QuestionScheduler.rb

require 'benchmark'

class QuestionScheduler
  @queue = :email_notifications

  MAX_ATTEMPTS = 2

  # ============================================================
  # When both queries are constrained to :current_enrollments
  # the results are close with pluck ~2x speed improvement
  #                      user     system      total        real
  # pluck(:id)      65.550000   2.310000  67.860000 ( 69.107931)
  # select(:id)    119.030000   4.160000 123.190000 (129.350956)
  # ============================================================
  # When not constrained to :current_enrollments the results are
  # no longer in the same ballpark. See QuestionEmailer line:42
  # User.select(:id).find_each(batch_size: 1000)
  #                      user     system      total        real
  # select(:id)    809.560000   7.400000 816.960000 (817.421610)
  # ============================================================

  def self.enqueue_rollovers
    
    Benchmark.bm do |x|
      x.report('pluck uniq') do
        User.joins(:current_enrollments).uniq.pluck(:id).each do |id|
          Resque.enqueue(self, id)
        end
      end
      
      x.report("select id") do
        User.select(:id).find_each(batch_size: 1000) do |u|
          Resque.enqueue(self, u.id)
        end
      end
    end
    
  rescue => ex
    Airbrake.notify_or_raise ex
  end

  def self.perform(user_id)
    # do nothing for now
  end

end