ruby_heap_monitor¶ ↑

This is a patch for ruby to enable to monitor the live objects in the heap.

Install¶ ↑

Suppose that your ruby’s directory name is “ruby18”, you can install this patch as follows.

cp -pr ruby18 ruby18.orig
cp -p diff.ruby_heap_monitor ruby18
cd ruby18
patch -p1 < diff.ruby_heap_monitor
make
make install
cd ..
rm -rf ruby18.orig # if install.ok?

Usage¶ ↑

After installing this patch, you can call ObjectSpace.print_object. This method recieves a opened File object and dumps the live objects in the heap into the file. Also You can filter the objects by their created time with sending the optional argument.

Example¶ ↑

If you run the following sample code with the patched ruby, you’ll get the file ‘hoge.log’.

class Foo
  @@cvar = 'foofoo'
  attr_accessor :int, :float, :array, :hash

  def initialize(name)
    @name = name
    @proc = lambda { a = 'aaaa'; b = 'bbbb' }
  end

  def re
    @name =~ /(T*s)/
  end
end

sleep 10 

foo = Foo.new('This is Foo')
foo.int = 99999999999999999999999999999999999999999
foo.float = 0.123456789
foo.array = ['first', 'second', 'third']
foo.hash = { 'one' => 'Jan', 'two' => 'Feb', 'three' => 'Mar' }
foo.re

File.open('hoge.log', 'w') do |f|
  Hoge = Struct.new('Hoge', :cat, :dog, :monkey)
  hoge = Hoge.new(foo, foo, f)

  # dump the objects in the heap.
  ObjectSpace.print_object(f, 5)  # You only get the objects created within 5 seconds.
end

You can see the dumped informations inside ‘hoge.log’ like the below.

        :
==========================================
filename:  hoge.rb
linenum:   26
time:      2009-10-04 23:17
class:     Struct::Hoge
object_id: 0xB7E4CFA5
inspect:   #<struct Struct::Hoge cat=#<Foo:0xb7e4d490 @name="This is Foo", @array=["first", "second", "third"], @float=0.123456789, @int=99999999999999999999999999999999999999999, @proc=#<Proc:0xb7e4e8cc@hoge.rb:7>, @hash={"three"=>"Mar", "two"=>"Feb", "one"=>"Jan"}>, dog=#<Foo:0xb7e4d490 @name="This is Foo", @array=["first", "second", "third"], @float=0.123456789, @int=99999999999999999999999999999999999999999, @proc=#<Proc:0xb7e4e8cc@hoge.rb:7>, @hash={"three"=>"Mar", "two"=>"Feb", "one"=>"Jan"}>, monkey=#<File:hoge.log>>
referring_to:
    0xB7E4D491
    0x00000023
    0xB7E4D491
==========================================
        :
==========================================
filename:  hoge.rb
linenum:   16
time:      2009-10-04 23:17
class:     Bignum
object_id: 0xB7E4E371
inspect:   99999999999999999999999999999999999999999
==========================================
filename:  hoge.rb
linenum:   16
time:      2009-10-04 23:17
type:      Node
object_id: 0xB7E4E38D
nodetype:  0x67
referring_to:
    0xB7E4E3A9
    0xB7E4E339
==========================================
        :

Problems¶ ↑

• In the dumped file, references to the objects in the block are something wrong.

• I want to remove the node informations from the objects dump. But only they seem to refer the objects in the block. Do any heap objects other than nodes refer the objects in the block ?

• I tested this patch with only Ruby 1.8.5 and 1.8.7 (in Rails).

Author¶ ↑

Mitsunori Komatsu