Term Kind Topic What it is
Fan-out on Write vs Fan-out on Read Push vs Pull Timelines concept Messaging & Queues Whether an event is copied to every recipient's store at publish time, or assembled from sources at read time - and why large systems need both.
Message Ordering concept Messaging & Queues The guarantee about the sequence in which messages are delivered — normally per-partition or per-group only, and lost the moment consumption is parallelised.