flauta | Waveguide based flute model | Audio Utils library

You're trying to do too much within a single http request/response cycle. For every row in your CSV you're doing a sql INSERT (with dbUser.recipes.create), an UPDATE (with dbRecipe.save), as well as a SELECT (with Food.find_by_name(food)).

Even if you make some optimizations, are you sure that the CSV will only have ~300 rows for the life of your app? And even if the answer is yes, generally speaking it is good practice to respond to a user action as quickly as possible instead of having them watch their browser wait for a response.

So, I recommend you rethink your approach. If a single action has to execute a lot of sql commands, think of ways to have the task run asynchronously. This is what tools like ActiveJob (https://edgeguides.rubyonrails.org/active_job_basics.html) and sidekiq (https://github.com/mperham/sidekiq/) were designed for.

For example, design your app in such a way that a user clicks some button for uploading the CSV and respond with: "Thanks for your submission, we're working on it!". The user could always come back and check the status of the file being processed or refresh the screen. Or you could get more sophisticated and automate status checks with AJAX polling or bi-directional communication via websockets. The Railsy way to do this would be with ActionCable (https://guides.rubyonrails.org/action_cable_overview.html).