1. A computer program product, the computer program product being tangibly embodied on a non-transitory computer-readable storage medium and comprising instructions that, when executed, are configured to cause at least one computing device to: receive a stream of queries to be applied against data in a columnar-store database in which hot data is stored in an in-memory database for preferred access relative to warm data stored in a disk-based database; track usage counts for columns of the columnar-store database, reflecting usage thereof by individual queries of the stream of queries; select column sets, each column set including at least one column of the columnar-store database; calculate, for each column set, at least one record count of data records that include a column value, and at least one distinct count of distinct column values within each column set; generate at least one dynamic data unit from the column sets, based on the usage counts, the at least one record count, and the at least one distinct count, the at least one dynamic data unit including a set of data records sharing at least one common column value; analyze partitions of the data, based on the at least one dynamic data unit, to thereby obtain updated partitions; identify updated hot data and updated warm data within the updated partitions, based on the at least one dynamic data unit; and execute a data swap of data units from the partitions to the updated partitions, using the at least one dynamic data unit, to thereby have the updated hot data positioned within the in-memory database and the updated warm data within the disk-based database.