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From Tim Bain <tb...@alumni.duke.edu>
Subject Re: Can ActiveMQ take advantage of Oracle transparent application failover?
Date Wed, 26 Apr 2017 03:26:44 GMT
The JDBC store hasn't received as much attention as the KahaDB and LevelDB
stores, so it's not entirely surprising that you're seeing the same
behavior as that earlier post.

It sounds like you have an understanding of how an application is supposed
to interact with an Oracle TAF database in this scenario (and I'm not sure
whether any of the people who do ActiveMQ development do), so you could
write a feature request in JIRA to ask for the Oracle driver to behave in
the appropriate ways. However, asking the broker to reset back to a clean
state and attempt to start again may be more effort than people want to put
into it.

Luckily there's a workaround: start the ActiveMQ process in a loop that
will start a new process if the first one dies. You can write your own
shell script, or you may be able to use a third-party wrapper such as
Tanuki. (I don't have any experience with Tanuki, so I can't say for sure
that their wrapper will allow this behavior, but I think it does.)

I'm also concerned about the fact that the slave broker didn't acquire the
lock when the master died; that feels like a second, separate bug to enter
into JIRA, please. Please include any relevant log lines from the slave
broker that might explain why it didn't work as expected. If possible, it
would also be great to get a thread dump from the slave broker when the
master goes down, since that might help someone trace why the existing code
didn't work as expected.

Tim

On Apr 25, 2017 12:57 PM, "bsmith@skylinenet.net" <bsmith@skylinenet.net>
wrote:

> This question was posted May 16, 2011; 11:18am — by johanhonline johanh
> but
> I cannot locate any follow-up or resolution.
>
> Currently (04/25/2017) we have the same issue and I need to understand how
> to integrate Active MQ with Oracle 12.1.0.2 TAF (Transparent Application
> Failover) so that bouncing one node of the Oracle RAC doesn't break Active
> MQ as described in the original post below.
>
> I have read and understand the Oracle TAF documentation and combed through
> Active MQ lists.  Just need some input on how to get Active MQ to integrate
> with Oracle TAF.
>
> Any pointers to manuals/documentation or resources describing tests
> (successful or not) to get Active MQ to work with Oracle TAF are
> appreciated.
>
> Thanks
> -- bsmith@skylinenet.net
>
>
> johanh wrote
> > Hi list,
> >
> > We are currently running a master-slave cluster of ActiveMQ nodes, with a
> > JDBC persistence adapter backed by an Oracle 11g RAC database. This is
> > working fine from an ActiveMQ perspective; when the master goes down, a
> > slave automatically becomes the new master. However, we are having issues
> > when one of the database nodes goes down, and I am looking for ways to
> > have the ActiveMQ nodes handle this event as seamlessly as possible:
> > <snipped... Oracle TAF configuration...>
> > When one of the database nodes goes down, the master ActiveMQ node loses
> > its database lock, with the database returning an "ORA-25402: transaction
> > must roll back error". Per our DBA, this is normal behavior for Oracle
> > RAC, and is the Oracle OCI JDBC driver's cue to retry the connect.
> > However, this error causes the master ActiveMQ node to shut down
> entirely:
> > <snipped..>
> > After this, the earlier master node is completely shut down (the process
> > is no longer running), and none of the earlier slave nodes have taken
> over
> > as master. Restarting the master node ActiveMQ service makes it reacquire
> > the lock and become master again. Comparing these observations to what we
> > see in the database, it seems that the OCI driver is attempting to fail
> > over the connection to another database node (we can see some connections
> > from it failing over), but apparently that process gets interrupted by
> the
> > ActiveMQ master node shutting down per the above. Is there some way in
> > ActiveMQ to have the master node either attempt to reacquire the lock
> > itself, or wait for some time before shutting down, or is there some
> other
> > way in which database transparent application failover has been
> > implemented in ActiveMQ?
> >
> > Any advice appreciated!
> >
> > Regards,
> > Johan H
>
>
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Can-ActiveMQ-take-advantage-of-Oracle-transparent-application-
> failover-tp3526485p4725226.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

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