在activeadmin上删除更快的300K关联对象（Rails 4，Activeadmin） [英] Delete faster 300K associated objects on activeadmin (Rails 4, Activeadmin)

问题描述

在创建模型交易时，我使用after_create在DealPrize表上创建奖品。

When creating a model Deal, I use an after_create to create prizes on the DealPrize table.

交易和DealPrize有一个属于/ has_many关系：一个交易具有

Deal and DealPrize have a belong to/has_many relations: a Deal has many Deal prizes and a Dealprize belongs to a Deal.

它的工作原理是：在Deal中，我有一个 prize-number列，并使用after_create，每次管理员创建新交易时，应用程序都会使用prize_number列，并在DealPrize表中创建此数量的奖品（根据需要插入尽可能多的行=>经常超过300,000）。

It works like this: inside Deal, I have a column 'prize-number' and I use an after_create so that every time the admin creates a new deal, the app takes this prize_number column, and create this volume of prizes (inserting as many rows as necessary=> often more than 300,000) inside the DealPrize table.

因此，我创建了一个交易，并且该应用程序自动创建了大量关联对象（奖品），例如300,000个。

So I create a Deal, and automatically, the app creates a huge number of associated objects (prizes) say 300,000.

问题是当我删除交易，我想删除所有相关的奖品。使用有效的管理员，我只需按删除即可，这要感谢 dependent：：destroy 。 如果奖赏号码大约为200，则可以正常工作，但对于300K关联的对象/行，则非常慢。这需要15分钟。

The problem is when I delete the Deal, I want to delete all associated prizes. With active admin, I just press 'delete' and it works fine thanks to the dependent: :destroy. If the prize number is like 200, it works fine but for 300K associated objects/rows, it is very slow. It takes 15 minutes.

如何加快速度？我如何覆盖/增强ActiveAdmin删除功能以更快地删除300K关联的奖品？

我可以使用交易还是批量删除？

Could I use transactions or batched deletes ?

模态Deals.rb

has_many   :deal_prizes,  dependent: :destroy 

after_create :create_deal_prizes

CONNECTION = ActiveRecord::Base.connection.raw_connection

    def create_deal_prizes
      begin 
        CONNECTION.describe_prepared('yokoatxz')
      rescue PG::InvalidSqlStatementName
        CONNECTION.prepare('yokoatxz', 'INSERT INTO deal_prizes (deal_id,created_at,updated_at,admin_user_id) values ($1, $2, $3, $4)') 
      end

      Deal.transaction do  
        self.prizes_number.times do |i| 
          CONNECTION.exec_prepared('yokoatxz',  [ { value: self.id},
                                                  { value: '2009-01-23 20:21:13' },
                                                  { value: '2009-01-23 20:21:13' },
                                                  { value: self.admin_user_id }
                                                ] )
        end
      end
    end

感谢您的帮助，
Mathieu

Thanks for your help, Mathieu

推荐答案

您会发现：

has_many :deal_prizes, dependent: :delete_all

...会更快，因为它会发出一条SQL语句：

... would be much faster, as it would issue a SQL statement to:

delete from deal_prizes where deal_id = 123;

不会进行回调，但这只是性能魔术的全部。

No callbacks would be made, but that's just all part of the performance magic.

请参阅： Rails：dependent => ：destroy VS：dependent => ：delete_all

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