RE: Which archive logs are required for flashing back to guaranteed restore point?
- From: Herring Dave - dherri <Dave.Herring@xxxxxxxxxx>
- To: "ftaheny@xxxxxxxxx" <ftaheny@xxxxxxxxx>, oracle-l-freelists <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 14 Aug 2012 14:50:56 +0000
Fergal,
This isn't a direct answer on determining exactly which archives are needed,
but I can share our experience under 10.2.0.2. We frequently ran into problems
with archives getting removed until we full automated the process, making sure
that the guaranteed restore point was created while the database was in mount
mode, immediately after enabling flashback on the database.
From flashback to new restore point, we do:
* startup mount, flashback, open resetlogs
* thru RMAN delete all archivelogs
* startup the db, turn flashback off, then shutdown -> this clears all
flashback logs
* startup mount, enable flashback, create guaranteed restore point, then open
the db.
HTH.
DAVID HERRING
DBA
Acxiom Corporation
EML dave.herring@xxxxxxxxxx
TEL 630.944.4762
MBL 630.430.5988
1501 Opus Pl, Downers Grove, IL 60515, USA
WWW.ACXIOM.COM
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Fergal Taheny
Sent: Friday, August 10, 2012 5:47 PM
To: oracle-l-freelists
Subject: Which archive logs are required for flashing back to guaranteed
restore point?
Hi,
Database Version: 10.2.0.4.0
OS: Solaris 10
We are using guaranteed restore points without enabling full flashback database
logging.
I'm trying to flashback a database to a guaranteed restore point. It is failing
because it needs an archivelog which has been deleted.
I understand there is nothing I can do about this but this has happened a
couple of times so I would like to bullet proof way to avoid it.
The archive log oracle is looking for is actually older that the restore point.
i.e. the scn of the restore point is 18116228292 and the next_change# of the
archivelog that oracle is looking for is 18116218687. I have archivelog 2635
and all the later archivelogs but I don't have 2634. See below:
select name,SCN,DATABASE_INCARNATION#,SCN,TIME from v$restore_point order by
time;
NAME DATABASE_INCARNATION#
SCN TIME
-------------------- --------------------- ----------------------
----------------------------------------
PRE_DMLOAD_1 4
18116228292 30-JUN-12 12:24:20.000000000
select SEQUENCE#,FIRST_CHANGE#,FIRST_TIME,NEXT_CHANGE#,NEXT_TIME from
v$archived_log where SEQUENCE# between 2634 and 2638;
SEQUENCE# FIRST_CHANGE# FIRST_TIME NEXT_CHANGE#
NEXT_TIME
---------- ------------------- ------------------ -------------------
------------------
2634 18115806724 27-JUN-12 13:01:05 18116218687
30-JUN-12 12:22:25
2635 18116218687 30-JUN-12 12:22:25 18116228029
30-JUN-12 12:24:07
2636 18116228029 30-JUN-12 12:24:07 18116240885
30-JUN-12 12:40:48
2637 18116240885 30-JUN-12 12:40:48 18116288998
01-JUL-12 01:34:31
2638 18116288998 01-JUL-12 01:34:31 18116309343
01-JUL-12 01:35:15
shutdown immediate;
startup mount;
flashback database to restore point PRE_DMLOAD_1;
ERROR at line 1:
ORA-38754: FLASHBACK DATABASE not started; required redo log is not available
ORA-38761: redo log sequence 2634 in thread 1, incarnation 4 could not be
accessed
We create a restore point bfore running batch processing each night and
beforehand delete old archivelogs and restore points:
drop old restore points.
delete noprompt archivelog until time 'sysdate-0.5';
alter system switch logfile;
and then create the new restore point.
This has worked fine until now. In this case archivelog sequence 2634 spans
3 days and so was deleted with "delete noprompt archivelog until time
'sysdate-0.5'". Nonetheless I would have expected that we would be ok having
the archivelog that was current at the time the restore point was created and
the previous archivelog. But not on this occasion.
So my question is how can I determine if an archivelog will be needed for
flashing back to a restore point before I detete it?
Regards,
Fergal
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