Rails Race Condition - Pessimistic Locking

rails_race_condition.rb

def update(i)
  ActiveRecord::Base.transaction do
    sleep(0.5)
    id = 5928598

    person = Person.lock.find(id)
    person.name = "Rodolfo#{i}"
    person.save!
  end
end

threads = [] 


ActiveRecord::Base.transaction do
  id = 5928598
  person = Person.lock.find(id)

  10.times do |i|
    threads << Thread.new { update(i) }
  end

  sleep(5)

  person.name = "Rodolfo"
  person.save!
end

threads.each(&:join)