data guard real time apply question

From: Sweetser, Joe <JSweetser_at_icat.com>
Date: Fri, 21 Sep 2012 16:22:06 +0000
Message-ID: <D18D6513433DF04394041EA42B53E91C9CD543FD_at_ICATMAIL1.ICAT.com>

I am a little confused.
11.2.0.2
Red Hat Linux 5.6
Physical standby database
Real time apply
Archive_dest_state_2 = SERVICE=<sid>_stby NOAFFIRM ASYNC VALID_FOR=(ALL_LOGFILES, PRIMARY_ROLE) DB_UNIQUE_NAME=<sid>_stby

Basic question is where does Oracle actually write the redo data on the standby side of the configuration? I would expect the timestamps on the standby redo logs to be current and/or match what I am seeing in the alert log but that is not the case.

If I understand the theory here (greatly simplified):

1. primary LGWR uses Oracle Net to talk to standby RFS (remote file server)
2. standby RFS writes redo data to standby online redo logs
3. standby online redo logs are applied to standby database using MRP (media/managed recovery process?)

Everything appears to be working correctly and I can see transactions applied to the standby as they occur on the primary by tailing the standby alert log as shown here:

Fri Sep 21 09:32:16 2012
Archived Log entry 3263 added for thread 1 sequence 82669 rlc 765739491 ID 0xb1c714a3 dest 2: RFS[15]: No standby redo logfiles created for thread 1 RFS[15]: Opened log for thread 1 sequence 82670 dbid -<whatever> branch 765739491 Fri Sep 21 09:32:17 2012
Media Recovery Log <full_path_to_archive_log_file>_1_82669_765739491.arc Media Recovery Waiting for thread 1 sequence 82670 (in transit) Archived Log entry 3264 added for thread 1 sequence 82670 rlc 765739491 ID 0xb1c714a3 dest 2: RFS[15]: No standby redo logfiles created for thread 1 RFS[15]: Opened log for thread 1 sequence 82671 dbid -<whatever> branch 765739491 Media Recovery Log <full_path_to_archive_log_file>_1_82670_765739491.arc Media Recovery Waiting for thread 1 sequence 82671 (in transit) Fri Sep 21 09:50:05 2012
Archived Log entry 3265 added for thread 1 sequence 82671 rlc 765739491 ID 0xb1c714a3 dest 2: RFS[15]: No standby redo logfiles created for thread 1 RFS[15]: Opened log for thread 1 sequence 82672 dbid -<whatever> branch 765739491 Fri Sep 21 09:50:05 2012
Media Recovery Log <full_path_to_archive_log_file>_1_82671_765739491.arc Media Recovery Waiting for thread 1 sequence 82672 (in transit)

Long listing of the standby redo logs:

ls -lart /u0*/oradata/<sid>/*rdo
<snip> 52429312 Sep 5 12:59 <full_path_to>/online_redo01.rdo
<snip> 52429312 Sep 5 12:59 <full_path_to>/online_redo02.rdo
<snip> 52429312 Sep 5 12:59 <full_path_to>/online_redo03.rdo

Sep 5 12:59 is when the standby database was last started.

Is there a reason why the modification times of the standby redo log files are not updated? Is Oracle actually writing to those files?

Thanks for any/all insight,
-joe

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Received on Fri Sep 21 2012 - 11:22:06 CDT