Centralized affinity maintenance in a workload managed client/server data processing system

In a client/server data processing system where a client sends a work request to a server which includes a group of workload managed server data processing processes each of which is capable of performing the work request, a server data processing apparatus running a server data processing process, the apparatus has: a data storage unit storing mapping data which maps a particular server data processing process to each of a plurality of groups of workload managed server data processing processes; a means for receiving from a client a request for the identity of the mapped server data processing process corresponding to a particular group of workload managed server data processing processes, the particular group being specified in the request; a means for accessing the data storage unit to determine, for the particular group specified in the received request, the identity of the mapped server data processing process; and a means for returning the identity of the mapped server data processing process to the client; wherein the request received from the client is associated with an entity whose lifetime is coupled to the lifetime of the server data processing process.