Throttle config option to disable "key" label in events_discarded_total metric

[Hexta]

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Use Cases

Currently, throttle exposes every bucket as a key label in events_discarded_total metric:

events_discarded_total{key="value1"} 
events_discarded_total{key="value2"} 
...
events_discarded_total{key="valueN"} 

Using key_field with an unrestricted range of values (-Inf, +Inf) leads in cardinality explosion.

Attempted Solutions

filter and tag_cardinality_limity transforms could help reduce cardinality at the output.
However, utilisation of these transforms will continue to increase proportionately to internal metrics cardinality.

Proposal

Implement a configuration option for throttle transform to disable key label in the metrics.

References

No response

Version

0.30.0

[dsmith3197]

Note that there have been prior discussions on whether or not to drop the key label altogether here.