A cloud-based service records time-series data of a plurality of metrics from a plurality of tenants. The time-series data comprises a series of measures of a metric at sequential points in time. The time-series data is recorded in database tables in a manner that consumes more resources when the cardinality of the time-series data is high. When the cardinality of the data for the tenant is too high, the tenant is blacklisted and further data for the tenant is not stored. In addition to identifying incoming time-series data by the tenant that produced it, the data may also identify its type. In this case, the cardinality of each type of data may be determined and the types of data may be individually allowed or blacklisted for the tenant.