A stream of tuples is received to be processed by processing elements operating on one or more computer processors with each processing element having one or more stream operators. A breakpoint is identified for a stream operator that is configured to be triggered when time for processing of a tuple by the first stream operator is predicted to exceed a threshold time. A tuple is received at the stream operator having a set of attributes. A predicted time to process the tuple is determined based on the set of attributes. It is determined that the predicted time exceeds the threshold time. The breakpoint is triggered, in response to determining that the predicted time exceeds the threshold time, to pause processing of the tuple by the first stream operator.