RE: Manual Standby as alternative to dataguard

From: Ric Van Dyke <ric.van.dyke_at_hotsos.com>
Date: Tue, 16 Jun 2009 13:59:49 -0500
Message-ID: <C970F08BBE1E164AA8063E01502A71CF0147DFA0_at_WIN02.hotsos.com>

Yeap. If forced logging is not turned on then anything done with the nologging option will not be in the redo stream. This makes no difference if you're using a standby database or not. Since it's not in the redo stream it will not be applied to the standby database and it will not be there if you do any sort of recovery on the primary database as well. NOLOGGING means certain actions are not written to the redo log buffer; hence they don't get into the online redo log files so that means they are not in the archive log files.  

Why is it that the biz folks are so apposed to turning on forced logging? I presume they think there will be a performance hit, of course it all depends on what you are doing, but there is a good chance no one will notice.  

Also force logging is a database level setting, not the individual objects. It's one parameter that over rides the setting on an object, unlike most other settings. Just reading your text it sounds like you want to do this at the object level, you don't have to. Even if an object is set to NOLOGGING, if you set forced logging on then everything gets logged even for the objects with NOLOGGING.    

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Ric Van Dyke

Hotsos Enterprises

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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of sanjeev m Sent: Tuesday, June 16, 2009 2:42 PM
To: oracle-l_at_freelists.org
Subject: Manual Standby as alternative to dataguard  

Hi,  

At our site we are having difficulty getting approval from business to enable force logging on database objects.  

We plan to implement DR using manual method ie (shipping archive logs to DR site through cronjob, performing manual recovery on mounted standby controlfile)  

I understand without forcelogging all nologging transactions wont be recoverable. Is this true during recovery or after activating the standby?  

Is forcelogging a mandatory pre-requisite for implementing Dataguard? Has any of you have experience implementing Dataguard without force logging enabled.  

Will there be any issues during managed recovery if it encounters a nologging change? Wont we be hitting same issue if we are doing the recovery manually as opposed to MRP process?  

Regards,

Sanjeev.

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Received on Tue Jun 16 2009 - 13:59:49 CDT