Value dates for concurrency control and transaction management ininteroperable systems

摘要

Value dates appear, at present to be the most flexible concurrencycontrol paradigm for autonomous heterogeneous interoperable systems. Theprotocols are deadlock free, and can be livelock free in the situationwhen the two-phase locking protocol (2PL) creates a deadlock inpractice. Value dates accommodate the autonomy better. The commitprotocols possible with value dates can be also more efficient than thetwo-phase commitment protocol (2PC). The advantages of the value datesmake it worth the replacement of 2PL as the standard. Further researchshould concern the implementation issues. Another important issue is theuse of unsafe values. Applications often use unsafe values with valuedates for better efficiency, e.g. reservation systems