alt Hacker NewsActiveRecord may be both the best and worst part of Rails. Currently the largest scaling problem that I'm facing is with all the before_* and after_* callbacks which run per model record rather than a batch of changed records. This is an N+1 query landmine field for which ActiveRecord offers no solutions.
I agree that ActiveRecord isn't particularly opinionated about how to deal with updates to batches of records, but there are multiple ways of approaching this and AR won't get in your way.
upsert_all[1] is available to update a batch of records in a single write that does not invoke model callbacks.
activerecord-import[2] is also very nice gem that provides a great api for working with batches of records.
It can be as simple as extracting your callback logic and a method (def self.batch_update) and running your callback logic after the upsert.
[1] https://api.rubyonrails.org/classes/ActiveRecord/Relation.ht... [2] https://github.com/zdennis/activerecord-import