Activerecord test of simulteneous access serialization

serializer.rb

threads = []
(0..4).each do
threads << Thread.new {
row = XAuth::Variable.where(name: "current_member_id").first_or_create
row.with_lock do
  sleep(2)
  oldvalue = row.value.to_i
  newvalue = oldvalue + 1
  row.value = newvalue
  row.save!
  puts "#{Thread.current.object_id} ==> Old: #{oldvalue} , New val = #{newvalue}"
end
}

end

threads.each { |thr| thr.join }