Real Time Aooly and SCN'S

From: Ian MacGregor <>
Date: Fri, 11 Apr 2008 10:41:22 -0700
Message-ID: <>

Database A is primary Database B is a physical standby. The redo transport parameters include synch and affirm. Real time apply is not on.

If I query v$log on the primary and v$standby_log on the secondary I can that the lgs are in synch. If I look at the SCN on the primary it is ever increasing. The SCN on the secondary is static at one less than the first change# in the standby redo log. When that log switches the SCN becomes one less than the first change SCN, I the now current standby redo log.

This makes perfect sense as when real time apply is not on the changes are applied when upon log file switch.

If I go to real time apply, I thought the SCN would be changing every time I queried it. Instead it gets further behind. All the other factors, point to successful real time apply, but I don't understand what's happening with the SCN's

Ian MacGregor
Stanford Linear Accelerator Center

Received on Fri Apr 11 2008 - 12:41:22 CDT

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