A computer-implemented method for tracking record level lineage of data records (330, 332) as they are processed by a dataflow graph, the method including: modifying a dataflow graph (102, 700), the dataflow graph (102, 700) including components and links, wherein the components include a data source (214, 702), a data sink and processing components (308, 406, 512, 704, 802, 808, 810, 904), and wherein links identify flows of data records among the components, and wherein the dataflow graph including a plurality of paths (108, 110) connecting at least one entry point into the dataflow graph (102, 700) and at least one exit point from the dataflow graph (102, 700), wherein the data source (214, 702) provides the entry point and reads data records (330, 332) to be processed by the dataflow graph (102, 700), and wherein the data sink provides the exit point and stores output data records (330, 332) from the dataflow graph (102, 700) once the dataflow graph (102, 700) has completed processing, including: adding processing components (308, 406, 512, 704, 802, 808, 810, 904) to the dataflow graph (102, 700) that add flow units (304, 306, 310, 312) to data records (330, 332) processed by the added processing components (308, 406, 512, 704, 802, 808, 810, 904) and remove flow units (304, 306, 310, 312) from data records processed by the added processing components (308, 406, 512, 704, 802, 808, 810, 904), each flow unit (304, 306, 310, 312) being an additional field added to a data record (330, 332) and identifying a segment of an execution path traversed by the data record (330, 332), the execution path being one of the plurality of paths (108, 110),, and preceding data records used to produce the data record; processing, by a dataflow graph run-time environment hosted on one or more computers, the data records (330, 332) using the modified dataflow graph; identifying, from the plurality of paths (108, 110), execution paths based on the flow units (304, 306, 310, 312) obtained by the processing of the data records using the modified dataflow graph; determining a subset of the data records (330, 332) having traversed a selected set of the execution paths, so that flow coverage of the subset of the data records (330, 332) through the dataflow graph remains consistent when compared to flow coverage produced by the modified dataflow graph when processing the complete set of data records (330, 332) from the data source (214, 702). modifying a dataflow graph (102, 700), the dataflow graph (102, 700) including components and links, wherein the components include a data source (214, 702), a data sink and processing components (308, 406, 512, 704, 802, 808, 810, 904), and wherein links identify flows of data records among the components, and wherein the dataflow graph including a plurality of paths (108, 110) connecting at least one entry point into the dataflow graph (102, 700) and at least one exit point from the dataflow graph (102, 700), wherein the data source (214, 702) provides the entry point and reads data records (330, 332) to be processed by the dataflow graph (102, 700), and wherein the data sink provides the exit point and stores output data records (330, 332) from the dataflow graph (102, 700) once the dataflow graph (102, 700) has completed processing, including: adding processing components (308, 406, 512, 704, 802, 808, 810, 904) to the dataflow graph (102, 700) that add flow units (304, 306, 310, 312) to data records (330, 332) processed by the added processing components (308, 406, 512, 704, 802, 808, 810, 904) and remove flow units (304, 306, 310, 312) from data records processed by the added processing components (308, 406, 512, 704, 802, 808, 810, 904), each flow unit (304, 306, 310, 312) being an additional field added to a data record (330, 332) and identifying a segment of an execution path traversed by the data record (330, 332), the execution path being one of the plurality of paths (108, 110),, and preceding data records used to produce the data record; processing, by a dataflow graph run-time environment hosted on one or more computers, the data records (330, 332) using the modified dataflow graph; identifying, from the plurality of paths (108, 110), execution paths based on the flow units (304, 306, 310, 312) obtained by the processing of the data records using the modified dataflow graph; determining a subset of the data records (330, 332) having traversed a selected set of the execution paths, so that flow coverage of the subset of the data records (330, 332) through the dataflow graph remains consistent when compared to flow coverage produced by the modified dataflow graph when processing the complete set of data records (330, 332) from the data source (214, 702).