为什么不锁门!阻止其他人更新?

class Plan < ActiveRecord::Base
  def testing
    self.with_lock do
      update_columns(lock: true)
      byebug
    end
  end

  def testing2
    self.lock!
    byebug
  end
end

我打开了两个rails控制台。

在第一个控制台中:

p = Plan.create
=> (basically success)
p.id
=> 12
p.testing2
(byebug) # simulation of halting the execution,
(BYEBUG) # I just leave the rails console open and wait at here. I expect others won't be able to update p because I still got the lock.

在第二个控制台上:

p = Plan.find(12)
=> (basically said found)
p.name = 'should not be able to be stored in database'
=> "should not be able to be stored in database"
p.save!
=> true # what????? Why can it update my object? It's lock in the other console!

lock! 在里面 testing2 不锁的时候 with_lock 不起作用?