Perhaps the only difference is that Azure Durable Functions has more syntactic sugar in C# (instead of DBOS choice being Python) to preserve call results in the persistent storage? Where else do they differ? At the end, all of them seem to be doing what Temporal is doing (which has its own shortcomings and it's also possible to get it wrong if you call a function directly instead of invoking it via an Activity etc)?
KraftyOne · 49s ago
Both do durable workflows with similar guarantees. The big difference is that DBOS is an open-source library you can add to your existing code and run anywhere, whereas Durable Functions is a cloud offering for orchestrating serverless functions on Azure.
cpursley · 31m ago
I've been using https://www.pgflow.dev for workflows which is built on pgmq and am really impressed so far. Most of the logic is in the database so I'm considering building an Elixir adapter DSL.
ishita_julep · 18m ago
what are you using the DSL for?
at0mic22 · 10m ago
Every few years someone discovers FOR UPDATE SKIP LOCKED and represents it. I remember it lasting for 15 years at least
abtinf · 11m ago
Why not just use Temporal?
tonyhb · 13m ago
Anything that guarantees exactly once is selling snake oil. Side effects happen inside any transaction, and only when it commits (checkpoints) are the side effects safe.
Want to send an email, but the app crashes before committing? Now you're at-least-once.
You can compress the window that causes at-least-once semantics, but it's always there. For this reason, this blog post oversells the capabilities of these types of systems as a whole. DBOS (and Inngest, see the disclaimer below) try to get as close to exactly once as possible, but the risk always exists, which is why you should always try to use idempotency in external API requests if they support it. Defense in layers.
Disclaimer: I built the original `step.run` APIs at https://www.inngest.com, which offers similar things on any platform... without being tied to DB transactions.
KraftyOne · 9m ago
As the post says, the exactly-once guarantee is ONLY for steps performing database operations. For those, you actually can get an exactly-once guarantee by running the database operations in the same Postgres transaction as your durable checkpoint. That's a pretty cool benefit of building workflows on Postgres! Of course, if there are side effects outside the database, those happen at-least-once.
tonyhb · 4m ago
You can totally leverage postgres transactions to give someone... postgres transactions!
I just figured that the exactly once semantics were so worth discussing that any external side effects (which is what orchestration is for) aren't included in that, which is a big caveat.
Perhaps the only difference is that Azure Durable Functions has more syntactic sugar in C# (instead of DBOS choice being Python) to preserve call results in the persistent storage? Where else do they differ? At the end, all of them seem to be doing what Temporal is doing (which has its own shortcomings and it's also possible to get it wrong if you call a function directly instead of invoking it via an Activity etc)?
Want to send an email, but the app crashes before committing? Now you're at-least-once.
You can compress the window that causes at-least-once semantics, but it's always there. For this reason, this blog post oversells the capabilities of these types of systems as a whole. DBOS (and Inngest, see the disclaimer below) try to get as close to exactly once as possible, but the risk always exists, which is why you should always try to use idempotency in external API requests if they support it. Defense in layers.
Disclaimer: I built the original `step.run` APIs at https://www.inngest.com, which offers similar things on any platform... without being tied to DB transactions.
I just figured that the exactly once semantics were so worth discussing that any external side effects (which is what orchestration is for) aren't included in that, which is a big caveat.