RE: no archivelog incomplete recovery?

This isn't entirely true.  If you are lucky, and the online redo logs were 
never overwritten since the last cold backup, then you could apply the inactive 
archive logs up to just before the lost active one.  During the recovery you 
would specify the full path to the online redologs that need to be applied.  
This will work in either archivelog or noarchivelog mode.  In the case where 
your backup includes the online archive logs, it might be a good idea to save 
the unbroken online redologs just in case they can be used.  You might get 
lucky again and the online logs may have only been overwritten once.
Of course the above scenario will only work with a very quiet database.  99.99% 
of the databases would not be able to use this.


Pat



________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of John Smith
Sent: Monday, July 07, 2008 11:50 AM
To: Hemant K Chitale
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: no archivelog incomplete recovery?

So in effect, it is a trick question because the recovery will only be to the 
state at the last full backup, even if they do call it 'recovery'?  Since no 
archived logs will be available?

On Mon, Jul 7, 2008 at 10:01 AM, Hemant K Chitale 
<hkchital@xxxxxxxxxxxxxx<mailto:hkchital@xxxxxxxxxxxxxx>> wrote:

The keywords

"how to recover from a lost active online redo log in noarchivelog mode."

is ACTIVE !

As the database is in NOARCHIVELOG,  the only way a redo log could be ACTIVE 
would be if a Checkpoint hasn't been completed.
[had the lost online redo log been an Inactive one, you wouldn't have needed to 
do a Restore AT ALL, provided that you knew what to do !].

The only option is to Restore the last Consistent Backup.  IF the Consistent 
Backup included the Online Redo Logs, then you do not need to RESETLOGS.  If , 
however, the DBA had followed the advice of most "experts" and the 
documentation and did not backup his Online Redo Logs  [in his Consistent Cold 
Backup of a NoArchiveLog database] you would HAVE to do a RESETLOGS.

(having said that, I guess it should be obvious that I don't agree with most 
"experts" and the documentation that you should NEVER backup the Online Redo 
Logs.  This is one of the scenarios where a backup of the Online Redo Logs [in 
a Consistent Cold Backup] would make an OPEN less "uncomfortable" !

But coming back to the scenario provided in your test :  Although a RESETLOGS 
would be adviced, a RECOVER DATABASE wouldn't be needed at all.
  The sequence would be :
 a.  Restore Consistent Backup.
 b.  Verify if it included Online Redo Logs.  If if did not include the Online 
Redo Logs, go to step e.
 c.  STARTUP    {ie, the same as STARTUP MOUNT; ALTER DATABASE OPEN  (normal)}  
in sqlplus / as sysdba
 d.  exit from sqlplus prompt and get a pay raise
 e.  STARTUP MOUNT ; ALTER DATABASE OPEN RESETLOGS  in sqlplus / as sysdba

Hemant K Chitale



At 07:57 AM Monday, John Smith wrote:
I am studying for the OCP, and one of the practice test questions is how to 
recover from a lost active online redo log in noarchivelog mode.  the answer 
they give is to restore a consistent backup, startup in mount mode, perform a 
cancel based recovery, and open with resetlogs.

Is that answer correct?  I didnt think you could do a recovery if you arent in 
archivelog mode.


Hemant K Chitale
http://hemantoracledba.blogspot.com

"A 'No' uttered from the deepest conviction is better than a 'Yes' merely 
uttered to please, or worse, to avoid trouble."
Mohandas Gandhi Quotes :  
http://www.brainyquote.com/quotes/authors/m/mohandas_gandhi.html



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