database altered.
SQL> desc y
Name Null? Type
ID NUMBER
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 612368384 bytes
Fixed Size 1250428 bytes
Variable Size 226495364 bytes
Database Buffers 377487360 bytes
Redo Buffers 7135232 bytes
Database mounted.
SQL> select name from v$datafile;
NAME
F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSTEM01.DBF
F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF
F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSAUX01.DBF
F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\USERS01.DBF
F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\EXAMPLE01.DBF
SQL> host del F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\USERS01.DBF
SQL> alter database open;
alter database open
ERROR at line 1:
ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
ORA-01110: data file 4: 'F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\USERS01.DBF'
Then I restore old backup from rman
RMAN> restore database;
Starting restore at 31-AUG-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=154 devtype=DISK
channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSTEM01.DBF
restoring datafile 00002 to F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\UNDOTBS01.DBF
restoring datafile 00003 to F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\SYSAUX01.DBF
restoring datafile 00004 to F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\USERS01.DBF
restoring datafile 00005 to F:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\EXAMPLE01.DBF
channel ORA_DISK_1: reading from backup piece F:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2009_08_31\O1_MF_NNNDF_TAG20090831T131520_59PY48QX_.BK
channel ORA_DISK_1: restored backup piece 1
piece handle=F:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2009_08_31\O1_MF_NNNDF_TAG20090831T131520_59PY48QX_.BKP tag=TAG20090831T131520
channel ORA_DISK_1: restore complete, elapsed time: 00:00:46
Finished restore at 31-AUG-09
RMAN> recover database;
Starting recover at 31-AUG-09
using channel ORA_DISK_1
starting media recovery
archive log thread 1 sequence 22 is already on disk as file F:\ORACLE\PRODUCT\10.2.0\ARC\ARC00022_0693947048.001
archive log thread 1 sequence 23 is already on disk as file F:\ORACLE\PRODUCT\10.2.0\ARC\ARC00023_0693947048.001
archive log filename=F:\ORACLE\PRODUCT\10.2.0\ARC\ARC00022_0693947048.001 thread=1 sequence=22
archive log filename=F:\ORACLE\PRODUCT\10.2.0\ARC\ARC00023_0693947048.001 thread=1 sequence=23
media recovery complete, elapsed time: 00:00:06
Finished recover at 31-AUG-09
Then I back sqlplus
SQL> alter database open;
Database altered.
SQL> desc y
Name Null? Type
ID NUMBER
So answer your question is , YES you can restore from you old backup , not need to do anything else.
Regards
Liakat hossain

Alternatives to FLASHBACK database

We're getting ready to upgrade to 11gR2, and so I thought I'd ask the question just in case there was something new ...
Are there alternatives to FLASHBACK DATABASE in order to rollback DDL? I was hoping that there was a new feature that I'm just not aware of, which allows for the same functionality at a smaller level, like at the schema level. I'm assuming we're not there yet based on the searches I've been performing this morning, but I thought I'd ask.
Thanks,
--=Chuck

Chuck, since you asked this question in relation to an upgrade I will mention that Oracle does provide a downgrade procedure; however 11.2 is a well tested environment and any problems you encounter you should be able either tune, patch, or otherwise workaround.
I have never consider flashback database a useful feature. There is no way we could ever flash back production because the DML often reflects real world actions such as shipping material out of the plant. If it was shipped we need to bill for it. If someone messes up that area of the applicaiton has to be fixed and the data corrected without any direct changes being made to the data in the uneffected portions of the system. Someone might mention flashing the database back, extracting what you need, flashing back forward but if the database is up there are users and data is being changed. We could never do it and I do not know too many other DBA's who could realistically use the feature except in test.
HTH -- Mark D Powell --

How to use Flash recovery area only for flashback database feature

I would like to use flash recovery area only for flashback database feature, which means, flash recovery area will store only flashback logs.
I dont want to use that file system for any other files, like archive log files, database backups, control file copies, multiplex redo log, etc
is it possible? I want to use this feature only for flashback database option and hence i dont want to disturb any existing configuration in my database
including backup jobs. Is it required to store archive redo log files also in flash recovery area to use the flashback database feature?
I certainly can't afford to have a copy of entire database in this file system as size of my DB is more than the flash recovery area file system I have.
Thanks
Sarayu

user13312943 wrote:
Aman,
I think i was not clear in my question. Let me try again
My only requirement is to use flashback database feature (or be prepared to use if required). I dont want to create a large file system to use this FRA to store all these files. Out of all the files being stored here copy of data files seems to be consuming more space. I see these files are classified as transient and permanent files. I am okay with permanent files. I fear that this file system may consume more space if i store backup files on disk. I want database backups to go to tapes, not to the FRA disk. Is it possible?
Thanks for your reply
Okay, well in that case you can use RMAN and push the backups to the tape drives. FLB logs would be stored on the FRA.
Aman....

FLASHBACK Database : rman vs sql command differnces

I am new to Oracle and want understand the difference and which is the correct way of flashing back the database?
RMAN command vs SQL Command on using FLASHBACK DATABASE
SQL> FLASHBACK DATABASE TO RESTORE POINT BEFORE_ONLINE_TEST; {CODE} Vs rman> run{
     flashback database to restore point BEFORE_TEST_320130313;
     sql "alter database open resetlogs"; }
Referring this article on http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmflash.htm#BGBDCAFA it says we can use both RMAN and SQL command for database flashback.
Questions:
1. Difference between using RMAN and SQL command on database flashback?
2. When to use RMAN or SQL on the database flashback?
3. Which is the Oracle recommended or best way ?
Edited by: Sivaprasad S on Mar 15, 2013 7:26 PM
Edited by: Sivaprasad S on Mar 15, 2013 7:26 PM
Edited by: Sivaprasad S on Mar 15, 2013 7:27 PM
Edited by: Sivaprasad S on Mar 15, 2013 7:27 PM
Edited by: Sivaprasad S on Mar 15, 2013 7:28 PM
Edited by: Sivaprasad S on Mar 15, 2013 7:29 PM

When I issue the SQL Plus command of
SQL> flashback database to restore point BEFORE_TEST_20130313 ;
flashback database to restore point BEFORE_TEST_20130313
ERROR at line 1:
ORA-38754: FLASHBACK DATABASE not started; required redo log is not available
ORA-38762: redo logs needed for SCN 87612483975 to SCN 87612485856
ORA-38761: redo log sequence 1 in thread 1, incarnation 3 could not be accessedHowever on running this on RMAN
RMAN>
list backup of archivelog scn between 87612483975 and 87612485856
RMAN> ;
starting full resync of recovery catalog
full resync complete
List of Backup Sets
===================
BS Key Size       Device Type Elapsed Time Completion Time
5212758 19.75M     SBT_TAPE    00:00:04     13-MAR-2013 16:36:17
        BP Key: 5212765   Status: AVAILABLE Compressed: NO Tag: TAG20130313T163611
        Handle: <TestDB_60:809973373:1>.al   Media: 945c30b6:506c6cd2:3a14:0001
List of Archived Logs in backup set 5212758
Thrd Seq     Low SCN    Low Time             Next SCN   Next Time
1    1       87612468290 13-MAR-2013 13:28:19 87612484321 13-MAR-2013 16:36:06
1    2       87612484321 13-MAR-2013 16:36:06 87612484339 13-MAR-2013 16:36:09
BS Key Size       Device Type Elapsed Time Completion Time
5212759 896.50M    SBT_TAPE    00:00:17     13-MAR-2013 16:36:30
        BP Key: 5212766   Status: AVAILABLE Compressed: NO Tag: TAG20130313T163611
        Handle: <TestDB_59:809973373:1>.al   Media: 945c30b6:506c6cbd:39f5:0001
List of Archived Logs in backup set 5212759
Thrd Seq     Low SCN    Low Time             Next SCN   Next Time
1    5       87612363812 12-MAR-2013 14:22:26 87612659040 13-MAR-2013 03:04:08
run {
allocate CHANNEL dev_2 TYPE 'SBT_TAPE' format '%U' PARMS 'SBT_LIBRARY=/opt/omni/lib/libob2oracle8_64bit.so,ENV=(OB2BARTYPE=Oracle8)';
allocate CHANNEL dev_3 TYPE 'SBT_TAPE' format '%U' PARMS 'SBT_LIBRARY=/opt/omni/lib/libob2oracle8_64bit.so,ENV=(OB2BARTYPE=Oracle8)';
allocate CHANNEL dev_4 TYPE 'SBT_TAPE' format '%U' PARMS 'SBT_LIBRARY=/opt/omni/lib/libob2oracle8_64bit.so,ENV=(OB2BARTYPE=Oracle8)';
flashback database to restore point BEFORE_TEST_20130313;
sql "alter database open resetlogs";
release channel dev_2;
release channel dev_3;
release channel dev_4;
starting media recovery
archived log for thread 1 with sequence 2 is already on disk as file +DG_PERF_FLASH_02/TestDB/archivelog/2013_03_14/thread_1_seq_2.3612.810054205
archived log for thread 1 with sequence 3 is already on disk as file +DG_PERF_FLASH_02/TestDB/archivelog/2013_03_14/thread_1_seq_3.1588.810054205
channel dev_2: starting archived log restore to default destination
channel dev_2: restoring archived log
archived log thread=1 sequence=1
channel dev_2: reading from backup piece <TestDB_60:809973373:1>.al
channel dev_2: piece handle=<TestDB_60:809973373:1>.al tag=TAG20130313T163611
channel dev_2: restored backup piece 1
channel dev_2: restore complete, elapsed time: 00:00:46
channel dev_2: deleting archived log(s)
archived log file name=+DG_PERF_FLASH_02/TestDB/archivelog/2013_03_15/thread_1_seq_1.2969.810106317 RECID=49 STAMP=810106318
media recovery complete, elapsed time: 00:00:05
Finished flashback at 10-MAR-2013 05:32:07
database reset to incarnation 5215723
When we issue the SQL Plus command, if there is need of old database backup of archive log, how does that SQL Plus communicate with rman recovery catalog and retrieve?

Deleted guarantee restroe point (flashback database)?

Hi!
User create restore "guarantee" restore point like:
create restore point full_restore guarantee flashback database;By mistake he/her delete all flashback content. Database is shutdowned.
After trying to open, there is a know problem with flashback restore point.
All around the internet there is a hint like:
startup mount;
alter database flashback off;
alter database flashback on;
alter database open resetlogs;But here is a problem with "guarantee" restore point which doesn't allow to open the database without having flashback files that will ensure "guarantee restore point".
Oracle will rather die then not to ensure "guarantee" statement!!! All looks that this is a dead end situation!
My question is : What to do in such a situation if you do not have backup ed flashback area and content is somehow lost.
This lead to very interesting question: How danger is "guaranteed restore point" in such a cases?
Any hint or comments more then welcome.
THX
Sorry if this is not right group for asking about flashback....

'Flashback database' is a nice feature, but you should never rely on it entirely. If you've lost your flashback logs and NO regular backups are available, in case of a media crash, you are in a bad situation, because you cannot restore/recover,
Werner

Use of Flashback Database in Data guard environments

11.2.0.3/RHEL 5.8
I've come across several docs which talk about configuring FLASHBACK DATABASE in dataguard environments. We have several
Physical standby DBs (Single Instance & RAC) running in our shop.I would like to know two or three major(common) use of FLASHBACK DATABASE in data guard environments.
I understood one use mentioned in the below URL ie. recovering from a logical mistake
http://uhesse.com/2010/08/06/using-flashback-in-a-data-guard-environment/
I would like to know what are the other major/common use of Flashback Database feauture in DataGuard environment

A couple of other uses:
1) You can use flashback to test your DR. So you can activate your standby. Test application/network connectivity and functionality on your DR site and when done revert this database back to a physical standby. You do however have to ensure that this is allowed in your environment. In some places I have worked this would be a big no no as there were zero data loss requirements. However some companies will allow this as long as the standby is back in place within a certain time period.
2) In the case that you have to do a failover for whatever reason, but then what was the primary site becomes available, you can flashback what was your primary to make it the standby rather than re-instatiating the database from scratch.
Eg. You have a power outage at your primary site so you perform a failover and your standby becomes the primary. Once what was your primary site is back online, you can convert your previous primary into a standby by doing a full back/restore (or whatever method you choose) to recreate your standby again. However you also have the option of using flashback on this database and then convert it into a standby as this would potentially be quicker than re-instantiating the standby.

Can I use flashback database to flashback a pluggable database?

Hi All,
I created a container database and then created a pluggable database.
In the pluggable 12.1 datbase, I loaded the user data.
I performed the below
sqlplus / as sysdba;
create restore point CLEAN_DB guarantee flashback database;
And I performed the transactions on the pdb.
Now my intention is to restore to the restore point CLEAN_DB as created from the above step.
If I perform the below, will it restore my pdb to the initial state?
flashback database to restore point CLEAN_DB;
Regards,
Kamal.

Hi,
You cannot use FLASHBACK DATABASE for pluggable database.
Flashback query/versions queryis UNDO based and work in PDB’s
Flashback transaction query/flashback transactionis UNDO and REDO based and work in PDB’s
Flashback data archiveUNDO gernerated archives
Flashback table
before drop –> Rename segment name of recylebin, which is based on UNDO, work in PDB’s
flashback table to –> is UNDO based, work in PDB’s
Flashback databasedoesn’t work in PDB’s:
RMAN> flashback pluggable database prmdb01 to time "to_date('23:00 20-11-2013','hh24:mi dd-mm-yyyy')";
Starting flashback at 25-NOV-13
using channel ORA_DISK_1
using channel ORA_DISK_2
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of flashback command at 11/20/2013 23:00:00
RMAN-05108: Command is not supported for pluggable database
Regards
Mahir M. Quluzade
p.s. Command exists but not supporting, may be next release come support.

Can I use flashback database to recover it?-----QNo.115

I have dropped a tablespace through RESETLOGS.
Can I use flashback database to recover it?-----

5.3.1 Limitations of Flashback Database
http://download-east.oracle.com/docs/cd/B19306_01/backup.102/b14192/rpfbdb003.htm

Enabling flashback database adds unsupported spfile parameter

After enabling the flashback database I saw a new policy violation upon restart.
awrflush_threshold_metrics was set to true and added to the spfile. When I look that up, I get various dire warnings about using it.
If it's not supported, why does Oracle do this by default upon enabling the flashback database? And, is it necessary for the flashback database to work, or can I remove it?

What's your OS and DB versions?
Since 10g R2 this parameter Enables/Disables Flushing AWR Workload Metrics.
You should not set this hidden parameter unless directed by Oracle Support. All parameters that start with underscore (_) are considered internal and unsupported, which means that only Oracle is authorized to set them.
~ Madrid

Can we rollback catcpu.sql using flashback database?

Hello all,
Can we use FLASHBACK DATABASE to roll back the changes made by the catcpu.sql/catpatch.sql used for upgradation/patching? [ I am aware that oracle provides rollback sql's but just curious. ]
TIA,
JJ

Keep in mind, catpatch is only the second part of the patching process, before that you already patched the software. If you want to have a complete rollback, follow the instructions in the readme file.
Werner

Using Flashback Database on 11g

hi everyone,
My 11g db is size 50 GB on a very strong Windows server.
No performance problems whatsoever.
If I enable Flashback Database logging am I likely to notice any performance degradation? The data is not really heaviily changed.
What about disk space - does it use the existing redo/archive logs or does it create different logs for the flashback feature?
Thanks for your opinions.
John

user629010 wrote:
hi everyone,
My 11g db is size 50 GB on a very strong Windows server.
No performance problems whatsoever.
If I enable Flashback Database logging am I likely to notice any performance degradation? The data is not really heaviily changed.Even if the data is not heavily changed, with the internal changes happening, there would be some activity always generating Redo/Undo. You would want to check the working of the RVWR process to see any possible waits over it. In addition to this, if the speed of the writing of RVWR is not good enough to write, you would see the contention on the Undo tablespace as it won't be freed as long as the corresponding writes are not saved by RVWR.
>
What about disk space - does it use the existing redo/archive logs or does it create different logs for the flashback feature?Flashback database uses *.flb* files which , if I remember correctly ,grow in 8mb of chunks. FLasback database does not uses the existing redo logs. Yes, it does uses the archived logs in addition to the FLB logs. So before you think to use this featuture, you do want to check the retention period of the logs , also the disk space required to manage that much retention period.
HTH
Aman....
Thanks for your opinions.
John

Flashback Database question

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