在这里真的需要一些帮助。努力显示包含大量数据的仪表板。

当处理 @ 2k 条记录时，平均 @ 2 秒。

MySql 控制台中的查询只需不到 3.5 秒即可返回 150k 行。 Ruby 中的相同查询从执行查询到所有对象准备就绪需要超过 4 分钟。

目标:在添加缓存服务器之前进一步优化数据。使用 Ruby 1.9.2、Rails 3.0 和 Mysql (Mysql2 gem)

问题:

• 使用哈希会影响性能吗？
• 我是否应该先将所有内容放入一个主哈希中，然后再处理我需要的数据？
• 还有什么我可以做的来帮助提高性能吗？

数据库中的行:

• GasStations 和美国人口普查有@ 150,000 条记录
• 人有@100,000条记录
• 汽车有@200,000 条记录
• FillUps 拥有@ 230 万

仪表板需要(基于过去 24 小时、上周等时间段的查询)。对于 JS，所有数据以 JSON 格式返回。

• 加油站，包含 FillUps 和美国人口普查数据(邮政编码、姓名、城市、人口)
• 填充最多的前 20 个城市
• 加油次数最多的 10 辆汽车
• 汽车按加满油箱的次数分组

代码(6 个月的样本。返回 @ 100k + 记录):

# for simplicity, removed the select clause I had, but removing data I don't need like updated_at, gas_station.created_at, etc. instead of returning all the columns for each table.
@primary_data = FillUp.includes([:car, :gas_staton, :gas_station => {:uscensus}]).where('fill_ups.created_at >= ?', 6.months.ago) # This would take @ 4 + minutes

# then tried

@primary_data = FillUp.find_by_sql('some long sql query...') # took longer than before.
# Note for others, sql query did some pre processing for me which added attributes to the return.  Query in DB Console took < 4 seconds.  Because of these extra attributes, query took longer as if Ruby was checking each row for mapping attributes

# then tried

MY_MAP = Hash[ActiveRecord::Base.connection.select_all('SELECT thingone, thingtwo from table').map{|one| [one['thingone'], one['thingtwo']]}] as seen http://stackoverflow.com/questions/4456834/ruby-on-rails-storing-and-accessing-large-data-sets
# that took 23 seconds and gained mapping of additional data that was processing later, so much faster

# currently using below which takes @ 10 seconds
# All though this is faster, query still only takes 3.5 seconds, but parsing it to the hashes does add overhead.
cars = {}
gasstations = {}
cities = {}
filled = {}

client = Mysql2::Client.new(:host => "localhost", :username => "root")
client.query("SELECT sum(fill_ups_grouped_by_car_id) as filled, fillups.car_id, cars.make as make, gasstations.name as name,  ....", :stream => true, :as => :json).each do |row|
  # this returns fill ups gouged by car ,fill_ups.car_id, car make, gas station name, gas station zip, gas station city, city population 
  if cities[row['city']]
    cities[row['city']]['fill_ups']  = (cities[row['city']]['fill_ups']  + row['filled'])
  else
    cities[row['city']] = {'fill_ups' => row['filled'], 'population' => row['population']}
  end
  if gasstations[row['name']]
    gasstations[row['name']]['fill_ups'] = (gasstations[row['name']]['fill_ups'] + row['filled'])
  else
    gasstations[row['name']] = {'city' => row['city'],'zip' => row['city'], 'fill_ups' => row['filled']}
  end
  if cars[row['make']]
    cars[row['make']] = (cars[row['make']] + row['filled'])
  else
    cars[row['make']] = row['filled']
  end
  if row['filled']
    filled[row['filled']] = (filled[row['filled']] + 1)
  else
    filled[row['filled']] = 1
  end
end

有以下型号:

def Person
 has_many :cars 
end

def Car
  belongs_to :person
  belongs_to :uscensus, :foreign_key => :zipcode, :primary_key => :zipcode
  has_many :fill_ups
  has_many :gas_stations, :through => :fill_ups
end

def GasStation
  belongs_to :uscensus, :foreign_key => :zipcode, :primary_key => :zipcode
  has_many :fill_ups
  has_many :cars, :through => :fill_ups
end

def FillUp
  # log of every time a person fills up there gas
  belongs_to :car
  belongs_to :gas_station
end

def Uscensus
  # Basic data about area based on Zip code
end

最佳答案

我不使用 RoR，但为仪表板返回 10 万行永远不会很快。我强烈建议构建或维护汇总表并在数据库中运行 GROUP BY 以在呈现之前汇总您的数据集。

关于mysql - 使用大数据集和 ruby，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11377289/