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From Ugo Cei <u....@cbim.it>
Subject Re: Continuations and memory leaks
Date Wed, 11 Feb 2004 15:19:34 GMT
Christopher Oliver wrote:
> Ugo Cei wrote:
>> I'm experiencing a memory leak in an application we are currently 
>> testing, which uses Flowscript and Woody. Since continuations store a 
>> reference to local variables, and the memory leak does not manifest 
>> itself if I don't create any continuation, I'm starting to suspect 
>> that my usage of form.showForm is causing the leak.
>>
> What objects are leaked? Did you use Optimizeit or JProfiler to 
> determine this? What does your script look like?

All sorts of objects. My application uses Hibernate to persist objects 
and retrieve them for editing in a Woody form. Those objects in turn 
contain references to other persistent and/or transient objects or 
collections of the same. Some of those references are really to dynamic 
proxies, since Hibernate uses dynamic proxies for lazy loading.

I am using Optimizeit and it shows lots of objects that are never 
garbage-collected. The chains of references leading to these objects are 
rather complex and make debugging the real case very difficult. I will 
try to prepare a simpler testcase.

>> If this is indeed the case, how can I make sure that references to 
>> local variables will be properly nulled so that they can be garbage 
>> collected? Do they get forgotten when a continuation expires? 
> Yes.
>> And what if I invalidate the continuation
> Yes.

Hmmm, from my tests, it looks like doing:

var k = form.showForm(...);
k.invalidate();

does not make any difference. But I seem to recall that showForm() 
creates not one but *two* continuations, so maybe I need to invalidate 
also the one that is not returned by the function, but how?

I also waited about 10 minutes to see if the expiration of continuations 
  could allow the GC to reclaim some objects, but this did not seem to 
be the case too.

	Thank you,

		Ugo


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