I was trying to think of a use case for this and I was reminded of a Sun Microsystems demo (yes I'm that old) I saw. The paused a JVM and "slept" it, then kicked up on another machine almost instantly, all over the network. Was a pretty cool party trick, but then they did it when an HTTP request came in (Serverless was invented a LONG time ago!). I kinda wonder if this could be used for that?

what is your input on these two topics? aka pull vs push and working well with serverless workflows

I've been reading the DBOS Java documentation and have some questions, if you don't mind:

- Versioning; from the looks of it, it's either automatically derived from the source code (presumably bytecode?), or explicitly set for the entire application? This would be too coarse. I don't see auto-configuration working, as a small bug fix would invalidate the version. (Could be less of a problem if you're looking only at method signatures... perhaps add to the documentation?) Similarly, for the explicit setting, a change to the version number would invalidate all existing workflows, which would be cumbersome.

Have you considered relying on serialVersionUID? Or at least allowing explicit configuration on a per workflow basis? Or a fallback method to be invoked if the class signatures change in a backward incompatible way?

Overall, it looks like DBOS is fairly easy to pick up, but having a good story for workflow evolution is going to be essential for adoption. For example, if I have long-running workflows... do I have to keep the old code running until all old instances complete? Is that the idea?

- Transactional use; would it be possible to create a new workflow instance transactionally? If I am using the same database for DBOS and my application, I'd expect my app to do some work and create some jobs for later, reusing my transaction. Similarly, maybe when the jobs are running, I'd perhaps want to use the same transaction? As in, the work is done and then DBOS commits?

I know using the same transaction for both purposes could be tricky. I have, in fact, in the past, used two for job handling. Some guidance in the documentation would be very useful to have.

Thank you.

one of the rough edges i've noticed w/DBOS is for workflows that span multiple services. all of the examples are contained in a single application and thus use a single dbos 'system db' instance. if you have multiple services (as you often do in the real world) that need to participate in a workflow.. you really can't. you need to break them into multiple workflows and enqueue them in each service by creating an instance of the dbos client pointed at the other services system db. aside from the obvious overhead from fragmenting a workflow into multiple (and that you have to push to the service instead of a worker pulling the step), that means that every service needs to be aware of and have access to, every other services system db. also worth noting that sharing a single system db between services was not advised when i asked.

(docs for the above: https://docs.dbos.dev/architecture#using-dbos-in-a-distribut...)

[0] https://useworkflow.dev/docs/deploying/world/postgres-world

But dbos doesn't have opensource release of web ui, which is most critical part for a workflow management tool.

Since competitor have all of itself opensource I don't think dbos will have a chance.