Method, system and computer program product for performing an operation, the operation including providing a plurality of processing elements comprising one or more operators, the operators configured to process streaming data tuples. The operation then establishes an operator graph of multiple operators, the operator graph defining at least one execution path in which a first operator of the plurality of operators is configured to receive data tuples from at least one upstream operator and transmit data tuples to at least one downstream operator. The operation then defines a breakpoint, the breakpoint comprising a condition, the condition based on attribute values of data tuples in a window of at least one operator, the window comprising a plurality of data tuples in an operator. The operation, upon detecting occurrence of the condition, triggers the breakpoint to halt processing by each of the plurality of operators in the operator graph.