[hot_gril]

Never heard of durable execution until now, but I've wondered about it. When I write backend code, I have to keep asking myself "what happens if the server goes down during this line of code?" This is often an issue in the middle of a customer order, like the example here. I end up relying on the database for very many tiny little things, like recording the fact that the user initiated an order before I start to process it.

But how fast is this? IIRC each little insert in my DB was taking like 5ms, which would add up quickly if I were to spam it everywhere; I assume durable execution layers are better optimized for that. Do they really only snapshot before and after async JS calls, treating all other lines as hermetic and thus able to be rerun?

[lorendsr]

Yeah, I’ve also written this write-to-db-after-each-meaningful-line-of-code style code, and this is a great improvement. See the first 20m of this talk for an example: https://youtu.be/EFIF8gk9zy8

Starting a workflow is currently ~40ms, and I think we’ll be able to get down to 10ms this year. How long it takes to complete depends on how many persisted steps it takes (and whether it has to wait on an external event). The only steps that are persisted are workflow api calls like sleep(), startChildWorkflow(), or calling code that might fail (ie “Activity”, like a network request).

[hot_gril]

> The only steps that are persisted are workflow api calls like sleep(), startChildWorkflow(), or calling code that might fail (ie “Activity”, like a network request).

Ok, that's what I was wondering. Makes a lot more sense this way.