Finalizing(?) instance variables

ruby-talk
1

Hi,

I finished writing a fairly large Ruby application and I was careless
with cleaning up variables. My objects contain references to large
ActiveRecord objects (instance variables), and I wanted to make sure
that I don't specifically need to set these instance variables to nil
when they're not used anymore: as long as I set the parent object to
nil, since there will be no reference to its instance variables, the
parent object and its instance variable objects should be removed by
the GC. Is this correct?

For example, I might have this program:

class Blah

  attr_accessor :arr

  def initialize
    @arr = Array.new(10000000, 'TEST')
  end

end

while (true)
  b = Blah.new
  sleep 5
end

I noticed that the memory on my machine only goes up at the beginning
of the program, and then stays constant. I can only conclude that each
time the loop executes, the old b.arr becomes unreferenced and is
garbage collected and that the new b.arr is allocated (thus memory
usage is the same).
I just need someone to confirm this, since my program freezes after
running more than 24hours and I can't find the (memory) leakage.

Thanks,
Tiberiu

2

Hi,

I finished writing a fairly large Ruby application and I was careless
with cleaning up variables. My objects contain references to large
ActiveRecord objects (instance variables), and I wanted to make sure
that I don't specifically need to set these instance variables to nil
when they're not used anymore: as long as I set the parent object to
nil, since there will be no reference to its instance variables, the
parent object and its instance variable objects should be removed by
the GC. Is this correct?

Correct. Ruby does mark and sweep CG AFAIK.

For example, I might have this program:

class Blah

        attr_accessor :arr

        def initialize
                @arr = Array.new(10000000, 'TEST')
        end

end

while (true)
        b = Blah.new
        sleep 5
end

I noticed that the memory on my machine only goes up at the beginning
of the program, and then stays constant. I can only conclude that each
time the loop executes, the old b.arr becomes unreferenced and is
garbage collected and that the new b.arr is allocated (thus memory
usage is the same).

Correct again. You can view the effect with the script attached.

I just need someone to confirm this, since my program freezes after
running more than 24hours and I can't find the (memory) leakage.

You probably still hold on to more memory than you think.

Kind regards

robert

finalizer.rb (395 Bytes)

···

2007/10/9, Mr_Tibs <tiberiu.motoc@gmail.com>:

3

Thanks Robert.