Tag Archives: Threads

Testing SuckerPunch/Celluloid vs ActiveRecord Transactions

Celluloid runs in a new thread, so it runs on a new transaction. Therefore we cannot test what was done in this transaction.

If you are not using any Celluloid callbacks then a simple unthreaded baseclass can help:

class BackgroundJobTestable
  def perform
    ...
end

class BackgroundJob < BackgroundJobTestable
  include SuckerPunch::Job
  workers 2
end

An alternative way to fix this is to disable AR multithreading support via a mocking library like mocha … this will break any code that truly runs in parallel, but if you only run 1 code path at a time this should work fine.

ActiveRecord::Base.stubs(connection: ActiveRecord::Base.connection)

Micro Benchmark fastest threadsave Accessor

While working on my new Fast-Gettext i needed a really fast way load the current translations, since they are needed every time, and must be stored inside Thread.current for Thread-safety. So i came up with a small micro benchmark for fastest accessor.

This test is separate into single-access and generic access (just one value / n values)

Results

Ruby 1.8.7
generic:
  Symbol: 1.06s
  String concat: 1.73s
  String add: 1.69s
  String insert: 1.47s
single:
  Symbol: 0.67s
  String: 0.96s

So as we can see, stick to symbols!

Test

require 'benchmark'
BASELINE = 0
def test
  result = Benchmark.measure {1_000_000.times{ yield }}
  result.to_s.strip.split(' ').first.to_f - BASELINE
end

BASELINE = (test{})
Thread.current[:library_name]={}
other = "x"

puts "generic:"
puts "Symbol: #{test{Thread.current[:library_name][:just_a_symbol]}}s"
puts "String concat: #{test{Thread.current["xxxxxx"<<other.to_s]}}s"
puts "String add: #{test{Thread.current["xxxxxx"+other.to_s]}}s"
puts "String insert: #{test{Thread.current["xxxxxx#{other}"]}}s"

puts "single:"
puts "Symbol: #{test{Thread.current[:long_unique_symbol]}}s"
puts "String: #{test{Thread.current["xxxxxx"]}}s"