Right. But that's at the end of a separate article, while the post which this HN discussion is about throws around the words "exactly once" a lot more casually.

Right. But that's at the end of a separate article, while the post which this HN discussion is about throws around the words "exactly once" a lot more casually. The argument is over the use of the words "exactly once". They should just refer to the feature as "transactions" or "idempotent producer".