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Shutting down destination server in stream replication [message #357979] Fri, 07 November 2008 08:13 Go to next message
MIFI
Messages: 256
Registered: February 2008
Location: U.K.
Senior Member
Hi,
We have one way stream replication set up data is captured in production server and sent to destination server.
Now to apply OS patch,we need to restart the destincation server, can we do ity by just stopping apply process in destination server or we need to stop capture process.

If we do not need to stop capture process on production then is there any performance degradation on production server due to increase in queue data because apply will not be there

If we stop capture process,how do we capture and apply the changes after restarting the destination server so that both database are sync.

[Updated on: Fri, 07 November 2008 08:36]

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Re: Shutting down destination server in stream replication [message #357992 is a reply to message #357979] Fri, 07 November 2008 10:31 Go to previous messageGo to next message
varunvir
Messages: 325
Registered: November 2007
Senior Member
If you stop capture and apply process before shutdown the server,then after you startup 
the server you need to restart capture and apply manually.You dont need to stop these processes manually bacause when
you shutdown the server these processes will be stopped 
and after you restart the server these will be restarted automatically,
Moreover,If you stop the capture process and restart it,It
will always start capturing the changes from required checkpoint
scn or the point from where it stopped capturing.
The only thing you always take care of is archivelogs,Archivelogs containing required_checkpoint_scn should
be always present on the disk to make the capture process
work again.
Regards,
Varun Punj,
Re: Shutting down destination server in stream replication [message #357995 is a reply to message #357979] Fri, 07 November 2008 10:57 Go to previous messageGo to next message
MIFI
Messages: 256
Registered: February 2008
Location: U.K.
Senior Member
Thank you for you nice reply, what i am really confused about is if on monday apply status is aborted and it is aborted since friday d CaPTURE Process status is ENABLED and there is an error in dba_apply_error view, how do i apply changes that were done in production after error, so that nothing left before and after error.Only error is left.
I could not understand that how do i get the scn, which have been captured and queued in production and not applied in destination server and where do i define that apply start from which scn.

In Document, it is quite difficult to understand.

Could you please help me


Re: Shutting down destination server in stream replication [message #358003 is a reply to message #357995] Fri, 07 November 2008 12:32 Go to previous messageGo to next message
varunvir
Messages: 325
Registered: November 2007
Senior Member
If Apply status is aborted then your capture will pause for flow control....you can check in v$streams_capture for the state of capture process.
Capture process wont start capturing until you resolve the
issue with apply process and enable it again.
You can get the information about scn's in dba_capture view.
Regarding dba_apply_error:-
It show the errors which when apply process could not apply changes at the destination.The main reason for errors in
dba_apply_Error are conflicts.
You can wrinte conflict handler to resolve these errors or
You can resolve the errors manually and then delete the errors.
Regards,
Varun Punj,
Re: Shutting down destination server in stream replication [message #358225 is a reply to message #357995] Mon, 10 November 2008 03:29 Go to previous messageGo to next message
MIFI
Messages: 256
Registered: February 2008
Location: U.K.
Senior Member
Thank you for your help, two more question

Question 1
When in v$Stream_Capture state is Pause, it means it stops capturing, it means destination database is unsync with Production database because Production database is bening used 24x7,
when i eradicate the error, if Capture process will start capturing from current changes (after capture state changed to 'Capturing changes' from pause)or it will also include previous changes (Changes done after error occured and before capture state changed to 'Capturing changes' from pause)?


Question 2
What if i use following

declare iscn number;
begin
iscn:=dbms_flashback.get_system_change_number();
dbms_output.put_line('instantiation SC : '||iscn);
dbms_apply_adm.set_schema_instantiation_scn@destination_server(source_schema_name=>'PROD_S',source_database_name=>'PROD',instantiation_scn=>iscn,recursive=>true);
end;

exec dbms_apply_adm.start_apply(apply_name => 'DESTINATION_APPLY');
EXEC DBMS_CAPTURE_ADM.start_capture(capture_name => 'PROD_CAPTURE');

What will be the affect of above? because previously i used the above and Apply process status changed to ENABLED from Abort, but it was when production database was not being fully used.

[Updated on: Mon, 10 November 2008 03:38]

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Re: Shutting down destination server in stream replication [message #358297 is a reply to message #358225] Mon, 10 November 2008 10:59 Go to previous messageGo to next message
varunvir
Messages: 325
Registered: November 2007
Senior Member
Once cpture process change its state from paused to cpaturing
changes it will always start capturing changes from where it was
paused.As I said earlier,You should always have archivelogs
reuired for capturing changes from that point on the disk.
Regarding your second point,the procedure you shown me is used
for Instantiation.This is only reuired at the time of stream
set up.Basically,when you run that procedure,streams start
storing the redo information in a particular format in the stream
data dictionay that is different from oracle default data
dictionary.You dont need to run that procedure again and again.
Regards,
Varun Punj
Re: Shutting down destination server in stream replication [message #358301 is a reply to message #358225] Mon, 10 November 2008 11:12 Go to previous messageGo to next message
MIFI
Messages: 256
Registered: February 2008
Location: U.K.
Senior Member
Thank you sir, but how the Apply status changed from ABORT to ENABLED after running instantiation function and starting apply and capture process again.

Scondly could you please answer my following question, which is still unanswered

Using Oracle 10.2.0.3.0 on linux 64 bit
I have setup one way Stream replication(SCHEMA REPLICATION) from production to destination server, when i am executing the query DBA_CAPTURE_PREPARED_TABLES view, it is not showing two or three tables, one of the table have same number of records as production have. Do i need to do any thing, because replication is running fine.

Do i need not to worry because i am doing schema level replication and following view is showing the name of schema

SELECT * FROM DBA_CAPTURE_PREPARED_schemas;

Regards,
Re: Shutting down destination server in stream replication [message #358329 is a reply to message #358301] Mon, 10 November 2008 14:08 Go to previous message
varunvir
Messages: 325
Registered: November 2007
Senior Member
Upto my knowledge,If streaming was working before and the it
was aborted and then it was enabled after you run instantiation and restarted apply
and capture,it has nothing to do with instantiation in this case.Many times stream issue get resolved by restarting the
processes If it does not show any errors.
Regarding your second question please look in oracle
documentation.I really dont have much idea about that package.
Regards,
Varun Punj


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