As mentioned in the definition of the non-transactional topology, Trident processes tuples in a batch, but this doesn't define what's in each batch. In the case of a transactional topology, a transactional spout guarantees what's in each batch. A transactional spout has the following characteristics:
txid). In the case of failure, the entire batch is replayed. Hence, replays of the failed batch will contain the same set of tuples as the first time the batch was emitted. The
txidtransactional ID of the failed batch remains the same as the first time.