Comments on: What is the difference between a logical and physical standby database? http://oraqa.com/2006/01/25/what-is-the-difference-between-a-logical-and-physical-standby-database/ Oracle Question and Answer Tue, 06 Jan 2009 09:48:10 +0000 http://wordpress.org/?v=2.7 hourly 1 By: Fahd Mirza http://oraqa.com/2006/01/25/what-is-the-difference-between-a-logical-and-physical-standby-database/comment-page-1/#comment-92 Fahd Mirza Mon, 30 Jan 2006 07:00:06 +0000 http://oraqa.com/2006/01/25/what-is-the-difference-between-a-logical-and-physical-standby-database/#comment-92 Got it, thanks a lot. Got it, thanks a lot.

]]> By: bob http://oraqa.com/2006/01/25/what-is-the-difference-between-a-logical-and-physical-standby-database/comment-page-1/#comment-91 bob Sat, 28 Jan 2006 21:08:30 +0000 http://oraqa.com/2006/01/25/what-is-the-difference-between-a-logical-and-physical-standby-database/#comment-91 The difference between physical and logical standby is in the way the changes from the primary are applied. Both created as an exact image of the primary database. Both receive redo logs from the primary database. The difference is that a physical standby is mounted (but not open) and applies the received redo logs just as in the case of media failure recovery. A logical standby reconstructs SQL statements from the received redo logs and executes them. A logical standby is (must be) opened and can with some limitations be used for reporting or other purposes. A physical standby is mounted and generally cannot be used for any other purposes. You can however switch temporarily to read-only mode and query it but synchronization with the primary will be paused until you return to the recovery mode. In 10g Rel. 2 you can also open it read-write and then flashback to its original state Vadim Bobrov Oracle Performance Tools http://www.fourthelephant.com The difference between physical and logical standby is in the way the changes from the primary are applied. Both created as an exact image of the primary database. Both receive redo logs from the primary database. The difference is that a physical standby is mounted (but not open) and applies the received redo logs just as in the case of media failure recovery. A logical standby reconstructs SQL statements from the received redo logs and executes them. A logical standby is (must be) opened and can with some limitations be used for reporting or other purposes. A physical standby is mounted and generally cannot be used for any other purposes. You can however switch temporarily to read-only mode and query it but synchronization with the primary will be paused until you return to the recovery mode. In 10g Rel. 2 you can also open it read-write and then flashback to its original state

Vadim Bobrov
Oracle Performance Tools
http://www.fourthelephant.com

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