Automatic conversion of units of measure during data stream processing

Data streams are received for processing by a query. The query is associated with expected input data stream types and expected output data stream types. The received data streams are evaluated to determine if they correspond to the expected data stream types. If the received data stream types define data for a physical quantity that is defined in a unit of measure that is not the expected unit of measure, then unit conversion is required. Predefined mappings are utilized for performing required unit conversions and an optimal solution for conversion is determined. The unit conversions are performed automatically by unit conversion operators that are integrated within the process of generating of a runnable query. The runnable query is deployed and executed to generate result output streams that match the expected output stream type.