Maybe I need to narrow my questions:
1) Why would CACHE_SESSION on the ActiveMQComponent cause endless external
redeliveries of a (filtered out) topic message, when with other cache
settings this does not occur?
2) Why would <rollback/> prevent the external redeliveries, but <stop/>
does not prevent them?
Did I provide enough info below to answer these questions? Topics just
aren't working in Camel the way that I would expect!
Thanks,
Jeff Bischoff
WDTS
On 5/29/14 4:25 PM, "Jeff Bischoff" <jbisch...@wdtablesystems.com> wrote:
>Hi all,
>
>Please forgive me if this is a basic question.
>
>Working with Camel and JMS Topics has seemed very finicky for me so far.
>If I make slight configuration changes, I see the same message repeated
>endlessly. Using jconsole, I now know these messages are "external
>redeliveries", i.e. the same message is being sent from JMS to Camel
>repeatedly without ever getting through. It happens in the case of
>messages that I am intentionally not processing due to some criteria.
>What I don't understand is why these external redeliveries keep
>occurring, when I simply want this message to be dropped.
>
>For example, if I use CACHE_SESSION or lower cache level, the following
>route works just fine for me:
>
>
> <route id="topics-out">
> <from uri="topic-jms:topic:projectx.>"/>
> <log message="Picked up message with id: ${id},
>destinationType: ${header.DestinationEntityType}" loggingLevel="INFO"/>
> <choice>
> <when>
> <simple>${header.DestinationEntityType} not in
>'FOO,BAR'</simple>
> <log message="Detected new ${header.Name} topic
>message on ${header.JMSDestination} with id: ${id}, destinationType:
>${header.DestinationEntityType}" loggingLevel="INFO"/>
> <recipientList ignoreInvalidEndpoints="false">
> <simple>lc-jms:${header.JMSDestination}</simple>
> </recipientList>
> </when>
> </choice>
> </route>
>
>
>However, if I switch to CACHE_CONSUMER and I have even one message
>addressed to 'FOO' or 'BAR', I will see the endless external
>redeliveries. Note that I am using a SingleConnectionFactory specifically
>for this route.
>
> <route id="topics-out">
> <from uri="topic-jms:topic:projectx.>"/>
> <log message="Picked up message with id: ${id},
>destinationType: ${header.DestinationEntityType}" loggingLevel="INFO"/>
> <choice>
> <when>
> <simple>${header.DestinationEntityType} not in
>'FOO,BAR'</simple>
> <log message="Detected new ${header.Name} topic
>message on ${header.JMSDestination} with id: ${id}, destinationType:
>${header.DestinationEntityType}" loggingLevel="INFO"/>
> <recipientList ignoreInvalidEndpoints="false">
> <simple>lc-jms:${header.JMSDestination}</simple>
> </recipientList>
> </when>
> </choice>
> </route>
>
>Now, if I add an Otherwise clause with a Rollback, everything works fine
>again (albeit with a handful of log messages due to the rollbacks):
>
> <route id="topics-out">
> <from uri="topic-jms:topic:projectx.>"/>
> <log message="Picked up message with id: ${id},
>destinationType: ${header.DestinationEntityType}" loggingLevel="INFO"/>
> <choice>
> <when>
> <simple>${header.DestinationEntityType} not in
>'FOO,BAR'</simple>
> <log message="Detected new ${header.Name} topic
>message on ${header.JMSDestination} with id: ${id}, destinationType:
>${header.DestinationEntityType}" loggingLevel="INFO"/>
> <recipientList ignoreInvalidEndpoints="false">
> <simple>lc-jms:${header.JMSDestination}</simple>
> </recipientList>
> </when>
> <otherwise>
> <rollback markRollbackOnly="true" />
> </otherwise>
> </choice>
> </route>
>
>But if I change that Rollback to a Stop instead, I get the endless
>external redeliveries again:
>
> <route id="topics-out">
> <from uri="topic-jms:topic:projectx.>"/>
> <log message="Picked up message with id: ${id},
>destinationType: ${header.DestinationEntityType}" loggingLevel="INFO"/>
> <choice>
> <when>
> <simple>${header.DestinationEntityType} not in
>'FOO,BAR'</simple>
> <log message="Detected new ${header.Name} topic
>message on ${header.JMSDestination} with id: ${id}, destinationType:
>${header.DestinationEntityType}" loggingLevel="INFO"/>
> <recipientList ignoreInvalidEndpoints="false">
> <simple>lc-jms:${header.JMSDestination}</simple>
> </recipientList>
> </when>
> <otherwise>
> <stop/>
> </otherwise>
> </choice>
> </route>
>
>Why does rolling back prevent the unwanted message from being
>redelivered, while using "stop" causes the redelivery to occur?
>Intuitively, I would have thought it would work the opposite way. Rolling
>back should put the item back on the "from" endpoint, allowing it to be
>processed again. "Stop" should just drop the message, preventing further
>redelivery. What I'm actually seeing is the opposite of this. Am I
>misunderstanding?
>
>I also get the same exact symptoms if I leave the cache level at
>CACHE_SESSION, but I make the subscription durable. In that case the
>rollbacks prevent the problem, but otherwise I get the eternal external
>redeliveries.
>
>Using a Filter element also produces the same results as using the Choice
>element above:
>
> <route id="topics-out">
> <from
>uri="topic-jms:topic:projectx.>?durableSubscriptionName=testdurasub"/>
> <log message="Picked up message with id: ${id},
>destinationType: ${header.DestinationEntityType}" loggingLevel="INFO"/>
> <filter>
> <simple>${header.DestinationEntityType} not in
>'FOO,BAR'</simple>
> <recipientList ignoreInvalidEndpoints="false">
> <simple>lc-jms:${header.JMSDestination}</simple>
> </recipientList>
> </filter>
> </route>
>
>When I look at the topic in JMS, I see the topic "projectx.>" appearing
>and disappearing in the list rapidly. I assume that's caused by the Camel
>polling frequency. It seems a little disturbing to me; is that normal?
>
>Thanks so much for taking the time to help!
>
>Jeff Bischoff
>WDTS
