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

Using Kaminari or something other it will be easy.

Create batch loader class.

module BatchLoader
  extend ActiveSupport::Concern

  def batch_by_page(options = {})
    options = init_batch_options!(options)

    next_page = 1

    loop do
      next_page = yield(next_page, options[:batch_size])

      break next_page if next_page.nil?
    end
  end

  private

  def default_batch_options
    {
      batch_size: 50
    }
  end

  def init_batch_options!(options)
    options ||= {}
    default_batch_options.merge!(options)
  end
end

Create Repository

class ThingRepository
  include BatchLoader

  # @param [Integer] per_page
  # @param [Proc] block
  def batch_changes(per_page=100, &block)
    relation = Thing.active.order("created_at DESC")

    batch_by_page do |next_page|
      query = relation.page(next_page).per(per_page)
      yield query if block_given?
      query.next_page
    end
  end
end

Use the repository

repo = ThingRepository.new
repo.batch_changes(5000).each do |g|
  g.each do |t|
    #...
  end
end