Page History

...

Introduction

MQTT Store and Forward allows data to be buffered locally at a client when connections are down to the MQTT Server infrastructure and deliver that data when the connection is restored. This feature is critical in most applications because if we lose connection to the MQTT Server we will lose data if it is not buffered locally. When Store and Forward is enabled and the edge node detects a disconnect to the MQTT Server, tags will be stored locally in a history store. When the edge node can reconnect to the MQTT Server, it will publish any stored tags. The rate at which these stored tags are flushed from the history store is configurable to prevent any delays in the delivery of live data.

...

Testing is the best way to determine your settings for your Edge Gateway(s) and the recommended approach is to:

• Configure a History Store with a large storage time for your tags.
• Disconnect the Edge for a set time period to cause MQTT Transmission to store data to the History Store using one of the methods detailed below:
  • Disable the network connection
  • Disable the broker
  • Use Primary Host ID in both MQTT Engine and in the MQTT Transmission.
    • Removing the Primary Host ID from MQTT Engine will simulate the primary backend application going offline and cause MQTT Transmission to store data to the History Store.
    • Restoring the Primary Host ID to MQTT Engine will simulate that the primary backend application is online and cause MQTT Transmission to flush the stored data
  • Modify the MQTT Transmission client credentials at the broker preventing the client from connecting

...