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- Operator Time: This usually gives the fastest results since using timestamps in processing might require waiting for slower operations and buffering of elements since the elements will arrive at operations out-of-order. That is, they are usually not ordered by their timestamps. This will, however, not give you any guarantees about the ordering of elements when joining several data streams and when operations require a repartitioning of the elements . since the timestamp of an element is essentially the time when it arrives at the operation.
- Event Time: This makes it possible to define orderings or time windows that are completely independent of the system time of the machines that a topology is running on. This might, however, lead to very high latencies because operations have to wait until they can be sure that they have seen all elements up to a certain timestamp.
- Ingress Time: This gives you a good compromise between event time and operator time. Even after repartitioning data or joining several data streams the elements can still be processed according to the time that they entered the system. The latency should also be low because the timestamps that sources attach to elements are steadily increasing.
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