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https://issues.apache.org/jira/browse/AMQ-6603?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15887117#comment-15887117
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Tadayoshi Sato commented on AMQ-6603:
-------------------------------------
Hi [~cshannon],
Thank you for your comments, and sorry for my late response.
{quote}
I think the issue is with your configuration. It usually doesn't make sense to
use a connection pool with a DefaultMessageLIstenerContainer because you want
to let the DefaultMessageListenerContainer do its own caching.
{quote}
I can see your point, but one itchy situation about it is that Apache Camel has
long been promoting the combination of {{PooledConnectionFactory}} + DMLC as
the best practice ({{camel-jms}} is effectively just a DMLC inside).
http://camel.apache.org/activemq.html#ActiveMQ-Usingconnectionpooling
We could say that Apache Camel has been wrong on this, but please note that the
issue happens only when a {{failover:\(...)}} broker URL is used with
{{ActiveMQConnectionFactory}} and for a plain {{tcp://...}} URL we see no
issues even with the above combination. That's why I think there might be
something that can be improved in ActiveMQ side (especially between
{{PooledConnectionFactory}} and Failover transport).
Or we could instead argue that the specific combination of Failover transport +
PooledConnectionFactory + DMLC is evil; in this case, what do you think would
be the correct configuration if users need to use Failover transport?
{quote}
If you just pass a normal connection factory to the
DefaultMessageListenerContainer then it should just create 1 connection and 10
consumers.
{quote}
Yes, but then doesn't the number of connection instances grow proportionately
to the number of DMLC instances used? I think that's why people want to use
{{PooledConnectionFactory}} in combination with DMLC (or {{camel-jms}}).
{quote}
Also you said you could reproduce it without using Spring DMLC. What was your
setup in that case?
{quote}
Attached {{pooled-amq-client.zip}} is a reproducer that doesn't use DMLC. I
admit it's rather a contrived example and mostly just mimics what's being done
inside DMLC, but it still reproduces the issue with only ActiveMQ.
> Excessive number of consumers when used with PooledConnectionFactory and
> Failover transport
> -------------------------------------------------------------------------------------------
>
> Key: AMQ-6603
> URL: https://issues.apache.org/jira/browse/AMQ-6603
> Project: ActiveMQ
> Issue Type: Bug
> Components: JMS client
> Affects Versions: 5.14.3
> Reporter: Tadayoshi Sato
> Attachments: pooled-amq-client.zip, spring-amq-client.zip
>
>
> When {{PooledConnectionFactory}} is used with Failover transport,
> insufficient access control settings on the broker result in an excessive
> number of consumer objects on the broker once the access control settings are
> properly set.
> Here is an example Spring XML configuration:
> {code:xml}
> <beans ...>
> <bean id="jmsConnectionFactory"
> class="org.apache.activemq.ActiveMQConnectionFactory">
> <property name="brokerURL" value="failover:(tcp://localhost:61616)" />
> <property name="userName" value="test" />
> <property name="password" value="test" />
> </bean>
> <bean id="pooledConnectionFactory"
> class="org.apache.activemq.pool.PooledConnectionFactory">
> <property name="connectionFactory" ref="jmsConnectionFactory" />
> <property name="maxConnections" value="10" />
> </bean>
> <bean id="jmsContainer"
> class="org.springframework.jms.listener.DefaultMessageListenerContainer">
> <property name="connectionFactory" ref="pooledConnectionFactory" />
> <property name="destinationName" value="TEST" />
> <property name="messageListener" ref="messageListener" />
> <property name="concurrentConsumers" value="10" />
> </bean>
> <bean id="messageListener" class="com.redhat.issues.amq.SpringJmsConsumer"
> />
> </beans>
> {code}
> In this configuration we expect only one connection and 10 consumers for
> {{TEST}} queue, but after following the reproducer steps we see around 10
> connections and 100 consumers for the queue on hawtio. In the above
> configuration Spring DMLC is used but we can reproduce the issue without
> Spring.
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