Exactly. What Calvin (and FaunaDB, I think) does is allow you to run an arbitrary function which takes input on the database. That function can do whatever it wants, including any number of reads, writes, and arbitrary logic based on the reads. But critically, it can't talk back to the calling client, except for to send the final result.
This allows you to implement the pattern you describe, which I agree is common, but in a dramatically simpler way.
Having the database, which is not really a single thing, but a swarm of computers spread across the globe separated by unreliable links who are trying to stay in consensus, pause their work to hear back from the client just seems ... well it seems miraculous that it can work at all.
The Calvin way is so much easier, it seems like there must be some very good reason that it's not what CockroachDB does. But I've never heard what that reason is.
This allows you to implement the pattern you describe, which I agree is common, but in a dramatically simpler way.
Having the database, which is not really a single thing, but a swarm of computers spread across the globe separated by unreliable links who are trying to stay in consensus, pause their work to hear back from the client just seems ... well it seems miraculous that it can work at all.
The Calvin way is so much easier, it seems like there must be some very good reason that it's not what CockroachDB does. But I've never heard what that reason is.