I load a CSV into two separate tables in my database and it works great. Now that I have moved the database to the cloud, it’s time to use batch inserts/updates, but all of the examples I find for Ecto.Multi are trivial examples and I’m not sure how to go about building a process that can ultimatel…

Hey @bodhilogic , Ecto.Multi is for executing multiple statements in a single transaction. It doesn’t batch inserts and updates. For that, you’d want to use insert_all or update_all defined on your repo. If all of your rows are inserted/updated in a single insert_all/update_all, you won’t need a tra…

Fantastic answer! Thank you so much :slight_smile:

To answer your question “how do I use Ecto.Multi in a loop”, you would use Enum.reduce/3 to build up the Multi as you process elements in an enumerable. def parse(_) do multi = Ecto.Multi.new() multi = File.stream!("uploads/#{file}", [:trim_bom]) |> CSV.decode(headers: true) |> En…

It can use SQL functions to set different values. Though, if you’re looking to pass data to update, insert_all + the upsert options on_conflict and conflict_target are probably what you want.

I will try with the insert_all function, thx. For maybe other people, reason I am asking is that I have a list of changesets, that I want to bulk update, not insert. Ecto.Multi is not suited, because it is for executing multiple statements in a single transaction. update_all/3 Is not suited becau…

[image] eddy147: Ecto.Multi is not suited, because it is for executing multiple statements in a single transaction. What is your problem with that exactly? That’s less DB concurrency and allows you to do more DB operations in parallel. When you say “X is too much DB I/O”, have you measured i…

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Ecto Multi in a Loop

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eddy147 March 8, 2022, 4:00am 5

isn’t update_all only used for updating multiple rows with the same value?