Ticket #3238: db_benchmark.rb

#!/usr/bin/ruby
# Place this benchmark in activerecord/benchmarks
# Replace base.rb with patched version to see results for new ActiveRecord::Base
#
# My Results (for MySQL):
#
# Using old base.rb (100 runs):
#               user     system      total        real
# No save  :  0.270000   0.020000   0.290000 (  0.402543)
# With save:  3.600000   0.260000   3.860000 (  5.091319)
#
# Modified (patched, track_inplace_modifications = false) base.rb (100 queries):
#               user     system      total        real
# No save  :  0.300000   0.020000   0.320000 (  0.390043)
# With save:  1.970000   0.120000   2.090000 (  2.420767)
#
# Modified (patched, track_inplace_modifications = true) base.rb (100 queries):
#               user     system      total        real
# No save  :  0.400000   0.020000   0.420000 (  0.598095)
# With save:  3.300000   0.230000   3.530000 (  4.495584)
#
# You can see that without in place modifications, the performance increase over SQL queries is
# very significant (2 seconds on just 100 runs). There's also no slowdown on reading.
# Of course, it's better to focus on the worst case scenario, so let's:
#
# Changes with in place modification tracking turned on indicate a slight slowdown in reading values 
# (each record reads _all_ attributes and doubles memory size) but actually shows a slight 
# increase in the saving run. This means that the SQL query optimization is there, and visible too-- 
# 0.5 sec increase on only 100 runs. And it outweighs the performance loss, so all in all, it's a good thing.
#
# By the way, if you're curious, the algorithm runs in O(n), meaning increasing the amount
# of queries to 1000 will raise the benchmark times by approx. 10-- but the relationships stay. 
# Try it!
#
# Example (unpatched base.rb) for 1000 runs:
#               user     system      total        real
# No save  :  2.580000   0.180000   2.760000 (  3.709316)
# With save: 36.130000   2.610000  38.740000 ( 55.599461)
#
# Example (patched base.rb, track_inplace_modifications = false) for 1000 runs:
#               user     system      total        real
# No save  :  3.060000   0.160000   3.220000 (  3.815927)
# With save: 19.580000   1.260000  20.840000 ( 25.586016)
#
# Example (patched base.rb, track_inplace_modifications = true) for 1000 runs:
#               user     system      total        real
# No save  :  4.080000   0.210000   4.290000 (  5.359764)
# With save: 32.920000   2.260000  35.180000 ( 46.913362)
#

$:.unshift(File.dirname(__FILE__) + '/../lib')
if ARGV[2]
  require 'rubygems'
  require_gem 'activerecord', ARGV[2]
else
  require 'active_record'
end
QUOTED_TYPE = '`type`'
require '../test/fixtures/company'

ActiveRecord::Base.establish_connection(:adapter => "mysql", :database => "activerecord_unittest")

require 'benchmark'
p = Proc.new do |do_save|
  1000.times do
    companies = Company.find(:all)
    companies.each do |c| 
      c.class.column_names.each {|col| c[col] } 
      c.save if do_save
    end
  end
end
Benchmark.bm do |b|
  b.report("No save  :") { p.call(false) }
  b.report("With save:") { p.call(true) }
end