Re: data guard real time apply question

From: Michael Dinh <mdinh235_at_gmail.com>
Date: Sat, 22 Sep 2012 07:46:58 -0700
Message-ID: <CAENwkM4k9Z_FQYx-LwPr_kVPmnk1yv4ftKaQUQA2ezx95EmFoA_at_mail.gmail.com>

Hello Joe,
Your alert log does not have: Recovery of Online Redo Log and I cannot tell if you are configured with Real time apply. Also, I would speculate that the number os SRL used at any given time depends on how active the database is.

Here are examples from my system: Note that group# 11 is the active one and is reflected in the LAST_TIME column.
SQL:PHYSICAL STANDBY> select GROUP#,SEQUENCE#,STATUS,LAST_CHANGE#,LAST_TIME from v$standby_log;

    GROUP# SEQUENCE# STATUS LAST_CHANGE# LAST_TIME ---------- ---------- ---------- ------------ ---------

        11      99245 ACTIVE       1.0547E+13 22-SEP-12
        12          0 UNASSIGNED
        13          0 UNASSIGNED
        14          0 UNASSIGNED
        15          0 UNASSIGNED
        16          0 UNASSIGNED
        17          0 UNASSIGNED
        18          0 UNASSIGNED

8 rows selected.

> tail -5 alert_<sid>.log

Media Recovery Waiting for thread 1 sequence 99245 (in transit) Recovery of Online Redo Log: Thread 1 Group 11 Seq 99245 Reading mem 0   Mem# 0: /oracle/oradata/<sid>/srl1.f
Sat Sep 22 06:27:16 2012
Archived Log entry 28122 added for thread 1 sequence 99244 ID 0x49541788 dest 1:

Dec 14  2010 /oracle/oradata/<sid>/srl8.f
May 31 19:39 /oracle/oradata/<sid>/srl7.f
Jun 30 18:06 /oracle/oradata/<sid>/srl6.f
Jun 30 18:08 /oracle/oradata/<sid>/srl5.f
Sep  6 00:07 /oracle/oradata/<sid>/srl4.f
Sep 20 10:51 /oracle/oradata/<sid>/srl3.f
Sep 22 06:27 /oracle/oradata/<sid>/srl2.f
Sep 22 07:37 /oracle/oradata/<sid>/srl1.f

HTH
-Michael.

On Fri, Sep 21, 2012 at 9:22 AM, Sweetser, Joe <JSweetser_at_icat.com> wrote:

> 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 Sat Sep 22 2012 - 09:46:58 CDT