Discoverer and Logical Standby

We don't wish to run Discoverer against our production database. To that end, we have set up a logical standby on another db server. We plan to allow our users to run their Discoverer reports using the data from the standby database.
Q: Does anyone have any 'lessons learned' or comments regarding this type of setup? Any 'gotchas'?
thanks, all.....

a physical standby is a byte-exact copy.
If you would overwrite all files of the primary by the corresponding standby files, Oracle won't notice. That said, the database isn't available for normal operations, you can not create any segments in it.
A logical standby database is a duplicate database in which all INSERT, UPDATE etc statements are re-executed.
There are limitations with respect to datatypes: not all datatypes are supported.
Tables with unsupported datatypes are automagically suppressed from the standby. The database is open and can be used.
However, as it is not a byte-exact copy, you can not use it for Disaster Recovery purposes.
Sybrand Bakker
Senior Oracle DBA

Similar Messages

What are advantage and disadvantage for Physical Standy and Logical Standby

HI,
What are advantage and disadvantage for Physical Standy and Logical Standby configuration?
Thanks
Ken

Logical standby database
The key advantage for logical standby databases is that they're opened read/write, even while they're in
applied mode. That is, they can be used to generate reports and the like. It is indeed a fully functional
database. Also, additional indexes, materialized views and so on can be created.
However (this being a disadvantage) not all datatypes are supported.
Oracle (or more exactly the log apply services) uses the primary database's redo log, transforms them into
SQL statements and replays them on the logical standby database.
Physical standby database
A physical standby database is a byte for byte exact copy of the primary database. This also means that
rowids stay the same in a physical standby database environment.
Oracle (or more exactly the log apply services) uses the primary database's redo log to recover the
physical database.
A physical standby database might be opened read only; however, the received logs are in this case not
applied. When the logs are applied, the database is not accessible (it is then in a managed recovery state).
Regards,

Difference between physical and logical standby database

What is the difference between physical and logical standby database?

Hi,
Physical Standy where its a read only DB.
Logs are applied.
Logical Standy where it can be Read / Write DB and the logs are applied in terms of SQL Statements.
Thanks & Regards,
Pavan Kumar N

Physical standby and logical standby

Hi,
Why we mention standby_archive_dest and log_archive_Dest in standby init.ora.
bcz there is no activity at physical standby.so why we set two parameters?
what is difference between physical stand by and logical standby?

Hi,
A logical standby database contains the same logical information as the production database, although the physical organization and structure of the data can be different. The SQL apply technology keeps the logical standby database synchronized with the primary database by transforming redo data received from the primary database into SQL statements and then executing the SQL statements on the standby database. This makes it possible for the logical standby database to be open read-write and accessed for queries and reporting purposes at the same time the SQL is being applied to it.
Logical vs Physical Standby database
http://www.orafaq.com/node/957
Regards,
Tom
Edited by: Soli on 19.8.2009 13:48

Best practice on using Flashback and Logical Standby

Hello,
I'm testing a fail-back scenario where I first need to activate a logical standby, then do some dummy transactions before I flashback this db and resme the redo apply. Here is what the steps look like:
1)     Ensure logical standby is in-sync with primary
2)     Enable flashback on standby
3)     Create a flashback guaranteed restore point
4)     Defer log shipping from primary
5)     Activate the logical standby so it’s fully open to read-write
6)     Dummy activities against the standby (which is now fully open)
7)     Flashback the database to the guaranteed checkpoint
8)     Resume log shipping on primary
9)     Resume redo apply on secondary
In the end, i can see the log shipping is happening but the logical standby does not apply any of these..and there is no error in the alert log on Standby side. But the following query could explains why the standby is idle:
SELECT TYPE, HIGH_SCN, STATUS FROM V$LOGSTDBY;
TYPE HIGH_SCN STATUS
COORDINATOR ORA-16240: Waiting for log file (thread# 2, sequence# 0)
ORA-16240: Waiting for log file (thread# string, sequence# string)
Cause: Process is idle waiting for additional log file to be available.
Action: No action necessary. This informational statement is provided to record the event for diagnostic purposes.
I dont understand why it's looking for sequence #0 after the flashback.
Thanks for the help.

Hello;
I hesitate to answer your question because you are not doing a good job of keeping the forum clean :
Total Questions: 13 (13 unresolved)
Please consider closing some of you old answered questions and rewarding those who helped you.
No action necessary.
Do you really have a thread 2? ( Redo thread number )
Quick check
select applied_scn,latest_scn from v$logstdby_progress;Use the DBA_LOGSTDBY_LOG View if you don't have a thread 2 then the sequence# is meaningless.
COLUMN DICT_BEGIN FORMAT A10;
SELECT FILE_NAME, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE#,
TIMESTAMP, DICT_BEGIN, DICT_END, THREAD# AS THR# FROM DBA_LOGSTDBY_LOG
ORDER BY SEQUENCE#;Logical Standby questions are difficult, not a lot of them out there I'm thinking.
Check
http://docs.oracle.com/cd/E14072_01/server.112/e10700/manage_ls.htm
"Waiting On Gap State" ( However I still believe you don't have a 2nd thread# )
OR
http://psilt.wordpress.com/2009/04/29/simple-logical-standby/
Best Regards
mseberg
Edited by: mseberg on Apr 26, 2012 5:13 PM

CPU patch procedure with physical and logical standby database in place

Hello All,
I've also placed this in the Upgrades forum, but perhaps this is the best place to have put it.
I'm trying to compile a decent set of steps for applying the CPUOCT2008 patch to our production RAC cluster which has both a logical and physical standby in place. I've read a tonne of documentation, including the CPU readme, DOCID 437276.1 and 278641.1. I''ve also read through the Upgrading Databases in a Data Guard Configuration chapter of Dataguard Concepts and Administration. The last doc mentioned is really for upgrading a full version of Oracle rather than applying a CPU (at least I think that's the case). DocID 437276.1 is rather sparse on details.
I guess what I'm trying to understand is the proper method for applying the patch with the logical standby in place. The physical standby looks pretty straightforward. After running opatch on it as well, it will basically have all of the changes applied to the primary shipped over and applied as per the normal primary/standby relationship. Will the same be true for the logical (having applied the patch, and then re-enabling SQL apply)? Should I aim to have it work that way? By that I mean start it up and re-enable sql apply and then upgrade the primary. Or, am I to apply the catcpu.sql script to it as well before re-enabling the sql apply? Am I wrong in regards to the physical standby as well i.e. should the catcpu also be applied directly to it?
Thanks very much in advance.
Cheers,
Chris
Edited by: chris.baron on Dec 12, 2008 11:38 AM

Given the fact that your system is far from main-stream I'd recommend opening an SR with Oracle Support Services (metalink) and asking them.
If you would like to publish a White Paper on your experience after you have successfully completed the project let me know off-line.

Refresh Schema in Primary (and Logical Standby)

Does anyone have a recommendation for the best way to refresh a 16Gb schema in a Primary Database that has a logical standby?
I attempted to refresh our main schema in our Primary by using IMPDP. I tried to follow the same steps as I would if I had to upgrade a Primary database with a Logical Standby in place. I defered the Log archive log dest state associated with the logical standby, stopped the SQL Apply on the standby and disabled Data Guard, then dropped the schema in the Standby, created and imported the schema. i then performed the drop, recreate and import in the Primary. After that I did a DBMS_LOGSTDBY.BUILD on the Primary. Finally I enabled DG, restarted the apply and enabled the log arch dest on the primary.
One issue I did have was that i did not defer the archivelogs until after the import had started so it did send some archives over - of course DG was disabled and the apply was off but now the status of DG is normal but i have a big gap in Last Received Log and Last Applied Log and of the missing archives, the oldest have 'Committed Transactions Applied', newer ones have 'Not Applied' and the newest have 'Not Received'.
I think I'm hosed but I am confused on the best approach. I did try just to perform the import on the Primary previously (last year) but I remember that the volume of data killed the replication.
This is 10.2.0.4 on Windows 2003 Server (64bit)
Thanks
Graeme

i suppossed that you did : alter database open resetlog; right?
In first place, try to see any error in redo transport:
alter system switch logfile;
select status, error from v$archive_dest where dest_id = 2;
any error?
for more information, please check:
http://www.idevelopment.info/data/Oracle/DBA_tips/Data_Guard/DG_45.shtml

Apply CPUOCT2008 with both a physical and logical standby in place

Hello All,
I'm trying to compile a decent set of steps for applying the CPUOCT2008 patch to our production RAC cluster which has both a logical and physical standby in place. I've read a tonne of documentation, including the CPU readme, DOCID 437276.1 and 278641.1. I''ve also read through the Upgrading Databases in a Data Guard Configuration chapter of Dataguard Concepts and Administration. The last doc mentioned is really for upgrading a full version of Oracle rather than applying a CPU (at least I think that's the case). DocID 437276.1 is rather sparse on details.
I guess what I'm trying to understand is the proper method for applying the patch with the logical standby in place. The physical standby looks pretty straightforward. After running opatch on it as well, it will basically have all of the changes applied to the primary shipped over and applied as per the normal primary/standby relationship. Will the same be true for the logical (having applied the patch, and then re-enabling SQL apply)? Should I aim to have it work that way? By that I mean start it up and re-enable sql apply and then upgrade the primary. Or, am I to apply the catcpu.sql script to it as well before re-enabling the sql apply? Am I wrong in regards to the physical standby as well i.e. should the catcpu also be applied directly to it?
Thanks very much in advance.
Cheers,
Chris

Given the fact that your system is far from main-stream I'd recommend opening an SR with Oracle Support Services (metalink) and asking them.
If you would like to publish a White Paper on your experience after you have successfully completed the project let me know off-line.

Time difference between physical and logical standby

Hi,
I have just been tasked on getting some info and setting up dataguard for some users for read-only/reporting purpose.
The 3 questions I am being asked are:
1. What is the time difference in applying changes from primary to physical standby compare to logical standby
2. What is the overhead maintenance of having a standby database?
3.What latency is involved?
I will be glad to have your input on this.
Thanks

Hi,
Physical Standy where its a read only DB.
Logs are applied.
Logical Standy where it can be Read / Write DB and the logs are applied in terms of SQL Statements.
Thanks & Regards,
Pavan Kumar N

What is the fundamental diff between physical standby and logical standby ?

What is the fundamental difference between logical standby and physical standby ?
What if I create a physical standby , now I would like to ask that is it possible to open it on read only mode ? If not , then why not ?
hare krishna
Alok

Nothing will explain you better Oracle than Oracle documentation :<br>
Standby Database Types<br>
<br>
Nicolas.

Resynchronization in primary and logical standby db

Hi,
I have implemented logical standby successfully first time.for testing i had shutdown logical standby server for last 60 hours.
when i start standby db and execute command
"ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE;"
but it is not synchronized data for last 3 days
Please help me
Vaibhav Dixit

i suppossed that you did : alter database open resetlog; right?
In first place, try to see any error in redo transport:
alter system switch logfile;
select status, error from v$archive_dest where dest_id = 2;
any error?
for more information, please check:
http://www.idevelopment.info/data/Oracle/DBA_tips/Data_Guard/DG_45.shtml

Crystal Reports and Logical Standby

Hello,
We built a logical standby (v 10.2.0.3). Users are trying to run Crystal Reports but are getting 'table not found' in the schema browser. It works fine on the Primary. Priv's for the user are the same on both Primary and Standby.
Has anyone had this issue and resolved it?
Thanks in advance.
Gina

Gina,
Refer to this oracle documenation for more information, what type of statement are supported and not supported.
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/data_support.htm#SBYDB00305
Regards

Physical and Logical Standby

Hi
I just wanted to know can i have one Physical and One Logical Standby for a Single Primary Database. Is there any precautions and steps to be followed .
Thanks

user9366471 wrote:
Hi
I just wanted to know can i have one Physical and One Logical Standby for a Single Primary DatabaseYes this is possible.
See following Oracle 10.2 example which talks also about cascaded standbys:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/cascade_appx.htm#i637055

Logica and Physical standby to the same Primary?

Hi,
I have a primary - standby setup operating in the production. i now have a requirement to configure a Logical standby to the primary server. Can I do that leaving the already existing physical standby intact?
Thanks,
Aswin.

Yes you can have both physical and logical standby from one primary. The logical standby will need to start as a second physical standby.

How to Create Primary DB and Physical/Logical Standby DB on the same host?

Now I encounter a issue. I want to create one Primary DB and one Physical standby DB and one Logical standby DB on the same host.
Create this env on the same host aims to test whether we can using EM Patching DP to apply patches on Primary/Physical/Logical DB successfully.
I try to setup this env but fails. I want to know more related issues about create Primary DB /Physical DB/Logical DB on the same host and how to configure between them.
Below steps is my try:
1. Create Primary DB on the /scratch/primary_db
2. Create Physical Db software only on the /scratch/physical_db
3. Create Logical Db software only on the /scratch/logical_db
4. Using EM Wizard to create physical standby database and logical standby database, and these two targets can show up on the "All Targets" Page.
5. But when using EM Patching DP, it fails and the reason is the listener of physical and logical db cannot configured well.
Issues:
So I want to know about how to configure physical db and logical db's listener using EM or manually?
If the listener name of Primary Db is LISTENER and the port is 1521,and the listener.ora is under the /scratch/primary_db/network/admin directory, then how to config physical db and logical db's listener's name and port?

Hi,
As this a test case then you need to create two more listener for each Oracle Home (/scratch/physical_db & /scratch/logical_db) make sure that they have different names and ports.
Then add the new listeners manually using GC?
Try it and let me know
Regards
Amin

Discoverer and Logical Standby

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