Debugging in a Distributed World: Observation and Control

Debugging distributed programs is considerably more difficult than debugging sequential programs. We address issues in debugging distributed programs and provide a general framework for observing and controlling a dis-tributed computation and its applications to distributed de-bugging. Observing distributed computations involves solv-ing the predicate detection problem. We present the main ideas involved in developing efficient algorithms for pred-icate detection. Controlling distributed computations in-volves solving the predicate control problem. Predicate control may be used to restrict the behavior of the dis-tributed program to suspicious executions. We also present an example of how predicate detection and predicate con-trol can be used in practice to facilitate distributed debug-ging. 1