Rails иногда зависает после HTML POST - чрезвычайно долгое время активной записи

Question

У меня есть приложение Rails 4, которое иногда зависает на 5 минут за раз, оставляя сайт недоступным для всех.Иногда, когда запускается HTTP POST, исходящий из / plays, сервер полностью блокируется и перестает отвечать на запросы.

Согласно этому источнику ниже, ActiveRecord следует использовать экономно, а также сокращать использование .all с find_in_batches

https://chaione.com/blog/dealing-massive-data-rails/ActiveRecord

Мое подозрение было в том, что set_plays в PlaysController, возможно, был виновником, но теперь я больше склоняюсь к неправильному использованию функции кэша рельсов, так как эта проблема возникает с нерегулярными интервалами и являетсятрудно воспроизвести.

Ниже приведен фрагмент от контроллера воспроизведения.

class PlaysController < ApplicationController
  helper PlaysHelper
  load_and_authorize_resource
  before_action :set_plays, only: [:index, :create]
  before_action :set_play, only: [:show, :edit, :update, :destroy]
  respond_to :html, :json

  layout "layouts/tabs"

  before_filter :title
  before_filter :set_links

  def new
    @play = Play.new
    respond_with(@play)
  end

  def create
    @play = Play.new(play_params)
    @play.show ||= @play.get_show(current_user)
    if pbn = params[:playbox_number]
      @play.playbox_number = pbn
    end
    if @play.save
      begin
        report_play_to_shoutcast(@play) if Rails.env.production?
      rescue StandardError => e
        flash[:error] = "Unable to report play to SHOUTcast #{e.inspect}\n#{e.backtrace[0]}"
      end
      begin
        report_play_to_tunein(@play) if Rails.env.production?
      rescue StandardError => e
        flash[:error] = "Unable to report play to tunein #{e.inspect}\n#{e.backtrace[0]}"
      end
      # clear the cache of anything with play information in it
      clear_plays_cache
      # go ahead and reset the last_play cache, because we already have the value in hand
      set_last_play(@play)
      @play = Play.new
      render(action: :index)
    else
      respond_with(@play)
    end
  end

  private
    def set_play
      @play = Play.find(params[:id])
    end

    def set_plays
      @plays = Play.all.paginate(page: params[:page], per_page: 50, total_entries: plays_count() ).order('created_at DESC').preload(:show,:playbox)
    end

    def play_params
      params.require(:play).permit(:artist, :album, :track, :show_id)
    end
end

И часть помощника приложения

module ApplicationHelper

  def set_last_play(play)
    Rails.cache.write("plays__last_play", play, expires_in: 5.minutes, race_condition_ttl: 10.seconds)
  end # set_last_play

  def last_play
    @last_play ||= Rails.cache.fetch("plays__last_play", expires_in: 5.minutes, race_condition_ttl: 10.seconds) do
        Play.order("created_at").includes(:show).last || Play.new(album: "", artist: "", track: "", show: nil)
    end
  end # last_play

  def plays_count
    # only one 1 underscore (_) in order to avoid being eliminated by clear_plays_cache
    @plays_count ||= Rails.cache.fetch("plays_count", expires_in: 5.hours, race_condition_ttl: 10.seconds) do
        Play.count
    end
  end

  def clear_plays_cache
    Rails.cache.delete_matched('plays__')
  end # clear_plays_cache
end

Вот примервыдача из лог-файла

I, [2019-06-19T08:25:37.659021 #5772]  INFO -- : Started POST "/plays" for 127.0.0.1 at 2019-06-19 08:25:37 -0400
I, [2019-06-19T08:25:37.659021 #5772]  INFO -- : Processing by PlaysController#create as HTML
I, [2019-06-19T08:25:37.659021 #5772]  INFO -- :   Parameters: {"utf8"=>"✓", "authenticity_token"=>"REDACTED", "playbox_number"=>"", "play"=>{"artist"=>"Band", "track"=>"Song", "album"=>"Single", "show_id"=>"720"}, "commit"=>"Create Play"}
I, [2019-06-19T08:26:07.209014 #5772]  INFO -- :   Rendered plays/_playbox_requirements.html.erb (15.7ms)
I, [2019-06-19T08:26:07.209014 #5772]  INFO -- :   Rendered plays/_form.html.erb (15.7ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered plays/_table.html.erb (46.9ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered plays/index.html.erb within layouts/tabs (62.5ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered plays/_lastwidget.html.erb (0.0ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered application/_login.overlay.html.erb (0.0ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered layouts/application.html.erb (0.0ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered layouts/bootstrap.html.erb (0.0ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- :   Rendered layouts/bootstrap-wide.html.erb (0.0ms)
I, [2019-06-19T08:26:07.255871 #5772]  INFO -- : Completed 200 OK in 276754ms (Views: 66.8ms | ActiveRecord: 35996.5ms)