1. A method of managing execution of query operations in a data processing system, comprising: issuing, by a requesting entity, a request to perform a composite query operation defined by at least an initial query operation and a plurality of subsequent query operations to be executed against a data repository of the data processing system; executing the initial query operation; determining an operation status of the initial query operation; selecting one of the plurality of subsequent query operations based on the operation status; performing the selected subsequent query operation; updating the operation status based on a result of the subsequent query operation; managing execution of any remaining subsequent query operations on the basis of the updated operation status; and upon determining the composite query operation has completed, returning a result of the composite query operation to the requesting entity.