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我目前在一个活动网站上进行黑客攻击，过去从未遇到过优化查询/扩展我的数据库的问题，因为从来没有那么多数据，但现在数据库中有近一百万行，它需要大约 15,000 m/s呈现事件的提要，特别是非常慢的部分（在每个 _event.html.erb 内）是显示您当前关注的所有正在参加该事件的用户的位置。我已经寻找了很多提高性能的可能性，包括预加载、索引、内存缓存等……但是想知道如何重写它以更快地执行？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 的架构

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
4

2 回答 2

0

如果大数据库是 RSVP：

您在部分中对 db 进行了非常大的调用，尝试Rsvp.where(:voter_id => current_user.following, :event_id => event.id, :status => 'going')仅减少一次 n 调用，然后在不同情况下对其进行处理。这对性能有一点帮助（如果您有一个大数据库，那么每次在大数据库中调用 .where 都是一个复杂的过程）。重新使用变量@rsvp。

于 2012-10-25T14:01:47.667 回答
0

只需快速清理并遵循@damoiser 所说的，您应该将您的视图重构为这样的东西。

_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 %>

您还应该有一些这样的助手：

some_helper.rb

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

巨大的注意：这个代码仍然没有任何好处。我仍然认为有很多重构要做。就像 [0..0].each 和 [1..1].each 以及 link_to 助手上的大量代码重复。但这应该会给您带来一些性能，因为您只是在调用 rsvps 并重用您存储在 @rsvp 中的内容。

于 2012-10-25T14:21:57.587 回答