SOAP::Lite leaking memory

Jonathan Stowe jns at
Thu Mar 15 12:58:22 GMT 2007

On Thu, 2007-03-15 at 12:02 +0000, Gareth Harper wrote:
> Jonathan Stowe wrote:
> >"going out of scope" is not necessarily going to cause everything to go
> >away as SOAP::Lite dynamically creates methods in a variety of
> >namespaces (I'm not going to check right now as the code makes me
> >uneasy) and it is possible that it is closing over some of the lexical
> >variables.
> >
> >  
> >
> It's going out of scope as far as any of the code I have written works 
> (there's nothing clever in my code, it's a very basic class), however 
> I'm fairly certain that SOAP::Lite is creating some things and caching them.

Yes it is, it creates a load of methods dynamically directly into
various namespaces under 'SOAP::Lite'. without examining the code or
more probably instrumenting it in some way I would suspect that these
subroutines are creating closures which are keeping otherwise lexical
variables alive.

> >If you are using the "autoloaded" interface (i.e.
> >$soap->YourMethod(@args) ) you might want to try the explicit call (i.e.
> >$soap->call('MyMethod', @args) ) as that is possibly going to fiddle
> >with the symbol table less.
> >
> >  
> >
> I'll check that out, but from what I was seeing in the results from 
> Devel::Leak a lot of the information in those variables is the actual 
> XML back and forth between my client and the server.  I've just 
> installed Devel::LeakTrace::Fast which supposedly lets me know which 
> line is allocating the variables.  if it's in the constructor I might 
> have to just bite the bullet and use a global.  I'd rather not have to 
> manually remove references to various objects internal to SOAP::Lite.
> >You might also want to test this with just re-using the single
> >SOAP::Lite object as I seem to recall that most of the horrible stuff
> >happens in the constructor.
> >  
> >
> I can try this, though I'd rather not, as the module I'm writing is to 
> be dynamically loaded as required by one of our systems (effectively 
> it's a turing engine, but it's a little more complex and specialised 
> than that) as required.  Making the module when loaded keep a global 
> around with a SOAP object in it is feasable but undesireable.  I did 
> troll through the SOAP::Lite documentation in the hope of a "don't cache 
> objects" option just in case but that didn't appear.  For testing 
> purposes I'll create a global and see if that prevents the memory leaks, 
> if it does at least it gives me a somewhat nicer alternative than 
> forking off a process every time this function gets called.

If you could provide us with an example of the code that you are testing
with then I'm sure we could move on from wild guesses to the real cause
- mocking up the server proxy is fairly trivial.


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