Question

我有一些计数器存储在REDIS中，可以根据customer.rb中的状态更改进行更新。我需要存储的东西是：

1）与用户关联的客户数量（用户has_many客户） 2）状态为（使用aasm_state）'open'或'声明'的客户数 3）状态为（使用aasm_state）'open

的客户数

每当客户的状态发生变化时，我都会相应地增加/减少redis计数器。然而，无论我尝试过什么，计数似乎总是在一段时间后关闭。

我正在使用Sidekiq，但我不认为这是一个并发问题，因为REDIS不应该遇到并发问题，对吧？

这是我的计数更新程序方法：

  def reset_stats
    if aasm_state_was == 'open' && aasm_state == 'claimed' # open => assigned
      # update company and user
      user.redis_increment_my_customers_length
      company.redis_decrement_open_customers_length

    elsif user_id_changed? && aasm_state_was == 'claimed' && aasm_state == 'claimed' # assigned => assigned
      # update users (assigner and assignee)
      user_was = User.find(user_id_was)
      user.redis_increment_my_customers_length
      user_was.redis_decrement_my_customers_length

    elsif aasm_state_was == 'claimed' && aasm_state == 'closed' # assigned => closed
      # update company and user
      user_was = User.find(user_id_was)
      user_was.redis_decrement_my_customers_length
      company.redis_decrement_all_customers_length

    elsif aasm_state_was == 'closed' && aasm_state == 'claimed' # closed => assigned
      # update company and user
      user.redis_increment_my_customers_length
      company.redis_increment_all_customers_length

    elsif aasm_state_was == 'closed' && aasm_state == 'open' # closed => open
      # update company
      company.redis_increment_all_customers_length
      company.redis_increment_open_customers_length

    elsif aasm_state_was == 'open' && aasm_state == 'closed' # open => closed
      # update company
      company.redis_decrement_all_customers_length
      company.redis_decrement_open_customers_length

    end

并在user.rb中：

def redis_length_key
    "my_customers_length_for_#{id}"
  end

  def set_my_customers_length(l)
    RED.set(redis_length_key, l)
    l.to_i
  end

  def redis_increment_my_customers_length
    RED.get(redis_length_key) ? RED.incr(redis_length_key) : my_customers_length
  end

  def redis_decrement_my_customers_length
    RED.get(redis_length_key) ? RED.decr(redis_length_key) : my_customers_length
  end

  def my_customers_length
    if l = RED.get(redis_length_key)
      l.to_i
    else
      set_my_customers_length(my_customers.length)
    end
  end

并在company.rb中：

def open_customers
    customers.open
  end

  def redis_open_length_key
    "open_customers_length_for_#{id}"
  end

  def set_open_customers_length(l)
    RED.set(redis_open_length_key, l)
    l.to_i
  end

  def redis_increment_open_customers_length
    RED.get(redis_open_length_key) ? RED.incr(redis_open_length_key) : open_customers_length
  end

  def redis_decrement_open_customers_length
    RED.get(redis_open_length_key) ? RED.decr(redis_open_length_key) : open_customers_length
  end

  def open_customers_length
    if l = RED.get(redis_open_length_key)
      return l.to_i
    else
      set_open_customers_length(open_customers.length)
    end
  end

  def redis_all_length_key
    "all_customers_length_for_#{id}"
  end

  def set_all_customers_length(l)
    RED.set(redis_all_length_key, l)
    l
  end

  def redis_increment_all_customers_length
    RED.get(redis_all_length_key) ? RED.incr(redis_all_length_key) : all_customers_length
  end

  def redis_decrement_all_customers_length
    RED.get(redis_all_length_key) ? RED.decr(redis_all_length_key) : all_customers_length
  end

  def all_customers_length
    if l = RED.get(redis_all_length_key)
      l.to_i
    else
      set_all_customers_length(open_or_claimed_customers.length)
    end
  end

  def open_or_claimed_customers
    customers.open_or_claimed
  end

我正在努力实现的目标是否有更好的模式？这非常令人沮丧，因为一段时间后，计数似乎总是变得不正确。请帮忙！

Answer 1

您在致电RED.set(redis_open_length_key, l)和致电时间val strings = List("hi","I","am","here") //this list is a stream of words from Twitter val mystrings = strings.filter(word => !word.contains("I" || "sam") // I need filter out certain stop words之间存在竞争条件。

两个进程开始。
my_customers_length为5。
第一个进程进行第二次调用并将Redis设置为6.
第二个进程进行第二次调用并再次将Redis设置为6。
Redis值实际上应为7。

考虑使用Redis的INCR和DECR函数以原子方式更新值。

Answer 2

你的竞争条件如下：

RED.get(redis_all_length_key) ? RED.incr(redis_all_length_key) : all_customers_length

在读取和写入Redis之间不能做任何逻辑。

似乎无法保持redis计数器的正确性

2 个答案: