23 lines
1.7 KiB
Markdown
23 lines
1.7 KiB
Markdown
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# Delayed Redelivery Example
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To run the example, simply type **mvn verify** from this directory, or **mvn -PnoServer verify** if you want to start and create the broker manually.
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This example demonstrates how ActiveMQ Artemis can be configured to provide a delayed redelivery in the case where a message needs to be redelivered.
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Delaying redelivery can often be useful in the case that clients regularly fail or roll-back. Without a delayed redelivery, the system can get into a "thrashing" state, with delivery being attempted, the client rolling back, and delivery being re-attempted ad infinitum in quick succession, using up valuable CPU and network resources.
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Re-delivery occurs when the session is closed with unacknowledged messages. The unacknowledged messages will be redelivered.
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By providing a redelivery delay, it can be specified that a delay of, say, 10 seconds is implemented between rollback and redelivery. The specific delay is configurable on both a global and per destination level, by using wild-card matching on the address settings.
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## Example setup
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Redelivery delay is specified in the configuration file [broker.xml](src/main/resources/activemq/server0/broker.xml):
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In this example we set the redelivery delay to 5 seconds for the specific example queue. We could set redelivery delay on on multiple queues by specifying a wild-card in the match, e.g. `match="jms.#"` would apply the settings to all JMS queues and topics.
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We then consume a message in a transacted session, and rollback, and note that the message is not redelivered until after 5 seconds.
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<address-setting match="exampleQueue">
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<redelivery-delay>5000</redelivery-delay>
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</address-setting>
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