Why does Rails render the views so slowly? - ruby-on-rails

Question

Using Rails 4 and Ruby 1.9.3.
I have this view in usuarios#show I'm rendering. The controller demands a lot of data, but I have managed to reduce the queries with eager_load and akin from 300ms odd to a 44 ms.
My problem is that the database call is ok, but the views are taking close to 30 seconds to render.
I have made sure that I'm getting everything I use from the controller variables.
EDIT: I have added the query itself from the controller
This is the controller method, using eager_loading
#app/controllers/usuarios_controller.rb
before_action :show_usuario, only: [:show]
def show
if !#usuario.country_id.blank?
#country = #usuario.country
end
respond_to do |format
format.html
format.js
end
end
private
def show_usuario
if usuario_signed_in?
id = current_usuario.id
#usuario = Usuario.eager_load(:profile).find(id)
else
#usuario = Usuario.eager_load(:profile, textos: [:likes, :text_medals, :tags]).find(params[:id])
end
#textos = Texto.eager_load(:likes, :text_medals, :tags).where(:usuario_id => #usuario.id).order("textos.created_at DESC").paginate(:page => params[:page]).per_page(6)
end
Here is my log
Started GET "/" for 127.0.0.1 at 2014-03-25 12:55:39 +0100
Usuario Load (1.4ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = 12 ORDER BY "usuarios"."id" ASC LIMIT 1
Processing by UsuariosController#show as HTML
Notification Load (1.2ms) SELECT "notifications".* FROM "notifications" INNER JOIN "textos" ON "textos"."id" = "notifications"."text" WHERE (textos.usuario_id = 12 AND notifications.user_related != 12) ORDER BY "notifications"."id" DESC LIMIT 10
SQL (1.2ms) SELECT "usuarios"."id" AS t0_r0, "usuarios"."email" AS t0_r1, "usuarios"."encrypted_password" AS t0_r2, "usuarios"."reset_password_token" AS t0_r3, "usuarios"."reset_password_sent_at" AS t0_r4, "usuarios"."remember_created_at" AS t0_r5, "usuarios"."sign_in_count" AS t0_r6, "usuarios"."current_sign_in_at" AS t0_r7, "usuarios"."last_sign_in_at" AS t0_r8, "usuarios"."current_sign_in_ip" AS t0_r9, "usuarios"."last_sign_in_ip" AS t0_r10, "usuarios"."created_at" AS t0_r11, "usuarios"."updated_at" AS t0_r12, "usuarios"."nombre" AS t0_r13, "usuarios"."fecha_nac" AS t0_r14, "usuarios"."country_id" AS t0_r15, "usuarios"."is_admin" AS t0_r16, "usuarios"."publish_fbviews" AS t0_r17, "usuarios"."accept_terms" AS t0_r18, "profiles"."id" AS t1_r0, "profiles"."usuario_id" AS t1_r1, "profiles"."quote" AS t1_r2, "profiles"."quote_author" AS t1_r3, "profiles"."fb_account" AS t1_r4, "profiles"."twt_account" AS t1_r5, "profiles"."gpls_account" AS t1_r6, "profiles"."biografia" AS t1_r7, "profiles"."created_at" AS t1_r8, "profiles"."updated_at" AS t1_r9, "profiles"."hide_email" AS t1_r10, "profiles"."pic_file_name" AS t1_r11, "profiles"."pic_content_type" AS t1_r12, "profiles"."pic_file_size" AS t1_r13, "profiles"."pic_updated_at" AS t1_r14 FROM "usuarios" LEFT OUTER JOIN "profiles" ON "profiles"."usuario_id" = "usuarios"."id" WHERE "usuarios"."id" = $1 LIMIT 1 [["id", 12]]
USER CARGADO
Country Load (0.7ms) SELECT "countries".* FROM "countries" WHERE "countries"."id" = $1 LIMIT 1 [["id", 246]]
TEXTOS CARGADOS
Rendered usuarios/_main_frame.html.erb (12082.9ms)
(1.6ms) SELECT COUNT(DISTINCT "textos"."id") FROM "textos" LEFT OUTER JOIN "likes" ON "likes"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals_textos" ON "text_medals_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals" ON "text_medals"."id" = "text_medals_textos"."text_medal_id" LEFT OUTER JOIN "tags_textos" ON "tags_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "tags" ON "tags"."id" = "tags_textos"."tag_id" WHERE "textos"."usuario_id" = 12
SQL (1.9ms) SELECT DISTINCT "textos".id, textos.created_at AS alias_0 FROM "textos" LEFT OUTER JOIN "likes" ON "likes"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals_textos" ON "text_medals_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals" ON "text_medals"."id" = "text_medals_textos"."text_medal_id" LEFT OUTER JOIN "tags_textos" ON "tags_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "tags" ON "tags"."id" = "tags_textos"."tag_id" WHERE "textos"."usuario_id" = 12 ORDER BY textos.created_at DESC LIMIT 6 OFFSET 0
SQL (5.6ms) SELECT "textos"."id" AS t0_r0, "textos"."usuario_id" AS t0_r1, "textos"."titulo" AS t0_r2, "textos"."contenido" AS t0_r3, "textos"."idioma" AS t0_r4, "textos"."created_at" AS t0_r5, "textos"."updated_at" AS t0_r6, "textos"."is_borrador" AS t0_r7, "textos"."is_on_contest" AS t0_r8, "textos"."portada_file_name" AS t0_r9, "textos"."portada_content_type" AS t0_r10, "textos"."portada_file_size" AS t0_r11, "textos"."portada_updated_at" AS t0_r12, "textos"."contest_id" AS t0_r13, "textos"."views" AS t0_r14, "textos"."has_draft" AS t0_r15, "textos"."license_type" AS t0_r16, "likes"."id" AS t1_r0, "likes"."usuario_id" AS t1_r1, "likes"."texto_id" AS t1_r2, "likes"."created_at" AS t1_r3, "likes"."updated_at" AS t1_r4, "text_medals"."id" AS t2_r0, "text_medals"."name" AS t2_r1, "text_medals"."slogan" AS t2_r2, "text_medals"."created_at" AS t2_r3, "text_medals"."updated_at" AS t2_r4, "text_medals"."image_file_name" AS t2_r5, "text_medals"."image_content_type" AS t2_r6, "text_medals"."image_file_size" AS t2_r7, "text_medals"."image_updated_at" AS t2_r8, "tags"."id" AS t3_r0, "tags"."nombre" AS t3_r1, "tags"."created_at" AS t3_r2, "tags"."updated_at" AS t3_r3 FROM "textos" LEFT OUTER JOIN "likes" ON "likes"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals_textos" ON "text_medals_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals" ON "text_medals"."id" = "text_medals_textos"."text_medal_id" LEFT OUTER JOIN "tags_textos" ON "tags_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "tags" ON "tags"."id" = "tags_textos"."tag_id" WHERE "textos"."usuario_id" = 12 AND "textos"."id" IN (75, 74, 73, 70, 69, 68) ORDER BY textos.created_at DESC
CACHE (0.0ms) SELECT COUNT(DISTINCT "textos"."id") FROM "textos" LEFT OUTER JOIN "likes" ON "likes"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals_textos" ON "text_medals_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "text_medals" ON "text_medals"."id" = "text_medals_textos"."text_medal_id" LEFT OUTER JOIN "tags_textos" ON "tags_textos"."texto_id" = "textos"."id" LEFT OUTER JOIN "tags" ON "tags"."id" = "tags_textos"."tag_id" WHERE "textos"."usuario_id" = 12
Usuario Load (0.8ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
Profile Load (0.7ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
CACHE (0.1ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
CACHE (0.0ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
CACHE (0.1ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
CACHE (0.0ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
CACHE (0.1ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
CACHE (0.1ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
CACHE (0.0ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
CACHE (0.0ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
CACHE (0.1ms) SELECT "usuarios".* FROM "usuarios" WHERE "usuarios"."id" = $1 ORDER BY "usuarios"."id" ASC LIMIT 1 [["id", 12]]
CACHE (0.1ms) SELECT "profiles".* FROM "profiles" WHERE "profiles"."usuario_id" = $1 ORDER BY "profiles"."id" ASC LIMIT 1 [["usuario_id", 12]]
Rendered usuarios/_user_texts.html.erb (16760.5ms)
Rendered usuarios/show.html.erb within layouts/application (28889.5ms)
Completed 200 OK in 29246ms (Views: 28898.8ms | ActiveRecord: 44.1ms)
As you can see, the views take ages to render.
This the "_user_texts" partial.
<div class="ui grid">
<% #textos.each do |texto| %>
<div class="text row" text-pages="<%= #textos.total_pages%>">
<div class="five wide column">
<%= image_tag texto.portada.url(:medium), :class => "ui rounded medium left floated image text-cover" %>
</div>
<div class="eleven wide column">
<div class="row">
<h1 class="ui header">
<%= link_to text_name(texto), usuario_texto_path(texto.usuario.id, texto.id), :class => "title-format"%>
<div class="sub header subheader-format">
escrito por <%= text_author_image texto %><%= text_author_name texto %> el <%= humanize_creation_date(texto.created_at) %>
</div>
</h1>
</div>
<div class="tag-list row">
<div class="ui horizontal list">
<% if not texto.tags.empty? %>
<% texto.tags.each do |tag| %>
<div class="tag item">
<%= link_to tag.nombre, tag_path(tag.id), :class => "ui red large label" %>
</div>
<% end %>
<% end %>
</div>
</div>
</div>
</div>
<% end %>
</div>
<% if #textos.total_pages > #textos.current_page %>
<a id="more_texts" href="javascript:void(0)">
<span class="vertical"></span><span>Ver más</span>
</a>
<% end %>
EDIT: I am using pagination. Specifically the will_paginate gem. When I get to the bottom of the page, there's a button for fetching more results.
Can somebody give me insights on how could I make it faster? This is driving me nuts.
Thanks!

Answer 1

I would benchmark your query, seems pretty heavy to me. I think the focus should be on enhancing the performance of your sql query. I have no knowledge of the exact content, but I doubt you need this much intelligence in a single query.
For instance, you could add indices within your table to improve performance. You should also consider what attributes you really need and use select to define them. Less columns in your query yield faster results.
Finally, you are doing a lot of joins. It seems like you are pretty much joining all of your models. Left joins are really slow, because you go over all records. If you really need all these joins, it would be great if you could turn some of those left joins to inner joins . This would mean a massive improvement, because you have to check only relevant records.

Answer 2

The query is not actually run until you call .all or .each in the view even if you store the results in an instance variable in the controller. This can make it seem like the views are slow when actually it's something in the database.
Try putting some calls to benchmark different places in your view to see where the time is being used.
http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html#method-i-benchmark
For seeing what you're query is doing and spotting missing indexes etc. explain is handy.
http://guides.rubyonrails.org/active_record_querying.html#running-explain

Answer 3

Solved. With the help of the Bullet gem, I reformulate the way I was eager loading.
It turns out that everything done was, in practice, well done. The issue was that my partner was storing the images for paperclip in Dropbox.
Dropbox is most likely not made for this kind of requests, so the delay was because of this. We will change to Amazon's S3.
For the reader from the future: be advised! And check where are you storing your images.
Thanks to everybody!