4 Replies Latest reply on Dec 14, 2011 8:53 AM by gilstr

Prevent receiving a message multiple times

gilstr Dec 14, 2011 7:43 AM

Hello

I'm having a producer client which is required to send an ack for each message it receives. Is it possible that the client will be receiving the same massage more than once. An example for such a scenario I can think of is:

- HornetQ publishes a message and wait for ack

- consumer client receives message and send ack

- network failure - HornetQ does not receive ack

- HornetQ resend message

- client receive the same message again

Is there a mechanism (such as nonce) that can prevent the second message from being received in the client or this is something I should implement in the application level?

Thanks,

Gil

1. Re: Prevent receiving a message multiple times

gaohoward Dec 14, 2011 7:55 AM (in response to gilstr)

Can I ask why you don't want the message being redelivered in case of failure?
Actions
2. Re: Prevent receiving a message multiple times

gilstr Dec 14, 2011 7:59 AM (in response to gaohoward)

Hi

Suppose that a producer sends a consumer a money transfer order message. That message is propogated from HornetQ to the consumer which does receive it but the ack is not received to HornetQ, which will cause a the latter to re-send the money transfer order. In such a scenario (without message duplication prevention mechanism) the consumer will process the money transfer order twice instead of once.

I hope that I was able to make it clear enough.

Thanks,

Gil
Actions
3. Re: Prevent receiving a message multiple times

gaohoward Dec 14, 2011 8:10 AM (in response to gilstr)

I think what you need is transactional receive. You can wrap the message receiving and money transfer in one transaction. If the ack failed the transaction will be rolled back.

Howard
1 of 1 people found this helpful
Actions
4. Re: Prevent receiving a message multiple times

gilstr Dec 14, 2011 8:53 AM (in response to gaohoward)

I appreciate your help.

Gil
Actions

Go to original post