A computing resource monitoring service receives a request to retrieve measurement data for a metric. The computing resource monitoring service determines, based at least in part on information included in the request, one or more in-memory datastores where the measurement data is stored. If the information indicates that the computing resource monitoring service is to provide an authoritative subset of the measurement data, the computing resource monitoring service limits the data provided in response to the request to the authoritative subset of the measurement data. Otherwise, if the information does not specify this indication, the computing resource monitoring service will provide the measurement data that is available.