RE: [Q] what differtent between logical standby database and physical standby DB?

From: Riyaj Shamsudeen <rshamsud_at_jcpenney.com>
Date: Thu, 08 Apr 2004 09:45:59 -0500
Message-id: <003f01c41d78$356a0c80$212f200a@rshamsudxp>

Guess, I should have been careful in my wording :-) Let me reword it and correct me If I still get this wrong..

Physical standby database applies the changes from the redo log file just like a recovery does. So, there may be internal operations such as extent control, segment header changes, index splits etc, which also would be applied. If there is any corruption in these change vectors that will be propagated too.

But in a logical standby only non-internal SQL is reconstructed and so, the possibility of propagating the corruption is far less than the physical standby. Also, the SQL reconstruction will detect most corruption possibilities, whereas the physical standby might not capture most of that.

Thanks
Riyaj "Re-yas" Shamsudeen
Certified Oracle DBA

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tanel Põder Sent: Thursday, April 08, 2004 8:46 AM
To: oracle-l_at_freelists.org
Subject: Re: [Q] what differtent between logical standby database and physical standby DB?

Original Message ----- From: "Riyaj Shamsudeen" <rshamsud_at_jcpenney.com>
> There are many pros and cons to both. Name a few: logical standby db
> will not propagate redo log corruption, db should be open for logical
> standby etc.

Actually logical standby can propagate redo log corruption, since the SQL statements applied to standby are constructed from redo, archive or standby logs using logminer...

Tanel.

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Received on Thu Apr 08 2004 - 09:51:18 CDT