Starting this thread to get things going!
I’ve just added benchmarks for default_scope and the results are quite shocking that I’ll review it on my local machine tomorrow.
http://rubybench.org/rails/rails/releases?result_type=activerecord/sqlite3_finders_all
There are still some benchmarks that Kirs has written but I’ve yet to activate them yet.
That does looks a bit odd, was expecting a regression in 4.2.0 not in 4.10
@sam I have verified and am getting the same results on my local machine.
require 'bundler/setup'
require 'rails'
require 'active_record'
require 'stackprof'
require_relative 'support/benchmark_rails.rb'
ActiveRecord::Base.establish_connection(
adapter: 'sqlite3',
database: ':memory:'
)
ActiveRecord::Migration.verbose = false
ActiveRecord::Schema.define do
create_table :users, force: true do |t|
t.string :name, :email
t.boolean :admin
t.timestamps null: false
end
end
class User < ActiveRecord::Base
default_scope { where(admin: true) }
end
admin = true
1000.times do
attributes = {
name: "Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
email: "foobar@email.com",
admin: admin
}
User.create!(attributes)
admin = !admin
end
# Benchmark.rails("activerecord/sqlite3_finders_all", time: 10) do
StackProf.run(mode: :cpu, out: 'after.dump') do
100000.times do
User.all
end
end
clearly an anomaly on 3.2.4 its destroying the graph 
Yea I noticed that and re-ran the benchmark again. Same results. We should investigate xD
I just ran the benchmark on the local machine. Didn’t seem like there was anything wrong. User.all returns an array on Rails 3.2.4.
We need some sort of solution here, if there is an outlier result graph should still be usable.
Added mysql and postgres benchmarks.
Hmm just noticed that the anomaly disappear… http://rubybench.org/rails/rails/releases?result_type=activerecord/sqlite3_finders_all
