[saxenaabhi]

I mean a bank account sending money to another bank account. That would be 2 events(one withdraw and one deposit)?

But if I'm downstream consumer consuming the event log and computing the state from that, if for some reasons I receives only first event the state computed would be invalid and not represent the real state of accounts?

[manoDev]

Nobody relies on atomic transactions to model money transfers in the real world. You can read up on "clearing" and "settlement" processes to get an idea.

[herval]

It could be one event with two database rows inserted, CQRS doesn’t have to map 1:1 to db entries. But in general, these kinds of systems are more complex than 1 or 2 writes, so relying purely on transactions isn’t very common