Resolution of Deadlocks in Object-Oriented Distributed Systems

The use of locks on objects to enforce correct scheduling of concurrent transactions gives rise to deadlock situations. We propose and prove correct a distributed algorithm for detection and resolutions of resource deadlocks in object-oriented distributed systems. In particular, the algorithm can be used in conjunction with concurrency control algorithms which are based on the semantic lock model. In order to drastically reduce message traffic, the algorithm properly identifies and eliminates redundant messages. We show that both its worst and average time complexities are O (n x e), where n is the number of nodes and e is the number of edges in the waits-for-graph. After deadlock resolution, the algorithm leaves information in the system concerning dependence relations of currently running transactions. This information will preclude the wasteful retrans-mission of messages and reduce the delay in detecting future deadlocks.