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RE: About standby redo logs

From: Yerong He <>
Date: Fri, 7 Jan 2005 11:46:07 +1100
Message-ID: <>

Metalink note 219344.1 mentions there is a bug 2722195 "JUST TWO OF AVAILABLE STANDBY REDO LOGS ARE EVER USED IN A DATAGUARD ENVIRONMENT"
It has the status "Closed, Not a Bug" . :-)

-----Original Message-----
From: Carel-Jan Engel [] Sent: 6 January 2005 3:55
Subject: Re: About standby redo logs

Oracle documents that one needs at least the # of redo log groups on the primary + 1 on the standby, when standby redologs are used. I never saw a logswitch happen to another standby redologfile than the one previously used, so your observation is quite normal, though somewhat unexpected regarding the documented requirements. DG always seems to reuse the same logfile. I guess it has to do with the speed of the ARCH on the standby. I need to investigate this further if I get a chance on a testsystem, before I can get more conclusive on this.

Because normally DG-configurations have real HA requirements (if not, why was DG implemented), I tend to stay on the safe side and follow the Oracle docs. It's a little bit CYA, I admit, so be it.

Best regards,

Carel-Jan Engel

If you think education is expensive, try ignorance. (Derek Bok) ===

Upcoming appearances:

On Wed, 2005-01-05 at 15:33, Kamus wrote:

> I create 4 standby redo log groups, and use LGWR in primary site to
> transfer redo data, all are good. But when I query the V$STANDBY_LOG
> view, I found that only the status column of GROUP# 4(the first group
> of my standby redo logs) value is "ACTIVE" while all the others(5-7)
> also, only GROUP# 4's sequence# is a value greate than 0
> and THREAD# is 1, all others are 0 and 0.
> Any explains.



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Received on Thu Jan 06 2005 - 18:41:53 CST

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