Systems and methods execute a computer program to produce a trace of the computer program and divide the trace into independent threads of execution. Each of the independent threads of execution comprises an execution sequence of the lines of programming code that ends with an identified write line of programming code that outputs an incorrect result. These systems and methods also identify key field within each of the independent threads of execution. In programming, which is processing records in a table one by one, key-fields are a subset of the fields of the table. The key fields impact the computations sequence leading up to the identified write line of the programming code. These systems and methods identify key-based dynamic slices from the independent threads of execution. Each of the key-based dynamic slices includes lines of programming code that are used in computations, processing the table records corresponding to the key fields.