Question

我尝试使用SQL查询缓存大量数据（100 000），但缓存无效（写入缓存需要大约30秒，读取的时间相同）它）我做错了什么？我的配置变量已经设置为true

    query = "SELECT inscriptions.`id`, banners.`id`, banners.`name`, inscriptions.`registered_at`, 
                inscriptions.`synched_at`, inscriptions.`state`
         FROM inscriptions
         JOIN firm_offices
         ON inscriptions.`firm_office_1_id` = firm_offices.`id`
         JOIN firms
         ON firm_offices.`firm_id` = firms.`id`
         JOIN banners 
         ON firms.`banner_id` = banners.`id`
         GROUP BY inscriptions.`id`"

result = ActiveRecord::Base.connection.execute(query)
Rails.cache.fetch 'huge-array' do
  data = []
  result.each do |r| 
    data.push({ :id => r[0],
                 :banner_id => r[1],
                 :banner_name => r[2],
                 :registered_at => r[3],
                 :synched_at => r[4],
                 :state => r[5]})
  end
  data
end
@data = Rails.cache.read("huge-array")

Answer 1

将它全部移到fetch区块内：

@data ||= Rails.cache.fetch 'huge-array' do
  query = "SELECT inscriptions.`id`, banners.`id`, banners.`name`, inscriptions.`registered_at`, inscriptions.`synched_at`, inscriptions.`state`
     FROM inscriptions
     JOIN firm_offices
     ON inscriptions.`firm_office_1_id` = firm_offices.`id`
     JOIN firms
     ON firm_offices.`firm_id` = firms.`id`
     JOIN banners 
     ON firms.`banner_id` = banners.`id`
     GROUP BY inscriptions.`id`"  
  result = ActiveRecord::Base.connection.execute(query)
  data = []
  result.each do |r| 
    data.push({ :id => r[0],
             :banner_id => r[1],
             :banner_name => r[2],
             :registered_at => r[3],
             :synched_at => r[4],
             :state => r[5]})
  end
  data
end

注意：

您不需要将所有内容全部移动到块中，只需要昂贵的部分（例如execute(query)）。
您的大SQL查询看起来很容易转换为AR查询。您可能希望将其转换为AR查询，然后使用to_sql，如果结果更有效。

Answer 2

每次调用此函数时都无需运行查询和获取块。尝试像

这样的东西

@data = Rails.cache.read("huge-array")

if @data.empty?
  result = ActiveRecord::Base.connection.execute(query)

  @data = []

  result.each do |r| 
    @data.push({ :id => r[0],
             :banner_id => r[1],
             :banner_name => r[2],
             :registered_at => r[3],
             :synched_at => r[4],
             :state => r[5]})
  end 

  Rails.cache.write("huge-array", @data)
end

return @data

这样，如果缓存中不存在数据，您只需要进行昂贵的查询+数组创建。

Rails缓存不适用于手动查询？

2 个答案: