Re: Switchover of Logical Standby database

Thanks Mathias. I had just stumbled upon this myself and it is the way 
to go.

I have never found TAF very well documented and remember having to 
discover for myself the use of startup triggers in a physical standby 
configuration.

Thanks again

Gerry


Mathias Zarick wrote:
> Hi Gerry,
>
> try this in your after role change trigger:
> DBMS_SERVICE.STOP_SERVICE('YOUR_SERVICE');
> DBMS_SERVICE.DISCONNECT_SESSION('YOUR_SERVICE',DBMS_SERVICE.IMMEDIATE);
>
> HTH Mathias
>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
> Behalf Of Gerry Miller
> Sent: Saturday, December 17, 2011 12:08 AM
> To: CRISLER, JON A
> Cc: oracle-l@xxxxxxxxxxxxx
> Subject: Re: Switchover of Logical Standby database
>
>  Hi Jon
> Thanks for your response.
>
> The clients connect via tnsnames, which is set up for CTF and TAF.  I 
> originally created a physical configuration, which I tested for TAF and when 
> a switchover was performed it worked as I expected: a session that was 
> running a query on the original primary ran to completion on the new primary. 
>  I then converted the physical standby to a logical standby, dropping and 
> recreating the data guard broker configuration accordingly and switchover and 
> failover worked.  
>
> In the physical configuration I had TAF configured via tnsnames:
> ORCL =
>   (DESCRIPTION =
>     (ADDRESS =  (PROTOCOL = TCP)  (HOST = server1)  (PORT = 1521) )
>     (ADDRESS =  (PROTOCOL = TCP)  (HOST = server2)  (PORT = 1521) )
>     (CONNECT_DATA = (SERVICE_NAME=ORCL_PRIMARY)
>       (FAILOVER_MODE=  (TYPE=SELECT)  (RETRIES=1000)  (DELAY=60)
> (METHOD=BASIC) ) ) )
> and started the ORCL_PRIMARY service via a database startup trigger. In the 
> logical configuration I added a trigger to stop and start the service on 
> db_role_change. Both of these triggers function as expected.  
>
> The fact that the databases are not restarted on a logical standby 
> switchovermakes me wonder when TAF is supposed to occur. At no time does the 
> client session lose connection, which is the point at which it would be 
> redirected to the primary database service via tnsnames.  Even in the case 
> ofa logical standby failover the original primary database is still up and 
> running (albeit as a disabled standby) and connections persist.  It seems to 
> me that a restart of at least the logical standby is required to cause TAF. 
>
> This behaviour occurs not only via the application but also from a sqlplus 
> session on the database server, so it is not a client configuration issue.
> Active Dataguard is not an option as we are on 10g.
>
> Regards 
>
> Gerry
>
>
> CRISLER, JON A wrote: Are your clients configured with connect strings (jdbc 
> or tnsnames) where both primary and standby sides are defied? Also is your 
> app TAF compliant? And are you using Active Dataguard ? I suspect more a 
> client configuration issue. I have seen funny behavior like this when older 
> clients are connecting to new databases, or bugs in the client side. This is 
> why one should make sure that the client is upgraded to the same level as 
> thedb. We have numerous configurations on 10g Dataguard, 1 primary and 2 
> standby, and the sessions re-establish to the correct primary database- 
> however they are not TAF compliant so it requires a restart of the app.
> -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx[1] 
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx[2]] On Behalf Of Gerry Miller Sent:
> Friday, December 16, 2011 12:24 AM To: oracle-l@xxxxxxxxxxxxx[3] Subject:
> Switchover of Logical Standby database Hi I have had some experience with 
> physical standby databases and the Data Guard broker but have recently been 
> asked to implement a logical standby on 10.2.0.4 on Windows 2008 Server. I 
> was quite surprised to find that when a switchover or failover is performed 
> that the databases are not shutdown, which results in a faster operation.
> However, I was perturbed to find that any sessions that were originally on 
> the primary remained on the same database, that is, ended up on the standby 
> database, when I would have expected them to be on the new primary. Queries 
> can still be executed but any attempts at DML result in : "ORA-16224 
> DatabaseGuard is enabled". This seems an unlikely situation and I can't help 
> but feel that I must have something wrong with the configuration, although I 
> can't imagine that it would work at all if that were the case. Is this the 
> expected behaviour or should the sessions have transferred during the 
> switchover? Regards Gerry -- http://www.freelists.org/webpage/oracle-l[4] 
>
>
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