@ghadi what's Prometheus?

I am not familiar

A superb monitoring system

https://prometheus.io/

@hendriklouw your query has O(n^2) complexity

you're scanning every (person, person) pair

try this instead

this one has O(n) complexity

nice, that works perfectly. Thank you @val_waeselynck

I have Datomic Pro, how does the 2 days support work?

who/what do I contact

https://support.cognitect.com/hc/en-us @erichmond

thanks!

could anyone possibly explain a use case for db.type/ref?

an attribute whose value references another entity

might make sense in the context of a cardinality many attribute, e.g. a person might have multiple addresses

okay... so the "value" of such a datom would be another entity?

the value is a reference to another entity

when you transact a value you can use the other entity ID directly, or a lookup ref (see http://blog.datomic.com/2014/02/datomic-lookup-refs.html)

like if I had a user and I had a project and I wanted to make a schema for the project owner, that would probably be a :db.type/ref with the user as the owner?

yep

gotcha, thank you!

np

okay let's say I have a bunch of schema {:db/ident user/attr ...} ... is it is possible to query all attributes that are available for user/*?

if you're getting all user/* attributes for a single entity use a pull query

ah okay

or if for multiple entities you can use pull-many

maybe I should be more clear I'm not looking for the attributes for any specific entity just all the attribute fields that relate to user

I mean I can clearly see them in the console but I'm wondering if there's a programmatic way to get them

an attribute can belong to any entity - it's not like a traditional relational table

you could probably do something with database functions in a datalog query, e.g. starts-with?

okay let me rephrase... is there a way to query over all the attributes and just get the ones that have :user as the beginning of their keyword?

ah I see

not something you'd typically need to do

agreed -- just feeling my way around

[:find [?attr-ident ...]
 :where
 [:db.part/db :db.install/attribute ?attr]
 [?attr :db/ident ?attr-ident]
 [(namespace ?attr-ident) ?attr-ns]
 [(= ?attr-ns "user")]]

@goomba note the namespace function

interesting... is the ... significant?

destructures so you get a list of items instead of a list of relations

http://docs.datomic.com/query.html#sec-5-8

okay, awesome 😄

now when I run this I'm getting Don't know how to create ISeq from: clojure.lang.Keyword ... could that just be because I haven't populated any data yet?

I'm looking up the docs I'm just trying to figure out which part of that query is supposed to be literal and which I'm supposed to fill in values for... e.g. in the :db.part/db am I supposed to put in the name of the db or is that a literal?

also @favila what are you up to like 5 beers that I owe you now? 😂

the query is all literal

has anyone seen this kind of error when trying to restore-db? java.util.concurrent.ExecutionException: java.util.concurrent.ExecutionException: com.amazonaws.AmazonClientException: Unable to execute HTTP request: <bucket>.