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@@ -1,57 +1,32 @@
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-EMQX Retainer
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-==============
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+# Retainer
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-The retainer plugin is responsible for storing retained MQTT messages.
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+The `emqx_retainer` application is responsible for storing retained MQTT messages.
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-Configuration
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--------------
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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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-etc/emqx_retainer.conf:
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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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+
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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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+ ```
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+retainer {
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+ enable = false
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+}
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```
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-## Where to store the retained messages.
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-## Notice that all nodes in a cluster are to have the same storage_type.
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-##
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-## Value: ram | disc
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-## - ram: memory only
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-## - disc: both memory and disc
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-##
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-## Default: ram
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-retainer.storage_type = ram
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-
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-## Maximum number of retained messages allowed.
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-##
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-## Value: Number >= 0
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-retainer.max_retained_messages = 1000000
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-
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-## Maximum payload size of a retained message.
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-##
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-## Value: Bytes
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-retainer.max_payload_size = 64KB
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-
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-## Expiration interval of the retained messages. Never expire if the value is 0.
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-##
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-## Value: Duration
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-## - h: hour
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-## - m: minute
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-## - s: second
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-##
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-## Examples:
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-## - 2h: 2 hours
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-## - 30m: 30 minutes
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-## - 20s: 20 seconds
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-##
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-## Default: 0
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-retainer.expiry_interval = 0
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-```
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-License
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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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+
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+## Contributing
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-Apache License Version 2.0
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+Please see our [contributing.md](../../CONTRIBUTING.md).
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-Author
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-------
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+## License
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-EMQX Team
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+See [LICENSE](../../APL.txt)
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Ilya Averyanov