Thanks.
I'll try Jconsole.
mas
On 05/04/2010 12:28 PM, Pid wrote:
> On 04/05/2010 14:10, Mark Shifman wrote:
>>
>> On 05/03/2010 02:53 PM, Pid wrote:
>>> On 03/05/2010 18:30, Mark Shifman wrote:
>>>>
>>>> On 05/03/2010 12:48 PM, Pid wrote:
>>>>> On 03/05/2010 17:15, Mark Shifman wrote:
>>>>>> I have a web app running under tomcat-6.0.26 with JreMemoryLeakPreventionListener,
java jdk1.6.0_18.
>>>>>>
>>>>>> Using jmap -histo pid, I can watch com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl,
etc increase in number
>>>>>> after running my unmarshal action, followed by undeploy and redeploy.
Find Leaks in the manager also finds leaks.
>>>
>>> Do you see log messages referring to potential leaks in the catalina.out
>>> log (assuming you're on a unix variant)?
>>>
>>> If so, can you post them please?
>>
>> There are no messages in catalia.out concerning leaks (I am using Linux 2.6.18-92.1.22.el5)
>> I also got rid of timeBetweenEvictionRunsMillis in datasource since it causes a leaky
TimerThread).
>>
>>>
>>> What does the manager 'find leaks' command report exactly?
>> ...
>> leak (use a profiler to confirm):
>> /yp_results
>
> There are some useful commands in the JDK which may help track down
> exactly which class is causing the problem.
>
> jmap -histo <pid>
>
> (and other jmap subcommands)
>
> If you take a snapshot periodically, esp after reload cycles you may be
> able to see which classes are increasing in number.
>
>
> If you can get a VisualVM working, or connect a JConsole to the remote
> VM you may be able to poke around and see which classes aren't being
> garbage collected.
>
>
>> My webapp is named yp_results.
>>>
>>>>> After a few undeploy/redeploy cycles does the number of
>>>>> WebappClassLoader's also increase?
>>>>
>>>> Yes it increases 1 for each undeploy/redeploy cycle.
>>>
>>>> snip... <
>>>
>>>>> Maybe.
>>>>>
>>>>>> JAXBContext.newInstance() can take a ClassLoader argument. Is there
some ClassLoader I should be using that will get around this?
>>>
>>> OK, so I've looked at JAXBContext (and JAXBContextImpl) and it doesn't
>>> (after quick read through) look like it's storing the classloader
>>> argument anywhere during the newInstance call, which is the usual source
>>> of leaks.
>
>
>>>>> Where is the jar with the above code, in a webapp?
>>>> The code above in in the war for the web app in a class in WEB-INF/classes/org/blablabla
>>>>
>>>> It is called via a class that looks like this:
>>>>
>>>> public class JAXBMascot {
>>>> protected static Log log = LogFactory.getLog(JAXBMascot.class);
>>>> private XMLEventReader reader;
>>>> private Unmarshaller u = JAXBContextMascot.INSTANCE.createUnmarshaller();
>>>
>>> You're setting the XMLEventReader, Unmarshaller & InputStream as
>>> instance field values, rather than completing the parsing in the
>>> getInstance() method?
>> I have really big xmls to unmarshall so I am using streaming them in and unmarshalling
the elements I want
>> and then insert into my database. I need the reader to see where I am and then the
umarshaller
>
> I'll have a look at the code below a bit later, am pushed for time right
> now.
>
>
> p
>
>
>
>> I didn't show the all the methods of JAXBMascot but here is workhorse:
>> public <T> T getNextElement(String theElement, String elementAfter, Class
<T>clazz) {
>> String elname = "";
>> T h = null;
>> try {
>> while(reader.hasNext()){
>> if(reader.peek().isStartElement()){
>> elname = reader.peek().asStartElement().getName().getLocalPart();
>> if(elname.equals(theElement)){
>> h= u.unmarshal(reader, clazz).getValue();
>> return h;
>> }
>> } else if(reader.peek().isEndElement()){
>> elname = reader.peek().asEndElement().getName().getLocalPart();
>> if(elname.equals(elementAfter)){
>> return h;
>> }
>> }
>>
>> reader.nextEvent();
>> }
>> } catch (XMLStreamException e) {
>> throw new RuntimeException(e);
>> } catch (JAXBException e) {
>> throw new RuntimeException(e);
>> }
>> return h;
>> }
>>
>> It also has a close method to clean up after I have gotten all the elements.
>> public void close(){
>> try {
>> reader.close();
>> } catch (XMLStreamException e) {
>> //quietly
>> }
>> IOUtils.closeQuietly(jxb_in);
>> u=null;
>> }
>> I don't think I am leaving any stuff hanging around but memory leaks are very sneaky.
>> mas
>>>
>>> This looks a bit odd to me, but I don't know what the rest of the
>>> instance does...
>>>
>>>
>>> p
>>>
>>>> private InputStream jxb_in;
>>>>
>>>> public static JAXBMascot getInstance(InputStream in) {
>>>> JAXBMascot m = new JAXBMascot();
>>>> try {
>>>> m.setJxb_in(in);
>>>> m.setReader(XMLInputFactory.newInstance().createXMLEventReader(in));
>>>> } catch (Exception e) {
>>>> log.fatal("error getting JAXBMascot instance");
>>>> IOUtils.closeQuietly(in);
>>>> throw new RuntimeException(e);
>>>> }
>>>>
>>>> return m;
>>>> }
>>>> ....
>>>> }
>>>>
>>>> This is also in the webapp in WEB-INF/classes/org/blablabla
>>>
>>>
>>>
>>
>
>
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