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Use the tags below to verify the expected number of Edge Nodes have come online and remain online:

NodesOfflineIntegerThe number of Sparkplug Edge Nodes offline. This is determined by whether the last lifecycle message was an NBIRTH or NDEATH
NodesOnlineIntegerThe number of Sparkplug Edge Nodes online. This is determined by whether the last lifecycle message was an NBIRTH or NDEATH
NodeUnitCountIntegerThe total number of Sparkplug Edge Nodes as determined by the received NBIRTH messages


Use the tags below to identify the Sparkplug ID and last timestamp for the Offline and Online nodes

Offline NodesDatasetA dataset containing the Sparkplug ID and timestamp for all offline Sparkplug edge nodes
Online NodesDatasetA dataset containing the Sparkplug ID and timestamp for all online Sparkplug edge nodes 


Tip

Use the script below to easily parse the Offline and Online datasets

Code Block
languagepy
onlineEdgeNodes = system.dataset.toPyDataSet(system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/Online Nodes")[0].value)     
print "Online Sparkplug EdgeNodes: " + str(system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/NodesOnline")[0].value)
if system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/NodesOnline")[0].value > 0:
    for row in onlineEdgeNodes:
        data = []
        data.append(["Sparkplug EdgeNode Descriptor", row[0]])
        data.append(["Last Connect Date", row["Date"]])
        print data
         
offlineEdgeNodes = system.dataset.toPyDataSet(system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/Offline Nodes")[0].value)     
print "Offline Sparkplug EdgeNodes: " + str(system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/NodesOffline")[0].value)
if system.tag.readBlocking("[MQTT Engine]Engine Info/Edge Nodes/NodesOffline")[0].value > 0:
    for row in offlineEdgeNodes:
        data = []
        data.append(["Sparkplug EdgeNode Descriptor", row[0]])
        data.append(["Last Connect Date", row["Date"]])
        print data


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Engine Info - MQTT Clients



Server Latency (ms)IntegerThe amount of time that it takes for a test MQTT message to be sent and received back by MQTT Engine


Edge Node - Node Info Tags

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Using these tags we can look into the health of each Edge Node connection: 

Data Latency (ms)Long

The time in milliseconds between MQTT Engine receiving of the last message and the payload's reported time.

A long latency time can indicate network issues.

Note: For this to be very accurate the edge node's clock and the system clock running MQTT Engine should be synced


Birth Count

Long

The number of NBIRTH messages since the last time the info metrics were reset via the Node Info/Reset Info tag


Death CountLongThe number of NDEATH messages since the last time the info metrics were reset via the Node Info/Reset Info tag


Offline DateTimeDateTimeThe time at which the last NDEATH message was received by MQTT Engine


OnlineBooleanWhether or not the Edge Node is online. This is determined by whether the last lifecycle message was an NBIRTH or NDEATH


Online DateTimeDateTimeThe time at which the first NBIRTH message for a connection was received by MQTT Engine


Rebirth Requests

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(available 4.0.22 onward)

A high rebirth count in a small time window is a clear indicator of issues at the Edge(s).

In a Sparkplug compliant system, it is the combination of Group ID and Edge Node ID that identifies the Edge Node and is the 'Sparkplug Edge Node Descriptor'.

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 Every Sparkplug Edge Node Descriptor within a Sparkplug environment must be unique because these are used as 'addresses' in the system to identify the edge node.

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If there are two or more Transmitters with the same Sparkplug Edge Node Descriptor data from these two transmitters will sent with the same topic resulting in the next message sequence number expected by the MQTT client being incorrect.

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 As a result, the MQTT Client will mark the data as stale and request a rebirth from the transmitter.

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If you have multiple MQTT Clients subscribing to the namespace, this will also likely create a firestorm of rebirth requests across the system.


Rebirth (Last) CauseString

The reason for the last rebirth request

(available 4.0.22 onward)Reasons

. Reasons are:

  • Triggered by
User
  • user
  • Message sequence number error
  • Received a message for edge node that is offline


Rebirth (Last DateTime)DateTimeThe time of the last rebirth request issued by MQTT Engine
(available 4.0.22 onward)


Rebirth CountInteger

The count of rebirth requests issued by MQTT Engine

(available 4.0.22 onward)A high rebirth count in a small time window is a clear indicator of issues at the Edge.