As per the specs, there are 3 ways to configure cardinality limit:

The cardinality limit for an aggregation is defined in one of three ways:

• A view with criteria matching the instrument an aggregation is created for has an aggregation_cardinality_limit value defined for the stream, that value SHOULD be used.
• If there is no matching view, but the MetricReader defines a default cardinality limit value based on the instrument an aggregation is created for, that value SHOULD be used.
• If none of the previous values are defined, the default value of 2000 SHOULD be used.

The implementation currently imposes the limit to be 2000. And the measurement beyond this would be aggregated as part of overflow attribute.