Hi. I'm trying to find some datomic benchmarks (on real cases). I am wondering how fast I can write msg into datomic (writes / s). I can only find "it is not so fast at writing", "writing is not the strongest point of datomic"...cool but this is closer to 10 writes / s or 10000 writes /s compared to other databases?

Rule of thumb is keep database size smaller than 10 billion datoms, which if you reach that in a year is 317 datoms per second. At that rate you are very likely to be read constrained, not write constrained

“datomic is not fast at writing” lacks sufficient nuance to be useful at all

If you transact 10k datoms per second, you’ll have 10 billion datoms in 10 days

Wow. Thank you. Now I see.

@m_m_m You’re not finding the results because of a few different reasons: 1. Its against the license 2. writing of different sizes, shapes, constraints, batches of data will yield different results. 3. It’s harder to compare to other systems due to query groups allowing for reads to come for free and letting your primary groups focus exclusively on writes. My understanding with datomic cloud is that if you run into a write performance constraint you can crank up the knob on dynamodb’s write throughput and use an i3.xlarge as your primary group. When to do that and what it will produce I can’t answer, as I haven’t had to do that. Can I ask what the usecase is?

@joe.lane Sure, I would like to store items form multiple games. Those items have content and state which can be changed in time (the same with owner). Datomic can give me whole history of each of those items which is nice....but more important feature is easy access to the newest state of each of those items. Hmm is there a huge difference between performance of proverion and free version of datomic?

Well Free version of datomic is, I believe, in memory and on-prem. I was referring to datomic cloud.

How about performance of the "on-perm" version?

My 1 and 2 are still relevant, but 3 falls off and so does the i3.xlarge/knob-cranking. I don’t have the experience with on-prem. Is the “access the whole history of each item” part of the game or just a development convenience?

development convenience. There should be possibility to see history of the item, price changes, owner changes, stats changes in time 🙂

Does anyone here have an on-prem Dockerfile, maybe with sqlite jdbc backend for CI from a known-good database?

@m_m_m you shouldn't rely on datomic's history features to model your domain, its really mostly just an audit thing, add your own time as needed

https://vvvvalvalval.github.io/posts/2017-07-08-Datomic-this-is-not-the-history-youre-looking-for.html

@lockdown- I'm a bit confused by the author's "revision entities" example

how does it route around the fact that the tags don't exist in the previous versions?

maybe I'm just not reading the queries correctly

(def con! (d/connect "datomic:))
Syntax error (ClassNotFoundException) compiling at (form-init3668295776313994723.clj:1:11).
com.amazonaws.services.dynamodbv2.model.PutItemRequest

guess i’m missing a dependency somewhere

(using a plain deps.edn with just datomic pro in there)

you probably need the dynamodb dependency from the AWS Java SDK, like this: https://docs.datomic.com/on-prem/storage.html#dynamodb-aws-peer-dependency

thanks gws, that was exactly it