Ticket #8976: perform_exist.rb

require 'benchmark'

def do_benchmark
  n = 10000
  Benchmark.bm do |x|
    # Existing item by id
    x.report { n.times do Item.exists?(1); end }
    
    # fake fake id. Gimme false
    x.report { n.times do Item.exists?(1384); end }
    
    # Existing item by conditions
    x.report { n.times do Item.exists?(:name => "sunshine"); end }
    
    # Existing item by conditions matching multiple records
    x.report { n.times do Item.exists?((['name LIKE ?', "%shine%"])); end }

    # fake fake name. Gimme false
    x.report { n.times do Item.exists?(:name => "moonlight"); end }
  end
end

puts "Existing AR implementation"
do_benchmark

class ActiveRecord::Base
  def self.exists?(id_or_conditions)
    !find(:first, :select => "#{table_name}.#{primary_key}", :conditions => expand_id_conditions(id_or_conditions)).nil?   
  rescue ActiveRecord::ActiveRecordError
    false
  end
end

puts "Josh's Implementation"
do_benchmark

class ActiveRecord::Base
  def self.exists?(id_or_conditions)
    !find(:all, :select => "#{table_name}.#{primary_key}", :conditions => expand_id_conditions(id_or_conditions), :limit => 1).empty?
  end
end

puts "Lifo's Implementation"
do_benchmark

# $ script/runner lib/perform_exist.rb 
# Existing AR implementation
#       user     system      total        real
#   7.130000   0.320000   7.450000 (  8.952531)
#   6.470000   0.300000   6.770000 (  8.341876)
#   6.960000   0.290000   7.250000 (  8.596609)
#   6.710000   0.300000   7.010000 (  8.178951)
#   6.470000   0.290000   6.760000 (  7.986819)
# Josh's Implementation
#       user     system      total        real
#   4.780000   0.290000   5.070000 (  6.780793)
#   4.410000   0.280000   4.690000 (  5.622038)
#   4.800000   0.290000   5.090000 (  6.184860)
#   4.500000   0.290000   4.790000 (  5.957613)
#   4.420000   0.260000   4.680000 (  5.640687)
# Lifo's Implementation
#       user     system      total        real
#   4.730000   0.280000   5.010000 (  6.459801)
#   4.330000   0.280000   4.610000 (  5.523227)
#   4.680000   0.280000   4.960000 (  5.908463)
#   4.290000   0.270000   4.560000 (  5.482114)
#   4.380000   0.270000   4.650000 (  5.612552)