Show the effects of rubygems source_index load on in-memory string size

rubygems_strings_gc.rb

RAW = true # flip me to make the logs readable, for interests sake.

def write_strings_to fn
  open(fn, 'w+') do |f|
    ObjectSpace.each_object do |o|
      f.send((RAW ? :print : :puts), o) if o.class == String
    end
  end
end

file = %w[strings_no_gems.log strings_gems_no_gc.log strings_gems.log]

GC.start
write_strings_to file[ 0 ]

require 'rubygems'
Gem.source_index.find { |_,spec| }
write_strings_to file[ 1 ]

GC.start
write_strings_to file[ 2 ]

last = File.size file[ 0 ]
file.each do |fn|
  cur = File.size(fn).to_f
  pcge = cur / last * 100
  puts "#%26s: %15d bytes, change: %8d%" % [fn, cur, pcge]
  last = cur
end

Before RubyGems 1.6:

#       strings_no_gems.log:            2214 bytes, change:      100%
#    strings_gems_no_gc.log:         5173464 bytes, change:   233670%
#          strings_gems.log:         4795559 bytes, change:       92%

After RubyGems 1.6:

#       strings_no_gems.log:            2214 bytes, change:      100%
#    strings_gems_no_gc.log:         1663044 bytes, change:    75114%
#          strings_gems.log:         1368931 bytes, change:       82%

N.B. You may need to run: https://gist.github.com/836462 to get the above effect (after installing rubygems 1.6/master).