Does the Cardinality Limiter really limit a tag values?

[sokyrynskyi]

There is the Cardinality Limiter that allows only a limited number of values for the gql.operation.name tag, replacing the rest values with --others--.

As I see it's implemented as a ConcurrentHashMap (from the Spectator).

Does it mean that:

1. If I have N instances reporting the metric, there might be more values than the limit (since the limit is applied to an instance and it's possible to have a different operations' rate on different instances due to routing policies).
2. When instances are frequently restarted, a Limiter's storage is frequently emptied, which again leads to reporting more values than the limit. F.e. the FirstLimiter or MostFrequentLimiter is filled with different "top 100" queries between reboots.

?

Thanks in advance for the explanation, it's possible I misunderstand the concept 😕