Behaviour of v$standby_log; during real time apply...

hi,
i would like to understand the behaviour of this view, during REDO APPLY or real time apply using standby redo log configuration. as in my db, when there is a apply in progress i see the status column having value ACTIVE and DBID column has value of standby DBID where the apply is in progress and then status column goes to UNASSIGNED value and DBID column has no value inside it....i mean blank......why is this so? request you to please help me to understand this....following is the log
SQL> select * from v$standby_log;
GROUP# DBID THREAD# SEQUENCE# BYTES BLOCKSIZE USED ARC STATUS FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME LAST_CHANGE# LAST_TIME
7 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
8 3903727333 1 58534 104857600 512 338944 YES ACTIVE 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12
9 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
10 3903727333 2 38929 104857600 512 235008 YES ACTIVE 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12
11 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
12 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
6 rows selected.
SQL> /
GROUP# DBID THREAD# SEQUENCE# BYTES BLOCKSIZE USED ARC STATUS FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME LAST_CHANGE# LAST_TIME
7 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
8 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
9 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
10 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
11 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
12 3903727333 2 38931 104857600 512 5120 YES ACTIVE 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12

GROUP# DBID THREAD# SEQUENCE# BYTES BLOCKSIZE USED ARC STATUS FIRST_CHANGE# FIRST_TIM NEXT_CHANGE#
7 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
8 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
9 UNASSIGNED 1 0 104857600 512 0 NO UNASSIGNED
10 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
11 UNASSIGNED 2 0 104857600 512 0 NO UNASSIGNED
12 3903727333 2 38931 104857600 512 5120 YES ACTIVE 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12 2.3217E+10 05-JAN-12Here DBID would be same,
These standby redo log file groups can contain either of thread 1 or thread2, Multiple threads are used in RAC environment.
In general architecture, Once if any log switch (or) redo log is full then these will be dumped into archive log files, then it will assigned to new redo log files. Here in primary redo log file, you can see the status as Current, Active, Inactive so on.
During real time apply, whenever data written into primary redo log files, At the same time log writer will be active and that will be assigned to the one of the redo log file..not redo log file, you have to say standby redo log in standby database.
here unassigned means, this standby redo log file, can be used for next time, might earlier status as "active". Whenever standby redo log file is active then only DBID you can see.
If its in unassigned it will be idle, again if any new allocation then these will become active. its like chain/loop. It is very much normal behaviour.
UNASSIGNED - Online redo log has never been written to. This is the state of a redo log that was just added, or just after a RESETLOGS when it is not the current redo log.
ACTIVE - Log is active but is not the current log. It is needed for failure recovery. It may be in use for block recovery. It may or may not be archived.
HTH.

Similar Messages

Real-time apply cascaded logical standby database

Hi
I have a primary database orcl
Pysical standby database orcl_std
Cascaded logical standby database orcl_tri which receives archivelogs from orcl_std
Real time apply is enabled both in orcl_std (physical standby) and orcl_tri (logical standby)
When I create a table in primary orcl, I am unable to see it on orcl_tri (Although real time apply is enabled)
However, when I switch log in primary, I can see the new table on orcl_tri.
My question is, why realtime apply is not working in my scenerio ?
orcl_std : ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION USING CURRENT LOGFILE;
orcl_tri: ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;
Oracle 11.2.0.3.0

Hi mseberg,
Thanks for your reply.
There is no load or network issue as I`ve just created these databases for the experiement.
I have the same output from standby and primary databases.
SQL> select bytes/1024/1024 from v$standby_log;
BYTES/1024/1024
             10
             10
             10I can see below output in standby alertlog
Fri Nov 16 08:39:51 2012
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE
ALTER DATABASE START LOGICAL STANDBY APPLY (orcl)
with optional part
IMMEDIATE
Attempt to start background Logical Standby process
Fri Nov 16 08:39:51 2012
LSP0 started with pid=37, OS id=16141
Completed: ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE
LOGMINER: Parameters summary for session# = 1
LOGMINER: Number of processes = 3, Transaction Chunk Size = 201
LOGMINER: Memory Size = 30M, Checkpoint interval = 150M
LOGMINER: SpillScn 1953318, ResetLogScn 995548
LOGMINER: summary for session# = 1
LOGMINER: StartScn: 0 (0x0000.00000000)
LOGMINER: EndScn: 0 (0x0000.00000000)
LOGMINER: HighConsumedScn: 1955287 (0x0000.001dd5d7)
LOGMINER: session_flag: 0x1
LOGMINER: Read buffers: 16
Fri Nov 16 08:39:55 2012
LOGMINER: session#=1 (Logical_Standby$), reader MS00 pid=30 OS id=16145 sid=49 started
Fri Nov 16 08:39:55 2012
LOGMINER: session#=1 (Logical_Standby$), builder MS01 pid=39 OS id=16149 sid=44 started
Fri Nov 16 08:39:55 2012
LOGMINER: session#=1 (Logical_Standby$), preparer MS02 pid=40 OS id=16153 sid=50 started
LOGMINER: Turning ON Log Auto Delete
LOGMINER: Begin mining logfile during commit scan for session 1 thread 1 sequence 202, +DATA/orcl_std/archivelog/2012_11_15/thread_1_seq_202.349.799450179
LOGMINER: End mining logfiles during commit scan for session 1
LOGMINER: Turning ON Log Auto Delete
LOGMINER: Begin mining logfile for session 1 thread 1 sequence 202, +DATA/orcl_std/archivelog/2012_11_15/thread_1_seq_202.349.799450179
LOGMINER: End   mining logfile for session 1 thread 1 sequence 202, +DATA/orcl_std/archivelog/2012_11_15/thread_1_seq_202.349.799450179
Fri Nov 16 08:40:04 2012
LOGSTDBY Analyzer process AS00 started with server id=0 pid=41 OS id=16162
Fri Nov 16 08:40:05 2012
LOGSTDBY Apply process AS03 started with server id=3 pid=45 OS id=16175
Fri Nov 16 08:40:05 2012
LOGSTDBY Apply process AS04 started with server id=4 pid=46 OS id=16179
Fri Nov 16 08:40:05 2012
LOGSTDBY Apply process AS01 started with server id=1 pid=42 OS id=16167
Fri Nov 16 08:40:05 2012
LOGSTDBY Apply process AS05 started with server id=5 pid=47 OS id=16183
Fri Nov 16 08:40:05 2012
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Real-time apply in Maximum Performance Mode Not Working

We have configured physical standby database in maximum performance mode. It's working perfectly fine. Archive logs are being applied to the physical standby.
We can open the DB in read-only mode, but real-time apply is not working. Physical standby database is lagging behind the primary db by an archive log. As soon as primary database generates an archive log, it's transported over to the standby and applied immediately by the media recovery process. But real-time redo is not working. Standby redo logs have been configured.
On Physcial Standby:
SQL> alter database recover managed standby database using current logfile disconnect ;
Database Altered.
SQL> select group#, DBID, status,first_time, last_time from v$standby_log ;
GROUP# DBID STATUS FIRST_TIM LAST_TIME
4 UNASSIGNED UNASSIGNED
5 UNASSIGNED UNASSIGNED
6 UNASSIGNED UNASSIGNED
7 UNASSIGNED UNASSIGNED
SQL> select * from v$dataguard_stats ;
NAME
VALUE
UNIT TIME_COMPUTED
apply lag
+00 00:31:36
day(2) to second(0) interval 22-JUN-2010 08:42:06
transport lag
+00 00:31:34
day(2) to second(0) interval 22-JUN-2010 08:42:06
As you could see from the output above, value of transport and apply lag is equal to the elapsed time since last archive log switch.
********* Standby init.ora
db_name = CPRD
db_unique_name = CPRDS
instance_name = CPRD
service_names = hrDBSBY.WORLD
log_archive_format = CPRD%r%s.%t
log_archive_dest_1 = "location=f:\orarch\hresysprod"
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log_archive_config='dg_config=(cprd,cprds)'
fal_server=hresysprod
fal_client=hresysprods
standby_file_management=auto
log_archive_trace=1
log_file_name_convert = ('hresysprod','hresysprods')
db_file_name_convert = ('hresysprod','hresysprods')
remote_login_passwordfile = exclusive
******* Primary init.ora
log_archive_config='dg_config=(cprd,cprds)'
fal_server=hresysprods
fal_client=hresysprod
standby_file_management=auto
log_archive_format = CPRD%r%s.%t
log_archive_dest_1 = "location=f:\orarch\hrESYSPROD"
log_archive_dest_2='service=hresysprods async db_unique_name=cprds valid_for=(primary_role,online_logfile)'
log_archive_trace=1
remote_login_passwordfile = exclusive
Please advise.
Thanks,
jay

Hi,
In your case you are using ARC process for redo transfer as you have not specified any process in log_archive_dest_2 and default is arch.
I will suggest you to use LGWR to transfer the redo to standby and also check the size of standby redo logs on standby is same to the size of online redo logs on primary
Regards
Anudeep

11gR2 Real Time Apply / open read only

Hi,
I have a single instance primary database with a physical standby. The release is 11.2.0.1.0.
Max Availability mode
LGWR SYNC transport
Data Guard Broker configuration enabled
Both the primary and standby database are registered with the Grid Infrastructure (Standalone installation on each server, no cluster)
When I stop and start the standby database it seems to default to open read only using Managed Real Time Recovery.
SQL> SELECT DEST_ID, RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS
2> WHERE DEST_ID=2;
DEST_ID RECOVERY_MODE
2 MANAGED REAL TIME APPLY
I do not want to Active Data Guard on this particular database. So I removed and added the database again using srvctl this time supplying the -s mount flag. Now when I stop/start the standby it opens in mount mode and MANAGED recovery which is OK.
My question is why did the standby automatically get opened in read only. Is the a change in behaviour introduced along with Active Data Guard? Is the default behaviour for a database registered with Grid Infrastructure to simply start the database in open mode and becuase this is 11.2 standby this means open read only?
Thanks

Dear user234564,
This has been introduced in Oracle Database 11g Data Guard New Features and it is called the Active Data Guard. With the new release you can open the physical standby database in read only mode and the real time apply will continue as it is on the mount stage. This ability has not been granted on 10g. So i think it could be the normal behaviour.
11g physical standby database will be opened and the MRP process will still apply the archivelogs to the standby database. You can simply have it tested.
Please refer;
http://download.oracle.com/docs/cd/E11882_01/server.112/e10700/manage_ps.htm#CHDGJEFF
Let me give you a quick hint but it is off topic;
The number of standby databases that a primary database can support is increased from 9 to 30 in this release.
The capability to create 30 standby databases, combined with the functionality of the Oracle Active Data Guard option, allows the creation of reader farms that can be used to offload large scale read-only workloads from a production database.Hope That Helps.
Ogan

Real - Time Apply some times uses Archived log file

Hi All,
I have a doubt on real time apply in Oracle 10g 10.2.0.4 version where arch process has been configured on primary database and standby has been configured for maximum performance mode with real time apply.
But in standby alert log file i use to find below message rarely
Media Recovery Log /oraclearch/oraarch/ctdr/5548.dbf
Media Recovery Log /oraclearch/oraarch/ctdr/5549.dbfSo my doubt is why archived files are applied as standby has been configured for real time apply where it should apply only from standby online redo log files.
Also i dont find any information on standby database in the view v$standby_log that these standby online log files have been archived in archived column, so how to find how much of data has been written by rfs process on SRL's...
-Yasser

hi,
As the remote file server (RFS) process writes the redo data to standby redo log files on the standby database, log apply services can recover redo from standby redo log files as they are being filled.
please check http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/log_apply.htm
thanks,
baskar.l

Real time apply for logical standby

Hi
Oracle 11.2.0.3.0
I have a primary database orcl and logical standby database orcl_std.
Real time apply is enabled. I have standby redologs in both primary and standby sides and I`ve started recovery with below command:
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;
When I create a new table in primary database, I am unable to see it on standby database (Although real time apply is enabled)
However, when I switch log in primary, I can see the new table in standby database.
My question is, why realtime apply is not working in my scenerio ? I was expecting to see the new table immediately in standby database once it is created in primary database. Why am I supposed to wait for log switch in real time apply ?

Using Real-Time Apply to Apply Redo Data Immediately
http://docs.oracle.com/cd/E11882_01/server.112/e25608/log_apply.htm#i1022881
1.What is compatible parameter, it should be 11.1
2.Try to check parameters mentioned in below link:
http://easyoradba.com/2011/01/10/real-time-apply-in-oracle-data-guard-10g/
Regards
Girish Sharma
Edited by: Girish Sharma on Nov 15, 2012 12:37 PM

How Real Time Apply works while physical standby is open in Read Only mode

Hi,
With Active data guard option, we can open physical standby DB in read only mode, while redo log are being applied. (Real Time Query)
Standby Redo log (SRL) enables Real Time Apply (with "USING CURRENT LOGFILE" clause in recover database command on standby DB)
I am interested to know, how Real Time Query works ?
What is the mechanism with allows us to open physical standby DB in read only mode while redo logs are being applied continuously ?
Regards,
Sujit

Dear user7419391,
That is a new feature in Oracle Database 11g. MRP can use the real time apply in 10g but the concept here is different.
Taken from the following document;
http://www.ascent.co.za/documents/oracle/Oracle%20databse%2011g%20Active-Data-Guard%20datasheet.pdf
*Unique Advantages of Oracle Active Data Guard*
+Active Data Guard is an evolution of Data Guard technology, providing unique+
+performance advantages while leveraging all other enhancements included in Oracle+
+Data Guard 11g. For example, any Data Guard 11g physical standby database can+
+be easily converted to a Snapshot Standby. A Snapshot Standby is open read-write+
+and is ideally suited as a test system, able to process transactions independent of the+
+primary database. A Snapshot Standby maintains protection by continuing to receive+
+data from the production database, archiving it for later use. When tests are+
+complete, a single command discards changes made while open read-write and+
+quickly resynchronizes the standby database with the primary.+
The other link in the previous post is excellent and you really have to read it to understand the active data guard aspects.
Regards.
Ogan

When to use Real Time Apply for Logical standby..!!

Hello All,
I have been trying many ways to speed up the archival on primary and improve sql apply on logical standby, but still we are getting about 45-50 mins of delay between primary and logical standby.
We wanted to have our transactions applied on logical standby within couple minutes. Which i guess wont be possible in async mode.
That's why i am planning to implement Real Time apply between primary and logical standby.
Now since both our databases are too far away from each other (Primary is in US and logical is in India) would it be recommended to implement real time apply in such scenario? And if implemented would it affect Primary DB Performance?
Also if there might be some packet loss or network hitch would Primary will try again and keep logical DB in Sync with Primary?
Any help or suggestions would be great.
Thanks.

yes, real time apply is recommended in your scenario.
however due to the geographical distance between your primary and standby; I would suggest to keep your standby in current mode - max performance ; ASYNC- itself. It would not affect the performace of the primary.
As long as you set the FAL parameters and configure tnsnames properly and ensure proper deletion policy for archivelog cleanup in primary ( so that it's not deleted before shipping if need be), you shouldn't find any problem with primary & standby synching.
Good Luck.
Cheers.

Logical standby real time apply problem

Hi all,
The real time apply for logical standby on my Oracle 10.2 DB is not working
SELECT SEQUENCE#, FIRST_TIME, APPLIED
FROM DBA_LOGSTDBY_LOG
ORDER BY SEQUENCE#;
SEQUENCE# FIRST_TI APPLIED
2113 07/10/09 NO
2115 07/10/09 NO
2116 07/10/09 NO
There is no error inside alert log.
Any help
Thanks

Using Real-Time Apply to Apply Redo Data Immediately
http://docs.oracle.com/cd/E11882_01/server.112/e25608/log_apply.htm#i1022881
1.What is compatible parameter, it should be 11.1
2.Try to check parameters mentioned in below link:
http://easyoradba.com/2011/01/10/real-time-apply-in-oracle-data-guard-10g/
Regards
Girish Sharma
Edited by: Girish Sharma on Nov 15, 2012 12:37 PM

Gap resolution is not always happening with real time apply

Hi
I noticed a strange behavior in one of my 10.2.0.4 dataguards , and I am wondering if anyone else has encountered it :
When there is an archive gap that need to be resolved , the gap is NOT always being identified and acted upon , when the recovery is started as such :
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION.
its just sitting there doing nothing, and nothing is written to the alert log regarding the gap and nothing is being transferred from the primary as needed.
However, if I restart the apply , omitting the 'USING CURRENT LOGFILE' clause , the gap is identified and acted upon, as such :
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION.
At first I thought its merely due to me stopping and starting the apply process ( nothing like a "reboot" , right ? ) , but that is not the case.
if I restart , but still use the USING CURRENT LOGFILE clause , the gap is still not being identified .
Anyone had this issue ? any theories as to why that happens ?

Using Real-Time Apply to Apply Redo Data Immediately
http://docs.oracle.com/cd/E11882_01/server.112/e25608/log_apply.htm#i1022881
1.What is compatible parameter, it should be 11.1
2.Try to check parameters mentioned in below link:
http://easyoradba.com/2011/01/10/real-time-apply-in-oracle-data-guard-10g/
Regards
Girish Sharma
Edited by: Girish Sharma on Nov 15, 2012 12:37 PM

How can I make Recover_Mode Is Real Time Apply in Data Duard

Hi Experts
I have Primary and Standby Databases I need to know how can I change the recover mode to Real Time Apply?
I run the following queury in Primary Site:
SELECT RECOVERY_MODE FROM V$ARCHIVE_DEST_STATUS WHERE DEST_ID=2;
RECOVERY_MODE
MANAGED
I have oracle 11g R2 / Windows Server 2008 R2!
Logs generated and transfered successfully!

Hello;
Cancel recovery on the standby and then.
SQL
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
Note: You should have Standby redo at both the Primary and Standby sites.
Best Regards
mseberg

RMAN in active data guard with real time apply ON without a catalog DB

I would like to know whether I can take RMAN backups (both level 0 & incremental) in active data guard with real time apply ON without a catalog database. version is 11.2.0.3.2. Will it make difference in the control file of standby syncing with primary? Can I use these backups on primary to restore and recover the database(including control file backup)?

Thank you very much msberg. Could you please answer the below queries as well?
Should I cancel Real Time Apply before starting RMAN?
Will it make difference in the control file of standby syncing with primary? Is it possible to use these backups on primary to restore and recover the database(including control file backup)? If possible, how will I do that?

Enabling the Active Dataguard and Real Time Apply

11.2.0.2 on AIX
I gather that , to enable Active Dataguard, you need to execute
STARTUP ; ----not startup mount
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;The above commands will enable both Active Dataguard (Real Time QUERY) and Real Time Apply. Right?
To enable just 'Real Time Apply' , I need to
startup mount
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;Am I right ?
Question on 'WITH SESSION SHUTDOWN' clause
While googling I've come across the following variant with an additonal 'WITH SESSION SHUTDOWN' clause
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE WITH SESSION SHUTDOWN;What difference does this clause bring ?
Is this claused used to enable Active Dataguard feature or 'Real Time Apply' or both ?

I gather that , to enable Active Dataguard, you need to execute
STARTUP ; ----not startup mount
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;
The above commands will enable both Active Dataguard (Real Time QUERY) and Real Time Apply. Right? Yes, It will be in both recovery / realtime + Read only mode, Also you can use
To enable just 'Real Time Apply' , I need to
startup mount
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT;Am I right ?Yes. It will be in just recovery/real time mode.
Question on 'WITH SESSION SHUTDOWN' clause
While googling I've come across the following variant with an additonal 'WITH SESSION SHUTDOWN' clause
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE WITH SESSION SHUTDOWN;What difference does this clause bring ?
Is this claused used to enable Active Dataguard feature or 'Real Time Apply' or both ?It has multiple options based on startup type
For this example check link of Julian Dyke.
http://juliandyke.wordpress.com/2010/10/14/oracle-11gr2-active-data-guard/

Recovery_mode managed vs managed real time apply

Hello All,
I am using Oracle 11.2.0.3
My primary database is an Oracle RAC 2 nodes database with ASM and my standby database is a single instance physical standby database on file systems.
My protection mode is MAXIMUM PERFORMANCE
What is the difference I do :
alter database recover managed standby database using current logfile disconnect; (managed real time apply)
and
alter database recover managed standby database disconnect; (managed)
Does managed real time apply have any performance impact or disadvantage?
Regards,

Does managed real time apply have any performance impact or disadvantage?
Performance i don't think will not be..
For the rest of the queries you have to deside what is real use of it..? I will so you path of pros and cons of it
Difference between real time apply and active dataguard
What are the pros and cons using Active Data Guard vs Data Guard?
redo apply Vs real time apply

Redo apply Vs real time apply

Hi all ;
I have some confusion regarding redo apply Vs real time apply.
When applying redo data in standby site , how do we find whether it was done by redo apply or real time apply ?
Please discuss in detail. I need some clarification about this.
Thanks in advance ..

Hi baris ,
Thanks .. again little confusion. NO documents to find answer.
If a logical corruption occurs on your primary by a human mistake such as truncate table, wrong delete etc,
so a delayed standby is more appropriate. Furthermore you can configure flashback database feature
on your standby database when you use real time apply.
Is this possible ?
1) Do you mean flashback will be enabled only in standby database except primary database ?
What are the changes made in primary that only transfer to standby if so ,
2) How do we recover deleted objects in standby ?
FYI : I have a doubt with time delay option, we will discuss this things in new thread. please do NOT mind it.

Behaviour of v$standby_log; during real time apply...

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