Re: possible memory leak issue in 1.2 dev (as of SVN:821662)

Ferenc,

The latest trunk shouldn't have memory problems with XPath queries.  
Unfortunately, it is slower now, too, as there were not many options  
for fixing the problem short of reimplementing DTMManager, so the  
patch is the solution you proposed.

Again, thank you for reporting the bug and providing fix for it.

Natalia

On Oct 23, 2009, at 5:04 PM, Ferenc Pápai wrote:

> Hi Natalia,
>
> I had the issue on 2 Vistas and 1 XP, all running Java 1.6.0_16
>
> Output on on Vista:
>
> C:\Users\feri>java -version
> java version "1.6.0_16"
> Java(TM) SE Runtime Environment (build 1.6.0_16-b01)
> Java HotSpot(TM) Client VM (build 14.2-b01, mixed mode, sharing)
>
>
> let me know how can I help more
> Ferenc
>
>
> On Fri, Oct 23, 2009 at 13:50, Natalia Shilenkova <[email protected] 
> > wrote:
> Ferenc,
>
> Thank you for reporting the problem. Could you please let me know what
> OS and JVM version you use to run Xindice (please include all the
> information "java -version" reports)?
>
> I'll investigate the problem.
>
> Regards,
> Natalia
>
> 2009/10/21 Ferenc Pápai <[email protected]>:
> >
> >
> > Hi
> >
> > I think I discovered a memory leak while an XPath query is  
> executed using
> > Xindice 1.2 dev svn revision number 821662.
> >
> > I only had to run a query that generated a sufficiently large  
> number of
> > results.
> >
> > After some debugging I discovered that in class  
> XPathQueryResolver.ResultSet
> > the XPathResolverContext member variable is cached now as opposed  
> to as it
> > was in its previous version.
> > This is probably for performance reasons.
> >
> > This class XPathResolverContext has internally a DTMManager  
> implementation.
> > As ResultSet.prepareNextNode method is called many times (while  
> one query is
> > executed),  the DTMManager instance will grow and grow in size  
> until JVM
> > runs out of memory.
> >
> > Calling XPathResolverContext .reset() in ResultSet.prepareNextNode  
> would
> > solve this problem but it would be against the intent of  
> optimizing the
> > code.
> >
> >
> > I am not familiar yet with Xalan's DTM API to provide a proper  
> solution. So
> > i am just speculating here:
> > Internally DTMManager caches DTM objects generated while it  
> executed the
> > query on a given context. These DTMs consume the memory.
> > I think these are cached to be reused by the two-way iterators  
> provided by
> > DTMManager.
> > However in Xindice, the Collection API provides the NodeSet as  
> forward only
> > iterator, thus no DTM caching is need for Xindice. ?
> >
> >
> > regards,
> > Ferenc
> >
> >
> >
> >
> >
> >
> >
> >
> >
>