33 lines
1.3 KiB
Markdown
33 lines
1.3 KiB
Markdown
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# Retainer
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The `emqx_retainer` application is responsible for storing retained MQTT messages.
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The retained messages are messages associated with a topic that are stored on the broker and delivered to any new subscribers to that topic.
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More information about retained messages can be found in the following resources
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* [MQTT specification 3.3.1.3](http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html).
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* Retained message concept in [EMQX documentation](https://www.emqx.io/docs/en/v5.0/messaging/mqtt-concepts.html#retained-message).
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* Instructions for publishing retained messages in [EMQX documentation](https://www.emqx.io/docs/en/v5.0/messaging/mqtt-retained-message.html#publish-retained-message-with-mqttx-client).
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* [The Beginner's Guide to MQTT Retained Messages](https://www.emqx.com/en/blog/mqtt5-features-retain-message).
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## Usage
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The `emqx_retainer` application is enabled by default. To turn it off, add the following configuration to the `emqx.conf` file:
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```
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retainer {
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enable = false
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}
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```
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For other options, see the [configuration](https://www.emqx.io/docs/en/v5.2/configuration/configuration-manual.html#retainer) documentation.
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## Contributing
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Please see our [contributing.md](../../CONTRIBUTING.md).
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## License
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See [LICENSE](../../APL.txt)
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