Client/server transaction data processing system with automatic distributed coordinator set up into a linear chain for use of linear commit optimization

A computing apparatus for use in a client/server transaction processing system, the apparatus has: a sending means for sending a transactional request to a server data processing apparatus to request that the server data processing apparatus become involved in processing a distributed transaction, the transactional request including an indication of a computing apparatus to which the server data processing apparatus should direct a registration request to request that a resource local to the server data processing apparatus be registered in the transaction; a receiving means for receiving a reply to the transactional request from the server data processing apparatus, the reply including an indication of an apparatus which is currently the last in a linear chain of apparatuses that have sent out registration requests in response to receiving transactional requests; and a keeping means for keeping track of the current apparatus which is the last in the linear chain based on replies received by the receiving means; wherein the indication sent to a server data processing apparatus by the sending means, along with the transactional request, is an indication of the current apparatus which is the last in the linear chain, based on the keeping means.