RE: Data Guard and E-Business Suite

  • From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxx>
  • To: "martin.a.berger@xxxxxxxxx" <martin.a.berger@xxxxxxxxx>, "ric.van.dyke@xxxxxxxxxx" <ric.van.dyke@xxxxxxxxxx>
  • Date: Thu, 13 May 2010 15:00:56 -0400

Hi Martin,

Not exactly.  If you're not running DataGuard, the situation is slightly 
different.  If you've got nologging activity on your database, you need to 
ensure you've taken a backup *after* the latest bit of nologging activity, to 
ensure you have a clear path to recoverability.

If you are restoring/recovering a database from a backup taken prior to 
nologging activity, then any segments affected by the nologging activity will 
be logically corrupt.

This is different than the DataGuard case, where any nologging activity will 
immediately corrupt the standby database.  To avoid that immediate corruption 
of the standby, you must run with force logging set.

Hope that's clear,


From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Martin Berger
Sent: Thursday, May 13, 2010 2:49 PM
To: ric.van.dyke@xxxxxxxxxx
Cc: Richard.Goulet@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: Data Guard and E-Business Suite

Even without DataGuard, what's about a simple (rman) restore?
If you want to restore the EBS DB, you have to set FORCE LOGGING first?

really strange ... or funny - depends how you see it.


Am 13.05.2010 um 20:26 schrieb Ric Van Dyke:

This has been around "forever".  EBS has lots of stuff with NOLOGGIN and really 
was one of the reasons that the FORCE LOGGING option was developed.

Yea we can banter all day about the good the bad and the ugly of this, but the 
reality is that it's there.

I've been on EBS sites that have used a standby with forced logging.  I don't 
know if I've ever had a very comprehensive view of the impact of it (I would 
only be there for a few days/weeks in a consulting role).   I did some 
investigation into it at one site in particular and honestly I couldn't tell 
the difference. But it was not an exhaustive test of the entire suite.

The bottom line is YOU MUST USE FORCE LOGGING if you are serious about DR. If 
you just want to pretend like you have a DR site then sure don't use FORCE 
LOGGING.  Of course if you ever have to really use it, I hope your resume is up 
to date to the point just before the failure happens...

Ric Van Dyke
Hotsos Enterprises

From: oracle-l-bounce@xxxxxxxxxxxxx<mailto:oracle-l-bounce@xxxxxxxxxxxxx> 
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Goulet, Richard
Sent: Thursday, May 13, 2010 1:54 PM
To: oracle-l@xxxxxxxxxxxxx<mailto:oracle-l@xxxxxxxxxxxxx>
Subject: Data Guard and E-Business Suite

Have a question from one of the other folks here who is dealing solely with 
EBS.  They recently created a data guard standby database (play type) and went 
to try a failover to see how the app server would behave.  Again this is a play 
environment so errors are expected.  What she did not expect is that when 
failing over the database the system complained about block corruption.  We 
consequently figured out the it was due to the master db not having forced 
logging enabled so we know the master cause.  But we did check around the db 
and found a very large number of application tables that had nologging set.  
This e think is rather odd and is either a foul-up on the development side at 
Oracle or something they did deliberately for one reason or the other.  We're 
now wondering if setting forded logging on at the database level is going to 
cause us performance or other problems.  So, is anyone out there running EBS 
with a DG standby and forced logging on the master???  What effects are you 

Dick Goulet
Senior Oracle DBA/NA Team Lead
PAREXEL International

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