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By the way, am I right in assuming that Adaptive Indexing must have been way more straightforward to implement for Datomic than for ordinary databases, due to writes being separated from reads?


Hi! I´m getting this error when connecting to Datomic Cloud from Lambda: Unable to connect to system: {:cognitect.anomalies/category :cognitect.anomalies/unavailable, :cognitect.anomalies/message “Connect Timeout”}: clojure.lang.ExceptionInfo clojure.lang.ExceptionInfo: Unable to connect to system: {:cognitect.anomalies/category :cognitect.anomalies/unavailable, :cognitect.anomalies/message “Connect Timeout”} {:config {:server-type :cloud, :region “us-west-2”, :system “datomic-cloud-prod”, :query-group “datomic-cloud-prod”, :endpoint ““, :endpoint-map {:headers {“host” “}, :scheme “http”, :server-name “”, :server-port 8182}}} at clojure.core$ex_info.invokeStatic(core.clj:4754) at clojure.core$ex_info.invoke(core.clj:4754) at$get_s3_auth_path.invokeStatic(cloud.clj:171) at$get_s3_auth_path.invoke(cloud.clj:162) at$create_client.invokeStatic(cloud.clj:205) I read past responses on having your S3 IAM policies squared away. I think I have everything setup (indeed, it worked before, not sure what we did :s). I’d appreciate any help!


Funny thing is that it stopped working at some point. I will try creating a VPC endpoint. Will report back.


Curious to know what kind of success you find. The VPC endpoint solution is much simpler than my original private subnet suggestion, but I have yet to try it myself.


Hi! I’m trying to get Peer Library of Datomic Pro, using Leiningen, but I cannot find it in Clojars. I had already com.datomic/datomic-free "0.9.5206" version working but it seems there is no version for “pro” one hosted there I think. Do you know I place to get the latest version from Leiningen?


you need an account from than you can use a special Datomic repository with credentials. It should be documented.

Alex Miller (Clojure team)17:05:26

if you look at portal with your login, there are instructions.


Perfect, thanks!


Been running into this error all day trying to use Datomic Cloud. It's being thrown while trying to call d/client. Has anyone encountered this before? >NoClassDefFoundError Could not initialize class com.amazonaws.partitions.PartitionsLoader com.amazonaws.regions.RegionMetadataFactory.create (


This is with version 0.8.52 of com.datomic/client-cloud


Ah, never mind. I had to add this line to my project.clj:

[ring-webjars "0.2.0" :exclusions [com.fasterxml.jackson.core/jackson-databind]]
Dependency hell strikes again


Hi! I’m looking for some guidance on storing time values in datomic (on-prem). I’ve been developing my app using the new java.time classes (via and I’m running into issues trying to coerce values into datomic friendly values.


Specifically, coercing OffsetDateTime into Instant that is compatible with :db.type/inst


The application is for scheduling appointments/resources


I have essentially resigned myself to using java.util.Date instances as values, and to only use the new java.time classes when doing arithmetic


Kind of a beginner question... As a datomic peer, if I query against the result of (datomic.api/db connection), am I querying against database as it appeared at the point in time when that function was called, or am I querying against the database in real-time? The reason I'm asking is because it sounds to me like the documentation is implying the former, and that sounds magical, so I want to make sure

Retrieves a value of the database for reading. Does not
communicate with the transactor, nor block.


@bj it is the former. Datomic is kind of like a git repo, where "db" is a commit hash, and "conn" is a branch name.


You don't get a whole snapshot of the database in memory. Pieces are loaded as required. But it is a coherent point-in-time snapshot.


Thanks, and I like that analogy


@donaldball are you converting to java.time classes in queries?


That is, in :where clauses?