A system for sampling raw data from a reporting application and segmenting portions of the sampled data into at least one of a set of raw data stores. The system enables ad hoc querying to be done against a data warehouse using the set of raw data stores and in conjunction with an aggregate store. A reporting aspect of the system is responsible for locating the appropriate store when responding to a query. The system also segments data based on anticipated usage of the raw data and appropriately places them into a raw data store having an access speed that corresponds to the anticipated usage level of the data.