S&F Functionality For Remote MQTT Publisher
The Publisher service is a great bit of data connectivity for Canary, but it is missing a key feature. In distributed architectures, you cannot be sure that an MQTT stream won't miss any TVQs if there is a brief connection loss between the Publisher service and the Views service, or the Views services and the Historian. This makes MQTT architectures with Canary extremely brittle.
I don't know enough about how the internal connections work, but it would be great to be able to check "Store and Forward" boxes on the Views/Historian connections, and on new Publishers to enable buffering (or even just buffer by default?).
Please someone let me know if there is already a way to solve this problem!
1 reply
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Hi ,
There is a Durable Stream option which uses the Historian as a buffer in the case of outages. It is designed to send every update since the last publish. In the case of a disconnect, or the Publisher is shut off, it will "backfill" when it comes back online. There is a potential it will republish data that has already been sent in these circumstances as it saves its state every 30 seconds. So at most, you would republish up to 30 seconds of data depending on where the disconnect occurs. This Durable Stream option is not intended for high volume throughput, less than 10k updates per second.
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