I think a clearer way to think about this is "at least once" message delivery plus idempotent workflow execution is effectively exactly-once event processing.

The DBOS workflow execution itself is idempotent (assume each step is idempotent). When DBOS starts a workflow, the "start" (workflow inputs) is durably logged first. If the app crashes, on restart, DBOS reloads from Postgres and resumes from the last completed step. Steps are checkpointed so they don't re-run once recorded.

The specific claim is that workflows are started exactly-once in response to an event. This is possible because starting a workflow is a database transaction, so we can guarantee that exactly one workflow is started per (for example) Kafka message.

For step processing, what you say is true--steps are restarted if they crash mid-execution, so they should be idempotent.

I'm from Pontevedra. It has been the major's long-term project (~ 20 years) to make the city for the pedestrians: and he's done it. This works mainly because of two things: 1) the city is small and it takes aprox 30 min to walk it entirely from end to end, and 2) it is mostly flat. Only a smooth hill from "orillamar" to "alameda/peregrina". Unfortunately, the major obsessed with getting rid of cars (which I am highly grateful) but forgot to provide reliable public transport to close-by villages (max 5km,i.e., Poio/Marin/Salcedo). This means tha people from these villages commute by car to the city, which has really poor parking capacity. And the most important thing: there are zero specialized jobs in Pontevedra. Either you are a public state worker, for which you need to pass an exam to lock a lifelong job with no possibility of being fired regardless of how incompetent you are, or you work in hospitality. My partner works in Santiago and I work in the UK. There is no future for us in our city unless we want to study and compete for a position with thousands of other Spaniards. I firmly believe the major should also prioritise quality jobs. It is pretty nice for tourists to experience a city with no cars, but the reality of most locals is that they either leave or settle to accept precarious jobs.

I don't really like your snarky initial take, even when I'm the guy calling bullshit in the first place in the thread.

People propagate falsehoods for numerous reasons. The first is, they don't know it's false. They hear a joke or a hypothetical story and repeat it as fact, and in the retelling it gets amplified. Details get conflated; someone hears a story about slightly radioactive cows and also about computers being affected by radiation, and blends them. Or an expat tells a story about his homeland, exaggerated slightly for effect, and is misunderstood by those who hear it based on their own biases.

In the end we only have so much brainpower. We don't always consider the plausibility of everything to a deep degree. I am nearly positive that you have propagated falsehood where you "should have known better."

And sometimes we tell things that are just a good story. I propagate the neural network tank recognition one to my students because it's a perfect story. I do say that I know it's probably false, but I'm sure some of them will repeat it to others as fact.

Calm down Igor, it's probably just a tall tale the seniors told the juniors and the juniors took it in as the truth.

Also didn't you have sarcastic Chornobyl jokes in the 80s if you lived anywhere near East or Central Europe? We certainly did have a lot of them in East Germany.

Bullshit. There is no way that living things are releasing enough ionizing radiation to interfere with a computer, especially an older one--

attenuated both by the rest of their flesh, the building's walls, the computer's chassis, and at least several feet of free space/inverse square.