Rails postgresql how to set transaction isolation level to serializable

Question

I have a Comment model which belongs_to a Topic model. On the Comment model, I have a before_create callback

def on_create
  Topic.transaction(:require_new =         


        

Answer 1

As of Rails 4, #transaction provides an :isolation option:

If your database supports setting the isolation level for a transaction, you can set it like so:

Post.transaction(isolation: :serializable) do
  # ...
end