ActiveMQ Topic to Queue，当从Master切换到Slave时使用Camel路由消息丢失？

Question

The setup: Default ActiveMQ.XML. One ActiveMQ instance per server on 3 Servers at Local data-center, One ActiveMQ instance at a remote data-center Server. All 3 + 1 instances are running, but only one ActiveMQ instance is the master at any given moment per data-center. Messages from all instances at all data-centers are persistent to a network KahaDB, and we've configured two retries per message.

The goal: To keep the queues synchronized between data-centers.

The problem: To test when the remote server is down, that all messages will be saved/persisted until the remote server is back online. I will send three messages to an ActiveMQ Topic.

A camel route is configured to read from the topic and push to 2 local queues.

A second camel route is setup to read from one of the local queues, and push the message to a remote ActiveMQ.

When the remote server is off (data-center 2 is down), and we fail over from the Master ActiveMQ (by stopping the service) to a slave, 1 out of the 3 messages is lost to the ether. It seems to be the first message that's sent to the remote server. As if it's getting a connection refused or something, and it disappears forever, not even going into the DLQ?

The camel configuration:

<bean id="local" class="org.apache.activemq.camel.component.ActiveMQComponent">
  <property name="brokerURL" value="tcp://localhost:12345"/>
  <property name="preserveMessageQos" value="true" />
</bean>

<bean id="remote" class="org.apache.activemq.camel.component.ActiveMQComponent">
  <property name="brokerURL" value="failover:(tcp://remotehost:54321)"/>
  <property name="preserveMessageQos" value="true" />
</bean>

<camelContext id="topicToQueueCamelContext" xmlns="http://camel.apache.org/schema/spring">
    <route id="topicToQueue">
        <from uri="local:topic:SomeTopic"/>
        <to uri="local:queue:SomeQueue"/>
        <to uri="local:queue:SomeQueue.Remote"/>
    </route>
</camelContext>

<camelContext id="queueToRemoteQueueCamelContext" xmlns="http://camel.apache.org/schema/spring">
    <route id="queueToRemoteQueue">
        <from uri="local:queue:SomeQueue.Remote"/>
        <to uri="remote:queue:SomeQueue"/>
    </route>
</camelContext>

Tried: Setting the remote camel routes as transacted, and setting trackMessages=true on the brokerURL Failover Transport.

Does anyone have any ideas on which ActiveMQ BrokerURL, ActiveMQ XML, or Camel URI Query String Parameters might be missing -- or any ideas on how to solve or debug this missing message problem?

Answer 1

You need to configure your ActiveMQComponent to consume messages transactional . By default message consumption is not transactional. That way you get the best performance, but you also "accept" to lose messages.