Merge 0e10e79 into 343f6f7

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### 3.0.3
 - Optimize association eager loadable checks by caching information on the association's reflection.
+- Optimize association eager loading if we're only eager loading associations for a single model.
 
 ### 3.0.2
 - Fix destroyed model eager loading which accidentally broke in [#74](https://github.com/salsify/goldiloader/pull/74).

benchmark.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+cd "$( dirname "${BASH_SOURCE[0]}" )"
+
+echo `pwd`
+
+find benchmark/ -maxdepth 1 -type f -name "*_benchmark.rb" -exec bundle exec ruby {} \;

benchmark/main.rb → benchmark/main_benchmark.rb

@@ -1,23 +1,10 @@
 # frozen_string_literal: true
 
-$LOAD_PATH.push(File.expand_path('../lib', __dir__))
-
-require_relative 'lib/forking_benchmark'
-require 'active_record'
-
-ActiveRecord::Migration.verbose = false
+require_relative 'performance_helper'
 
 ForkingBenchmark.ips do |x|
-  x.time = 5
-  x.warmup = 2
-
   x.setup do
-    ActiveRecord::Base.establish_connection(
-      adapter: 'sqlite3',
-      database: ':memory:'
-    )
-
-    require_relative './db/schema.rb'
+    setup_database
 
     # Setup data
     blog_1 = Blog.create!

benchmark/performance_helper.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+$LOAD_PATH.push(File.expand_path('../lib', __dir__))
+
+require_relative 'lib/forking_benchmark'
+require 'active_record'
+
+ActiveRecord::Migration.verbose = false
+
+def setup_database
+  ActiveRecord::Base.establish_connection(
+    adapter: 'sqlite3',
+    database: ':memory:'
+  )
+
+  require_relative './db/schema.rb'
+end

benchmark/single_model_benchmark.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require_relative 'performance_helper'
+
+ForkingBenchmark.ips do |x|
+  x.setup do
+    setup_database
+
+    # Setup data
+    blog = Blog.create!
+    user = User.create!
+    Post.create!(author: user, blog: blog)
+  end
+
+  x.report("ActiveRecord: Single model's association") do
+    Post.first!.author
+  end
+
+  x.report("Goldiloader: Single model's association", setup: -> { require('goldiloader') }) do |iterations|
+    iterations.times do
+      Post.first!.author
+    end
+  end
+
+  x.compare!
+end

lib/goldiloader/active_record_patches.rb

@@ -133,11 +133,19 @@ def eager_loadable?
     def load_with_auto_include
       if loaded? && !stale_target?
         target
-      elsif auto_include?
+      elsif !auto_include?
+        yield
+      elsif owner.auto_include_context.size == 1
+        # Bypassing the preloader for a single model reduces object allocations by ~5% in benchmarks
+        result = yield
+        # As of https://github.com/rails/rails/commit/bd3b28f7f181dce53e872daa23dda101498b8fb4
+        # ActiveRecord does not use ActiveRecord::Relation#exec_queries to resolve association
+        # queries
+        Goldiloader::AutoIncludeContext.register_models(result)
+        result
+      else
         Goldiloader::AssociationLoader.load(owner, reflection.name)
         target
-      else
-        yield
       end
     end
   end

lib/goldiloader/auto_include_context.rb

@@ -4,6 +4,8 @@ module Goldiloader
   class AutoIncludeContext
     attr_reader :models
 
+    delegate :size, to: :models
+
     def initialize
       @models = []
     end