What is the practical consequence of importing Prometheus metrics that carry a label with unbounded values, such as a request identifier?
Select an answer to reveal the explanation.
Short Explanation
You create one time series per distinct value. A request-ID label turns one metric into millions, blowing up storage and queries.
Full Explanation
The correct choice is the one stating that one time series is created per distinct value, causing a cardinality explosion that consumes storage and degrades query performance. Time-series systems key data by the full set of label values, so an unbounded label produces effectively unlimited series. This is the classic cardinality failure and it degrades both storage and query behaviour.
The choice claiming the metric is silently converted into a trace by the backend is incorrect because metrics and traces are separate data types and no such conversion occurs.
The choice claiming the label is discarded and the metric loses all of its dimensions is incorrect because labels are preserved rather than silently dropped, which is precisely why cardinality grows.
The choice claiming the metric is stored once and the label values are averaged together is incorrect because label values are not averaged; distinct values create distinct series.
For the exam, recognise unbounded label values as the cause of cardinality explosion.