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Tag Archives: Apache ActiveMQ

Temp, Store and Memory Percent Usage in ActiveMQ

In order to effectively use ActiveMQ, it is very important to understand how ActiveMQ manages memory and disk resources to handle non-persistent and persistent messages. ActiveMQ has three key parameters which need to be kept under check. Temp Percent Usage This is the % of assigned disk storage that has been used up to spool non-persistent messages Non persistent messages ...

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Running multiple ActiveMQ instances on one machine

A few weeks ago I started making use of Apache ActiveMQ again as the JMS provider with my Mule ESB solution. Since it had been a few years that I used ActiveMQ I thought it would be nice to check out some of the (new) features like the failover transport and other clustering features. To be able to test these ...

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Apache ActiveMQ 5.9 released

The Apache ActiveMQ team has just released the new ActiveMQ 5.9 release. This release is 8 months of hard work since the previous 5.8 release. In this release we have as usual more hardening of the broker, and the recent new protocols such as AMQP and MQTT. Also very interesting is the hardening of the leveldb persistent store, which now ...

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Apache Camel Broker Component for ActiveMQ 5.9

Embedding Apache Camel inside the ActiveMQ broker provides great flexibility for extending the message broker with the integration power of Camel. Apache Camel routes also benefit in that you can avoid  the serialization and network costs of connecting to ActiveMQ remotely – if you use the activemq component. One of the really great things about Apache ActiveMQ is that it ...

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ActiveMQ Message Priorities: How it works

There’s usually a steady drip of questions on the mailing list surrounding ActiveMQ’s message-priority support as well as good questions about observed behaviors and “what’s really supported”? I hope to help you understand what happens under the covers and what levels of priority can be supported. The details could get gory for some. If you’re not interested in the details, ...

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ActiveMQ: Understanding Memory Usage

As indicated by some recent mailing list emails and a lot of info returned from Google, ActiveMQ’s SystemUsage and particularly the MemoryUsage functionality has left some people confused. I’ll try to explain some details around MemoryUsage that might be helpful in understanding how it works. I won’t cover StoreUsage and TempUsage as my colleauges have covered those in some depth. ...

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Guaranteed messaging for topics, the JMS spec, and ActiveMQ

Recently a customer asked me to look closer at ActiveMQ’s implementation of “persistent” messages, how it applies to topics, and what happens in failover scenarios when there are non-durable subscribers. I had understood that the JMS semantics specify that only durable subscribers to a topic are guaranteed message delivery for a persistent delivery mode, even in the face of message-broker ...

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