[sparkplug-wg] Does Ignition honor payload/metric is_transient flag?

[Leland Falde <leland.falde@xxxxxxxxxxxxxxx>]

Good afternoon sparkplug working group. It’s an honor to post my first question here today 😊.

 

• All stars aligned for MQTT and Ignition.
• Successfully storing historical tags to an MySQL db.
• Everything looks great.
• I am very new to MQTT/Sparkplug/Ignition.

 

The MQTT to Ignition mapping appears to honor the is_null flag.

With an Ignition MQTT Engine configuration change, Ignition appears to honor the is_historical flag and bypasses the Tag update.

It appears to not honor or have a way to utilize the is_transient flag.

 

Question: Does Ignition honor the is_transient flag for its intended use case within Sparkplug specification?

I don’t see natively where Ignition has a similar flag that can be used to indicate that Ignition should not store this particular metric.

 

I will post this to Cirrus Link and Ignition directly, but I sense a better chance of someone here already knows the answer.

 

Research:
https://docs.chariot.io/display/CLD79/FAQ%3A+Sparkplug

I did find this…but its referring to a Template which I’m not sure of its relevance to a DDATA metric.

 

Sincerely,

 

Leland Falde

 

 

Our use case.

 

We publish EventStart (where 20% of metrics are set)
We publish EventIntraData (where 20% more of metrics are changing)

We publish EventEnd (where 100% of metrics are finally set)

 

EventStart:

 

Topic	Topic (cont)	Start	Intra (every .1 sec)	End
		Is_transient = true	Is_transient = true	Is_transient = false
spBv1.0/group1/DBIRTH/node1/device1/	eventName/Start	Set
	eventName/End			Set
	eventName/Number	Set
	eventName/Metric1	Set	Updated	Updated
	eventName/Metric2	Set	Updated	Updated
	eventName/Metric3	Set	Updated	Updated
	… aggregates/results			Set
	eventName/t_stamp

 

I am sending the complete eventName/{metricset} at EventEnd…with a new matching t_stamp for all metrics.

I was hoping that the Ignition system would update the live tags for is_transient = true…but not take into consideration for historian.

 

My current course of action, unless I learn something different from this mailing group, is to separate the Start/Intra/End into an EventStatus topic and publish the EventReport at End.

 

Leland D. Falde

Senior Software Developer

 

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