From 69de09c5cee19d63400c4b62d2ebeac5a89eb14d Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Mon, 7 Sep 2015 15:13:00 +0800
Subject: PERF: Don't create a Relation when it is not needed.
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Benchmark script used:
```
begin
require 'bundler/inline'
rescue LoadError => e
$stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
raise e
end
gemfile(true) do
source 'https://rubygems.org'
gem 'rails', path: '~/rails' # master against ref "f1f0a3f8d99aef8aacfa81ceac3880dcac03ca06"
gem 'arel', github: 'rails/arel', branch: 'master'
gem 'rack', github: 'rack/rack', branch: 'master'
gem 'sass'
gem 'sprockets-rails', github: 'rails/sprockets-rails', branch: 'master'
gem 'sprockets', github: 'rails/sprockets', branch: 'master'
gem 'pg'
gem 'benchmark-ips'
end
require 'active_record'
require 'benchmark/ips'
ActiveRecord::Base.establish_connection('postgres://postgres@localhost:5432/rubybench')
ActiveRecord::Migration.verbose = false
ActiveRecord::Schema.define do
create_table :users, force: true do |t|
t.string :name, :email
t.timestamps null: false
end
end
class User < ActiveRecord::Base; end
attributes = {
name: "Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
email: "foobar@email.com",
}
1000.times { User.create!(attributes) }
Benchmark.ips(5, 3) do |x|
x.report('all') { User.all }
end
key =
if RUBY_VERSION < '2.2'
:total_allocated_object
else
:total_allocated_objects
end
before = GC.stat[key]
User.where(name: "Lorem ipsum dolor sit amet, consectetur adipiscing elit.")
after = GC.stat[key]
puts "Total Allocated Object: #{after - before}"
```
Before:
```
Calculating -------------------------------------
all 17.569k i/100ms
-------------------------------------------------
all 190.854k (± 3.3%) i/s - 966.295k
Total Allocated Object: 85
```
After:
```
Calculating -------------------------------------
all 22.237k i/100ms
-------------------------------------------------
all 262.715k (± 5.5%) i/s - 1.312M
Total Allocated Object: 80
```
---
activerecord/lib/active_record/scoping/default.rb | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
(limited to 'activerecord/lib')
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index a1adf8e3ee..6454f17fdb 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -99,12 +99,13 @@ module ActiveRecord
self.default_scopes += [scope]
end
- def build_default_scope(base_rel = relation) # :nodoc:
+ def build_default_scope(base_rel = nil) # :nodoc:
return if abstract_class?
if !Base.is_a?(method(:default_scope).owner)
# The user has defined their own default scope method, so call that
evaluate_default_scope { default_scope }
elsif default_scopes.any?
+ base_rel ||= relation
evaluate_default_scope do
default_scopes.inject(base_rel) do |default_scope, scope|
default_scope.merge(base_rel.scoping { scope.call })
--
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