XMLGrammarLoader memory leaks?

[Chris Simmons <cp...@decisionsoft.com>]

Hi,

I've been trying to track down memory leaks in our application and have 
noticed that the XMLGrammarLoader internally retains hard references to 
schema grammars after completing a parse.  This occurs in the grammar 
bucket and XSDHandler also keeps an import map, there may be other 
places too.  It does remove them on the next parse, but this kind of 
thing tends to obscure real leaks.  Discarding the parser is an option 
but it isn't ideal as it seems to involve quite a performance overhead 
compared with reusing the same parser.

I've also found that XSDHandler also has a field 'fParent' which appears 
to be a stack of  XSObject's.  This is never cleared, only grown as 
required, which means that an object that finds its way into here may 
well never be garbage collected.

Thanks,

Chris Simmons.


---------------------------------------------------------------------
To unsubscribe, e-mail: j-users-unsubscribe@xerces.apache.org
For additional commands, e-mail: j-users-help@xerces.apache.org

Re: XMLGrammarLoader memory leaks?

[Michael Glavassevich <mr...@ca.ibm.com>]

Hi Chris,

Chris Simmons <cp...@decisionsoft.com> wrote on 02/05/2007 09:00:04 AM:

> Hi,
> 
> I've been trying to track down memory leaks in our application and have 
> noticed that the XMLGrammarLoader internally retains hard references to 
> schema grammars after completing a parse.  This occurs in the grammar 
> bucket and XSDHandler also keeps an import map, there may be other 
> places too.  It does remove them on the next parse, but this kind of 
> thing tends to obscure real leaks.  Discarding the parser is an option 
> but it isn't ideal as it seems to involve quite a performance overhead 
> compared with reusing the same parser.

There are many more instances than that and probably hundreds of 
structures across the parser components which get cleared on reset or grow 
(e.g. the SymbolTable) as they're used. I understand that this makes it 
tough to monitor the memory usage but these aren't memory leaks [1].

> I've also found that XSDHandler also has a field 'fParent' which appears 

> to be a stack of  XSObject's.  This is never cleared, only grown as 
> required, which means that an object that finds its way into here may 
> well never be garbage collected.

Yeah, we should probably be clearing that.

> Thanks,
> 
> Chris Simmons.
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: j-users-unsubscribe@xerces.apache.org
> For additional commands, e-mail: j-users-help@xerces.apache.org

[1] http://en.wikipedia.org/wiki/Memory_leak#Is_it_a_memory_leak.3F

Michael Glavassevich
XML Parser Development
IBM Toronto Lab
E-mail: mrglavas@ca.ibm.com
E-mail: mrglavas@apache.org

---------------------------------------------------------------------
To unsubscribe, e-mail: j-users-unsubscribe@xerces.apache.org
For additional commands, e-mail: j-users-help@xerces.apache.org