Dynamic replacement of degrading processing elements in streaming applications

A computer implemented method is provided. The method includes monitoring a distributed computing application at runtime for occurrence of a condition, where the condition includes occurrence of a degradation condition on a processing element (PE). The method also includes starting a provisional PE on a second node at runtime while maintaining runtime operation of the PE. The method compares operation of the PE to operation of the provisional PE based on a performance metric associated with the computing resource. The method connects the provisional PE to replace the stream of tuples from the PE to a downstream PE with a stream of tuples from the provisional PE to the downstream PE.