Question

我目前正在攻击一个事件站点，并且从来没有遇到过优化查询/扩展我的数据库的问题，因为从来没有那么多的数据，但现在数据库中有近百万行，而且需要大约15,000行m / s用于呈现事件的提要，特别是部分（在每个_event.html.erb中）非常慢的部分是显示您当前关注的所有用户的事件。我已经查找了很多提高性能的可能性，包括急切加载，索引，内存缓存等等......但是想知道如何重写它以便更快地执行？谢谢！

_attending.html.erb

<% if user_signed_in? %>
        <% @rsvp = Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going') %>
        <% if @rsvp.count == 0 %>
            <%= eventcount(event) %> going.
        <% elsif @rsvp.count == 1 %>
            <% if eventcount(event) - 1 == 0 %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> is going.
                <% end %>
            <% else %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 1 %> going.
              <% end %>
            <% end %>
        <% elsif @rsvp.count == 2 %>
            <% if eventcount(event) - 2 == 0 %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and
                <% end %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[1..1].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> are going.
                <% end %>
            <% else %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
              <% end %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[1..1].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 2 %> going.
              <% end %>
                <% end %>
        <% elsif @rsvp.count == 3 %>
            <% if eventcount(event) - 3 == 0 %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
                <% end %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[1..1].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>, and
                <% end %>
                <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[2..2].each do |f| %>
                    <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> are going.
                <% end %>
            <% else %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[0..0].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
              <% end %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[1..1].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
              <% end %>
              <% Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')[2..2].each do |f| %>
                  <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 3 %> are going.
              <% end %>
            <% end %>
            <% end %>
    <% else %>
        <%= eventcount(event) %> going.
    <% end %>

RSVP架构

create_table "rsvps", :force => true do |t|
  t.string    "status"
  t.integer   "event_id"
  t.integer   "voter_id"
  t.string    "voter_name"
  t.string    "voter_type"
  t.timestamp "created_at", :null => false
  t.timestamp "updated_at", :null => false
end

add_index "rsvps", ["voter_id", "voter_type", "event_id"], :name => "fk_one_rsvp_per_user_per_entity", :unique => true
add_index "rsvps", ["voter_id", "voter_type"], :name => "index_rsvps_on_voter_id_and_voter_type"

关系模式

create_table "relationships", :force => true do |t|
  t.integer   "follower_id"
  t.integer   "followed_id"
  t.timestamp "created_at",  :null => false
  t.timestamp "updated_at",  :null => false
end

add_index "relationships", ["followed_id"], :name => "index_relationships_on_followed_id"
add_index "relationships", ["follower_id"], :name => "index_relationships_on_follower_id"

用户模型的相关部分

has_many :relationships, :foreign_key => "follower_id",
:dependent => :destroy

has_many :following, :through => :relationships, :source => :followed

has_many :reverse_relationships, :foreign_key => "followed_id",
       :class_name => "Relationship",
       :dependent => :destroy
has_many :followers, :through => :reverse_relationships, :source => :follower

Answer 1

如果大型数据库是RSVP：

你在部分中对数据库进行了非常大的调用，只尝试减少n次调用Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')，然后在不同的情况下进行处理。这可以对性能有所帮助（如果你有一个大的数据库，每次在大型数据库中调用.where都是一个复杂的过程）。重用变量@rsvp。

Answer 2

只需快速清理并遵循@damoiser所说的你应该将你的观点重构为这样的东西。

<强> _attending.html.erb

<% if user_signed_in? %>
  <% @rsvp = get_rsvps %>
  <% if @rsvp.count == 0 %>
    <%= eventcount(event) %> going.
  <% elsif @rsvp.count == 1 %>
    <% if eventcount(event) - 1 == 0 %>
      <% @rsvp[0..0].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> is going.
      <% end %>
    <% else %>
      <% @rsvp[0..0].each do |f| %>
          <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 1 %> going.
      <% end %>
    <% end %>
  <% elsif @rsvp.count == 2 %>
    <% if eventcount(event) - 2 == 0 %>
      <% @rsvp[0..0].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and
      <% end %>
      <% @rsvp[1..1].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> are going.
      <% end %>
    <% else %>
      <% @rsvp[0..0].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
      <% end %>
      <% @rsvp[1..1].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 2 %> going.
      <% end %>
    <% end %>
  <% elsif @rsvp.count == 3 %>
    <% if eventcount(event) - 3 == 0 %>
      <% @rsvp[0..0].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
      <% end %>
      <% @rsvp[1..1].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>, and
      <% end %>
      <% @rsvp[2..2].each do |f| %>
          <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> are going.
      <% end %>
    <% else %>
      <% @rsvp[0..0].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
      <% end %>
      <% @rsvp[1..1].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %>,
      <% end %>
      <% @rsvp[2..2].each do |f| %>
        <%= link_to User.find(f.voter_id).name, User.find(f.voter_id).slug %> and <%= eventcount(event) - 3 %> are going.
      <% end %>
    <% end %>
  <% end %>
<% else %>
  <%= eventcount(event) %> going.
<% end %>

你也应该有这样的帮手：

<强> some_helper.rb

module SomeHelper
  def get_rsvps
    Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')
  end
end

巨大注意：这段代码仍然没有任何好处。我仍然认为有很多重构要做。就像link_to帮助器上的[0..0] .each和[1..1] .each和很多代码重复一样。但这样可以获得一些性能，因为你只是在调用rsvps并重用你在@rsvp中存储的内容。

优化activerecord查询以显示事件的与会者

2 个答案: