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clean session

A connection where the broker forgets everything about the client when it disconnects.

With a clean session the broker discards the client's subscriptions and queued messages when it disconnects, so every connect starts empty.

Examples

  • A dashboard that only shows live readings can use a clean session: when it disconnects, the broker forgets its subscriptions.

  • A client on a clean session that is offline for an hour misses every QoS 1 message published during that hour.

See also

persistent session client ID quality of service
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