Resolution of Parallel Deadlock by Partial Abortion

A distributed system is composed of multiple objects intercon-nected data type. Users write transactions to manipulate distributed objects in a nested fashion. Transactions are composed of operations and also atomic units of work for users. Each operation can call operations on another objects. Suppose that one operation op1 on an object o1 calls two operations op2 on p and op3 on q. op2 and op3 can be called in parallel. This means that op1 can be executed in parallel. In this sense, nest-ed transactions can be executed in parallel in the distributed systems. In this paper, we would like to discuss deadlock problems occurred when transactions are executed in parallel. 1