I am trying to get my Spring 4 JMS application to dynamically scale down after a lot of messages were processed. I currently have a concurrency of 1-3 consumers and I am able to see a successful scaling up toward the maximum consumers, but once the consumers have been created, they don't go away. They stay there in a WAIT state. I would like to know if there is a setting or configuration that enables the consumers to shutdown after the load subsides. Does anyone know?
Thanks,
Juan
Take a look to this option:
/**
* Specify the limit for idle executions of a consumer task, not having
* received any message within its execution. If this limit is reached,
* the task will shut down and leave receiving to other executing tasks.
* <p>The default is 1, closing idle resources early once a task didn't
* receive a message. This applies to dynamic scheduling only; see the
* {@link #setMaxConcurrentConsumers "maxConcurrentConsumers"} setting.
* The minimum number of consumers
* (see {@link #setConcurrentConsumers "concurrentConsumers"})
* will be kept around until shutdown in any case.
* <p>Within each task execution, a number of message reception attempts
* (according to the "maxMessagesPerTask" setting) will each wait for an incoming
* message (according to the "receiveTimeout" setting). If all of those receive
* attempts in a given task return without a message, the task is considered
* idle with respect to received messages. Such a task may still be rescheduled;
* however, once it reached the specified "idleTaskExecutionLimit", it will
* shut down (in case of dynamic scaling).
* <p>Raise this limit if you encounter too frequent scaling up and down.
* With this limit being higher, an idle consumer will be kept around longer,
* avoiding the restart of a consumer once a new load of messages comes in.
* Alternatively, specify a higher "maxMessagesPerTask" and/or "receiveTimeout" value,
* which will also lead to idle consumers being kept around for a longer time
* (while also increasing the average execution time of each scheduled task).
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
* @see #setMaxMessagesPerTask
* @see #setReceiveTimeout
*/
public void setIdleTaskExecutionLimit(int idleTaskExecutionLimit) {
Also you can study all other options of the DefaultMessageListenerContainer via their JavaDocs.