1. A method stored in one or more data-storage devices and executed using one or more processors of a computing environment, the method comprising: receiving a query at a master node about use of computational resources of the computing environment; distributing metric data generated by data sources in the computing environment to one or more worker nodes, the metric data represents use of the computational resources; each worker node performs the following: receiving the query from the master node, generating worker-node data that represents the metric data received by the worker node in response to the query, and sending the worker-node data to the master node; and calculating at the master node a master-data structure that represents a distribution of the metric data over data-structure intervals based on the worker-node data sent from the worker nodes.