ActiveRecord find_each combined with limit and order

Question

I\'m trying to run a query of about 50,000 records using ActiveRecord\'s find_each method, but it seems to be ignoring my other parameters like so:

Answer 1

I had the same problem with a query with DISTINCT ON where you need an ORDER BY with that field, so this is my approach with Postgres:

def filtered_model_ids
  Model.joins(:father_model)
       .select('DISTINCT ON (model.field) model.id')
       .order(:field)
       .map(&:id)
end

def processor
  filtered_model_ids.each_slice(BATCH_SIZE).lazy.each do |batch|
    Model.find(batch).each do |record|
      # Code
    end
  end
end