ActiveMQ : dead letter queue keeps my messages order

Question

Hi,

I use ActiveMQ as a broker to deliver messages. Theses messages are intented to be written in a dabatase. Sometimes, the database is unreachable or down. In that case, I want to rollback my message to retry later this message and I want to continue reading other messages.

This code works fine, except one point : the rollbacked message is blocking me from reading the others :

private Connection getConnection() throws JMSException {
    RedeliveryPolicy redeliveryPolicy = new RedeliveryPolicy();
    redeliveryPolicy.setMaximumRedeliveries(3); // will retry 3 times to dequeue rollbacked messages
    redeliveryPolicy.setInitialRedeliveryDelay(5 *1000);  // will wait 5s to read that message

    ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(user, password, url);
    Connection connection = connectionFactory.createConnection();
    ((ActiveMQConnection)connection).setUseAsyncSend(true);
    ((ActiveMQConnection)connection).setDispatchAsync(true);
    ((ActiveMQConnection)connection).setRedeliveryPolicy(redeliveryPolicy);
    ((ActiveMQConnection)connection).setStatsEnabled(true);
    connection.setClientID("myClientID");
    return connection;
}

I create my session this way :

session = connection.createSession(true, Session.SESSION_TRANSACTED);

Rollback is easy to ask :

session.rollback();

Let's imagine I have 3 messages in my queue :

1: ok
2: KO (will need to be treated again : the message I want to rollback)
3: ok
4: ok

My consumer will do (linear sequence) :

commit 1 
rollback 2
wait 5s
rollback 2
wait 5s
rollback 2
put 2 in dead letter queue (ActiveMQ.DLQ)
commit 3
commit 4

But I want :

commit 1
rollback 2
commit 3
commit 4
wait 5s
rollback 2
wait 5s
rollback 2
wait 5s
put 2 in dead letter queue (ActiveMQ.DLQ)

So, how can I configure my Consumer to delay my rollbacked messages later ?

Answer 1

Are you using the <strictOrderDispatchPolicy /> in the ActiveMQ XML config file? I'm not sure if this will affect the order of messages for redelivery or not. If you are using strict order dispatch, try commenting out that policy to see if that changes the behavior.

Bruce