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

From: Riyaj Shamsudeen <rshamsud_at_jcpenney.com>
Date: Thu, 08 Apr 2004 08:02:39 -0500
Message-id: <002201c41d69$c5a17180$212f200a@rshamsudxp>

Redo logs supports physio-logical logging. Every bit change at the block level will generate a change vector which is bundled together in a redo record. In a physical standby database the changes are replayed using these redo records, very similar to the database recovery. The structure should not be altered in a way that can affect the log application, in this mode.
In a logical standby, the SQL statements are stripped off and reexecuted in the standby DB. Quest replication product is using this method for a long time now.

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.

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 dba1 mcc Sent: Thursday, April 08, 2004 7:32 AM
To: oracledba_at_lazydba.com; oracle-l_at_freelists.org Subject: [Q] what differtent between logical standby database and physical standby DB?

I read document it mention logical standby DB use "sql statements apply" and physical standby use "redo log apply". I got confuse. "redo log aplly" should same like "sql statements apply", due to "redo log" includes hundreds SQL statements.

Can anyone give me a hint?

Thanks.

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Received on Thu Apr 08 2004 - 08:06:57 CDT