Setting an Acknowledgement Mode for an MQTT Trigger
The acknowledgement mode determines when a message received by an MQTT trigger is acknowledged to the MQTT server. The message can be acknowledged as soon as the message arrives (automatic acknowledgement) or after message processing completes (client acknowledgement).
If the connection between Integration Server and the MQTT server becomes unavailable, any persisted messages that the MQTT trigger received but did not acknowledged, should be redelivered by the MQTT server when the connection is re-established. If MQTT trigger sent an acknowledgement for a persisted message but the connection failed before the MQTT server received the acknowledgement, the MQTT server should redeliver the message when the connection is re-established.
Note:
The MQTT server can redeliver a persisted message only. A persisted message has an overall QoS of 1 or 2 where overall refers to the lower of the QoS levels assigned to the publishing of the message or the receiving of the message. If the QoS for message publishing or retrieval is 0, the message cannot be recovered. Additionally, the MQTT connection alias used by the trigger must not use clean sessions.
To set the acknowledgement mode for an MQTT trigger
1. In the Package Navigator view of Designer, open the MQTT trigger for which you want to set the acknowledgment mode.
2. In the Properties view, under General, set the Acknowledgement mode property to one of the following:
Acknowledgement mode | Description |
Client Acknowledgement | The MQTT trigger acknowledges a message to the MQTT server after completing processing for the message. This is the default. Note: If you intend to use the Stop trigger retry failure handling option for the MQTT trigger, select Client Acknowledgement. This makes it possible for the MQTT server to redeliver the message after retry failure occurs. If the MQTT trigger uses Auto Acknowledgement, the message is acknowledged upon receipt which is before retry failure occurs. |
Auto Acknowledgement | The MQTT trigger acknowledges a message to the MQTT server as soon as the message arrives. |
3. Click File > Save.