1. A method, in a data processing system, for data stream change detection and model swapping in a stream computing platform, the method comprising: building a model for each input data stream in a stream computing platform, wherein each tuple of each given input data stream is tagged with a key corresponding to the given input data stream; performing an operation on each input data stream using its corresponding model; detecting a misdirected input data stream, wherein the misdirected input data stream is tagged with a key that does not correspond to the misdirected input data stream; pausing the misdirected input data stream; and swapping a model corresponding to the misdirected input data stream with another model corresponding to another paused input data stream.