29. The system of claim 28 wherein root cause estimator identifies root cause candidates by calculating a cumulative impact factor for each event in the event graph on all of the other events in the event graph; ranking events according to the cumulative impact factor; and selecting a subset of events in the event graph having highest cumulative impact factor as root cause candidates.
28. The system of claim 20 further comprises a root cause estimator that identifies root cause candidates for a performance problem in the distributed computing environment, where the root cause candidates are identified from the plurality of event records and a plurality of event causality records forming an event graph in the repository.