This document provides tips for optimizing Rails applications. It discusses using caching at the page, action, and fragment level. It also covers using background jobs to offload processing, optimizing database queries with includes and indexes, and leveraging assets like sprites, CSS, JavaScript minification, and gzipping. Metal and Rack middleware are presented as alternatives to Rails for high performance needs.

1. Otimizando Aplicações em Rails
essa palestra será rápida

2. Servidor
Active Record / SQL
Ruby / Rails
Cache
BackgrounDRb
Metal
HTML, JS & CSS

4. Nginx, Apache
balanceadores de carga

5. joeandmotorboat.com/2008/02/28/apache-vs-nginx-web-server-performance-deathmatch/

6. Mongrel, Thin, Passenger
servidores de aplicação

7. http://izumi.plan99.net/blog/index.php/2008/03/31/benchmark-passenger-mod_rails-vs-mongrel-vs-thin/

8. Active Record / SQL

9. INCLUDE
for list in List.all
... do some ...
for contact in list.contacts
... do some ...
end
end

10. INCLUDE
for list in List.all(:include => :contacts)
... do some ...
for contacts in list.contacts
... do some ...
end
end

11. ÍNDICES
Rails não adiciona índices nas
tabelas
EXPLAIN ANALYZE SELECT * FROM contacts WHERE
email = 'foo@bar.com';>> cost=0.00..25.38CREATE INDEX
contacts_email_idx ON contacts(email);>> cost=0.00..1.06

12. TABELAS CONSOLIDADAS
Newsletter#history
>> Buscava dados de mais de 100 mensagens (total de envios,
acessos, cliques, descadastros, informações geográficas...) em uma
view e apresentava um gráfico.
Tempo médio do método: 18s
CREATE TABLE messages_complete_history AS SELECT *
FROM view_messages_complete_history;
Tempo médio do método: 0.3s
>> Criação agendada para a madrugada com BackgroundRB

13. CSV EXPORT
COPY (SELECT * FROM contacts) TO 'path' WITH
DELIMITER ';' CSV HEADER
Muitas ordens de magnitude mais
rápido do que AR + FasterCSV

14. WORKING ON
postgres_timestamps plugin
sobrescreve comportamento de created_at e updated_at do
AR
cria defaults e triggers automaticamente nas migrações
benchmarks que fiz: de 2 a 5% mais rápido em 1000 inserts.
até 10% mais rápido em 1000 updates;
>> Prometo para ainda este ano!

15. Ruby / Rails

16. BENCHMARK
require 'benchmark'
Benchmark.bm do |x|
x.report('foo') { ... code ... }
x.report('bar') { ... code ... }
end

17. ||=
def calculate_something
@something = do_some_heavy_calculation
end

18. MEMOIZE
def calculate_something(*args)
do_some_heavy_calculation
end
memoize :calculate_something
calculate_something(1) #Hit
calculate_something(1) #Cache
calculate_something(1) #Cache
calculate_something(2) #Hit

19. RAILS STARTUP
# environment startup file
require 'geoip_city'
GEOIPDB = GeoIPCity::Database.new('file.dat')
# some controller or model
GEOIPDB.look_up(ip)

20. DICAS GERAIS
ids = @contacts.map(&:id) #bad
ids = @contacts.map{|c| c.id} #ugly, but good
str = str.gsub(/java/, 'ruby')#bad
str.gsub!(/java/, 'ruby') #good

21. Cache

22. PAGE CACHE
# site controller
caches_page :index

23. ACTION CACHE
# login controller
before_filter :get_client
caches_action :index

24. FRAGMENT CACHE
# some view
- cache :action_suffix => 'comments' do
= render :partial => 'comments'
# no controller...
def create_comment
...
expire_fragment :action => 'show_post',
:action_suffix => 'comments'
end

25. FRAGMENT CACHE
# some view
- cache :key => @contact.updated_at do
= render :partial => 'contact_info'
# Expira automático, mas gera alguns arquivos
...

26. HTTP CLIENT CACHE
fresh_when
:last_modified => @product.published_at.utc,
:etag => @article

27. CACHE-MONEY PLUGIN
http://github.com/nkallen/
cache-money/tree/master
>> Try it out and tell us...

28. Metal

29. METAL
class Go
def self.call(env)
if env["PATH_INFO"] =~ /^/go/view/(d+)/
id = $1
request = Rack::Request.new(env)
delivery = Delivery.find id
View.create :contact_id => delivery.
contact_id, :message_id => delivery.message_id, :ip
=> request.ip
delivery.contact.confirm!
[200, {"Content-Type" => "text/html"}, [""]]
else
[404, {"Content-Type" => "text/html"}, ["Not
Found"]]
end
end
end

30. METAL
2-5x faster
>> NÃO DEVERIA SE CHAMAR SPEED METAL?

31. BackgrounDRb

32. Pode executar tarefas em bg;
Pode agendar tarefas para
executar em bg;
Pode executar tarefas
periodicamente em bg;
Pode até conversar via TCP;

33. EXECUTANDO UMA TAREFA
class ContactsWorker < BackgrounDRb::MetaWorker
set_worker_name :contacts_worker
def delete(args)
total = args[:contacts].size
cache[:total] = total
cache[:curr] = 0
cache[:msg] = Contact.delete_many(args[:contacts]) do
cache[:curr] += 1
end
end
end
# start worker on controller
MiddleMan.worker(:contacts_worker).async_delete(:args =>
{:contacts => @contacts}, :job_key => @job_key)
# verify worker status via Ajax
t = MiddleMan.worker(:contacts_worker).ask_result(:total)
c = MiddleMan.worker(:contacts_worker).ask_result(:curr)
return render :json => [t, c]

34. EXECUTANDO UMA TAREFA
Média antes: 13s (muitas FKs!
milhares de contatos!)
Média depois: 0.1s (usuário pode
trabalhar durante processo)

35. EXECUTANDO UMA TAREFA AGENDADA
MiddleMan.worker(:messenger_worker)
.enq_send_messages(
:args => @message.id,
:scheduled_at => @message.scheduled_at,
:job_key => "message_#{@message.id}")

36. EXECUTANDO UMA TAREFA PERIÓDICA
# backgroundrb.yml
:schedules:
:table_cache_worker:
:table_cache:
:trigger_args: 0 30 4 * * * *

37. HTML, JS & CSS

38. CSS PLEASE DONT USE FONT TAG
SPRITES *
JSMIN
GZIP
HTTP CLIENT CACHE (304!)
return render :nothing => true, :status => 304

39. Cloud Storage e CDN
static.mailee.me