On Tue, Jun 14, 2011 at 12:45 PM, janne postilista <jannepostilis...@gmail.com> wrote: > I have routes that read from JMS queue and write to another queue and > do some processing in between. Queues are in external ActiveMQ server. > > I am confused about how error handling and configuring for example > retries is configured. > > - my route is marked <transacted/> and because of that, it uses > TransactionErrorHandler > - http://camel.apache.org/transactional-client.html states that > "Configuration of Redelivery: The redelivery in transacted mode is not > handled by Camel but by the backing system (the transaction manager). > In such cases you should resort to the backing system how to configure > the redelivery.". This I understand means that I configure "when > exceptions happen, delivery is tried 10 times before moving message to > dead letter queue" stuff to ActiveMQ, not Camel. > - http://camel.apache.org/transactionerrorhandler.html states that "As > the TransactionErrorHandler also supports to let Camel do redeliveries > you can use both worlds. Letting Camel do some redeliveries and at the > end the backing transaction manager doing other redeliveries. In fact > in the end the transaction manager have the final word. That means if > Camel cannot process the exchange then its thrown back to the > transaction manager that will perform the rollback, and redelivery.". > This I understand means means TransactionErrorHandler does it's own > redeliveries before ActiveMQ tries delivery? > > What if I configure 10 retries to both ActiveMQ and > TransactionalErrorHandler, is message processing retries 10*10 = 100 > times if it throws an exception? Is that how it works? >
Yes the TransactionErrorHandler used to not support Camel doing redelivery, but thats added now. When AMQ do redelivery, its a "all the way" redelivery, meaning when an error occurs, the entire exchange rolls back. And Camel will consume the message again - potentially using a new thread etc. There is no state shared between the redelivery attempts etc. Its only because AMQ put a flag on the message, that you know its a redelivery. JMSRedelivered. When Camel does redelivery, its a "fine grained" redelivery. As it retries "where the error occurred". So if you have: >From X to Y to Z and the error occur at "to Z" then it only retry at that point. However if AMQ does a redelivery, its "restarting". You can pick and chose. Buts its recommended to keep it KISS. -- Claus Ibsen ----------------- FuseSource Email: cib...@fusesource.com Web: http://fusesource.com Twitter: davsclaus, fusenews Blog: http://davsclaus.blogspot.com/ Author of Camel in Action: http://www.manning.com/ibsen/
