@stuartrexking I would make schema transactions part of your deployment process, not part of the app bootup

Especially when there are several nodes waking up to do the same work concurrently

You could certainly use conformity as a library or script

I just mean: do it in a separate moment from app bootup.

@ghadi Is that necessary if planning for accretion and adhering to the schema growth principle? https://docs.datomic.com/cloud/best.html#plan-for-accretion

I just don’t see the benefit of doing it out of band of an app startup.

So what you are suggesting is, specific to ion app: 1. Push and deploy 2. Trigger a schema transaction (always or only when the schema has changed?)

Really what I want to know is why “I just mean: do it in a separate moment from app bootup.”

(The accretion principle still applies) If you have N nodes booting up, you have N racey processes trying to do the same work.

What I’ve seen work well is: Run tests, get a green check Transact new schema to DB Then deploy The app can presume that its schema exists in the DB - or exit if it doesn’t

The Ion sample uses an endpoint to trigger schema installation, but in a real app you’d likely have code that expects the schema to be there, along with the schema installation code, so it’s a catch 22

Thanks seems like a good approach. I’ll do that.

Well, I transact the schema on bootup, as there are only 4-6 nodes of that particular service, no issues so far

• Wanna play with Datomic Pro Starter Edition. Does the “Running more than 3 processes (2 peers + transactor)” not allowed still apply?