From: brabuhr@...
Date: 2010-01-16T05:52:29+09:00
Subject: Re: WIN32OLE memory leaks

Jan 13, 2010, Chuck Remes:
> Jan 12, 2010, Luis Lavena:
>> Jan 12, 2010, Chuck Remes:
>>> In my ruby code I am making a call out to a COM object that is
>>> returning an array of objects. I extract some information from these
>>> objects and then request a new batch to do the same work all over again.
>>>
>>> Even though I am clearing the received array out, my program slowly
>>> leaks memory until it hits its limit (around 1.4 GB on Windows) and
>>> dies.
>>
>> Also, if this can be reproducible with any COM object, include a
>> sample script for us to reproduce in other Windows version and Ruby
>> version combinations.
>
> Here's some code. This is running against 1.8.6-p383 (from
> rubyinstaller.org) on Windows XP SP3 plus all the latest patches (Windows
> Update runs weekly).
>
> ...
>
> I have a method that makes a function call on the COM object
> (#request_data). When the function has data to return, it generates a
> "DataResolved" event which triggers my callback which was registered once at
> the beginning of execution. The callback calls #save and loops through the
> collection and pulls some properties into a hash which then gets inserted
> into mongodb. When the collection is exhausted, I go back to #request_data
> and make another call on the COM object to request the next batch.
>
> The collection returned is usually around 30MB. I don't leak all 30MB each
> time through; it leaks a big percentage of it though (30 to 50%).
>
> When Task Manager tells me the ruby.exe process is taking up around 1.4GB,
> the process just exits.
>
> Unfortunately this application is not available to the general public so I
> can't provide a script for someone to independently verify this. :(

I've never used it but "a simple memory leak detector for ruby":
http://codeforpeople.com/lib/ruby/dike/dike-0.0.4/README

Or, maybe roll your own:

def object_count
  count = Hash.new(0)
  ObjectSpace.each_object{|o| count[o.class] += 1}
  count
end

require 'pp'

loop {
  do_stuff
  pp object_count
}