Deviations
Deviations surface what is happening across your Unified Namespace. The most important events are deviations: traffic that does not match the structure and data types you defined in Contextualize.
Deviations are detected on the tags and assets that carry payloads, and are listed per broker, so you can see exactly where a governed stream drifts from its definition.
| In the HiveMQ Platform, deviations appear on the Deviations tab of Analyze, alongside Data Health. |
Review Deviations per Broker
First, use the broker selector to choose the broker whose events you want to see. The Deviations tab then lists every deviation detected on that broker’s traffic. You can filter the list and switch between Active deviations and ones you have Ignored.
Each row describes one deviation:
| Column | Description |
|---|---|
Node |
The tag or asset whose traffic deviates — for example, a |
Agent |
The connected broker that detected and reported the deviation. |
Issue Type |
The kind of deviation, such as Unexpected Format. See Deviation Types. |
Count |
How many times the deviation has occurred. |
Last Occurrence |
When the deviation was most recently observed. |
Actions |
Open the deviation Details, view the tag or asset in the namespace, ignore the deviation, or remove it. |
Inspect a Deviation
Select Details on a deviation to open the Deviation Details view, which shows the full context and the payloads that caused it.
The details view shows:
| Field | Description |
|---|---|
Namespace |
The breadcrumb path of the tag or asset — for example, |
MQTT Topic |
The full MQTT topic the deviating traffic flows on. |
Issue Type |
The kind of deviation. See Deviation Types. |
Occurrence Count |
How many times the deviation has occurred. |
Last Occurred |
When the deviation was most recently observed. |
Expected Data Type |
The data type the tag or asset expects — for example, |
Last Valid Payload |
The most recent payload that matched the definition — for example, |
Incorrect Payload |
The payload that triggered the deviation — for example, |
Comparing the Last Valid Payload with the Incorrect Payload makes the impact concrete.
In this example, the temperature tag is expected to be a Decimal such as 24.0, but is sometimes sent as a string that includes the Celsius sign, such as 23.6C.
That string does not match the expected format, so it is reported as an Unexpected Format deviation.
The details view also provides actions to View in Namespace (jump to the tag or asset), Ignore the deviation, or Remove it.
Ignore Deviations
Not every deviation needs action. When a deviation is expected or acceptable — for example, a legacy device you plan to migrate later — you can ignore it so it no longer clutters the active list.
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To ignore a deviation, select Ignore on the deviation row or in its Details view.
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Ignored deviations move out of the Active list. Switch the toggle from Active to Ignored to review everything you have suppressed.
Ignoring is remembered per tag or asset and deviation type: while an ignore is in place, matching deviations on that tag or asset are kept out of the active list.
To stop ignoring a deviation, open the Ignored list and delete it there. This removes the ignore rule, so if the same issue occurs again it is detected and shown as Active once more.
| Ignore suppresses a deviation while keeping a record of it, whereas Remove deletes an active deviation outright. A removed deviation is detected again if the underlying issue recurs. |
Deviation Types
A deviation is always one of the following types:
| Issue Type | Description |
|---|---|
Missing Field |
A field defined for the tag or asset in the namespace is not present in the payload. |
Unexpected Field |
The payload contains a field that is not defined for the tag or asset in the namespace. |
Unexpected Format |
A value does not match the expected data type or format — for example, a value expected as a |