Rails4：如何獲取ActiveRecord連接池中的空閒連接數？

Question

我可以看到爲Rails 5（http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/ConnectionPool.html#method-i-stat）定義的stat方法。這會報告各種狀態下的連接。這在Rails 4或更早版本中不可用。有沒有其他的方法來獲取Rails 4中的信息？

Answer 1

您可以修補同在Rails4

方法star這是你可以在Rails4加也。

ActiveRecord::Base.connection_pool.synchronize do 
    { connections: ActiveRecord::Base.connection_pool.connections.size } 
end 

=> {：連接=> 1}

Rails5 stat定義

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb, line 583 
def stat 
    synchronize do 
    { 
     size: size, 
     connections: @connections.size, 
     busy: @connections.count { |c| c.in_use? && c.owner.alive? }, 
     dead: @connections.count { |c| c.in_use? && !c.owner.alive? }, 
     idle: @connections.count { |c| !c.in_use? }, 
     waiting: num_waiting_in_queue, 
     checkout_timeout: checkout_timeout 
    } 
    end 
end