Rake task which consumes many data freezes

Question

Hi all,

I have a simple rake task which consumes pretty much data via ActiveRecord. (contacts has ~47k rows)

Contact.all.each do |contact|
  contact.update_attribute ...
end

When I run that task ~400 rows get updated and then the task stucks. No errors and no database activity at all...

How do I make this work properly?

Answer 1

This is exactly what find_in_batches is intended for. It will eliminate an enormous number of ActiveRecord objects in memory at once.

http://ryandaigle.com/articles/2009/2/23/what-s-new-in-edge-rails-batched-find