that's a very fair point. There are few applications where if the DB goes down, there's any point for the rest of the system to stay up. My use case happens to be distribution of financial tick info without persistence - ie: no cares on temporary data losses. Therefore it's very peer-oriented and doesn't care about lost messages or duplicated messages. All it cares about is throughput of latest data samples (note the world "samples". Not every single data point is needed though it's nice to have 99.999.. and we usually get that).

It's amazing how small use case differences can mean very big differences in the effectiveness of various strategies. The at least once / at most once / no guarantee either way but soft real time, use cases, can mean radically different toolchains. This is the real lesson of distributed streaming.