We have two schemas: Batch and Feed. They have a many to many relationship between them. When creating a Batch it will often be associated with thousands of feeds. We’re using this code to create the Batch and associate it with existing feeds: feeds = Feed |> where([f], f.feed_id in ^feed_ids) |> R…

In situations like this I try to use a transaction with Ecto.Multi.new. Once the transaction is created, the first step would be to insert the parent record, and the second step would be to create the child records using Repo.insert_all. This makes the transaction really fast, since there would be …