[jboss-dev-forums] [JBoss AS Development] - Performance issue: VFSClassLoaderPolicy uses URL.hashCode(),

ttarhan do-not-reply at jboss.com
Tue Sep 15 23:20:26 EDT 2009 

I believe I have found a performance issue in JBoss AS 5.1.0.GA caused by the use of a ConcurrentHashMap with URL objects as the hash key. The offending usage is in VFSClassLoaderPolicy, in a member field named manifestCache. The field manifestCache is initialized as ConcurrentHashMap<URL, Manifest>();

The underlying issue is that URL.hashCode() is a non-trivial operation, often requiring a DNS lookup. This DNS lookup can take a long time to timeout, adding up to 1-minute to the startup time of the application server .The issue is also encountered during runtime if certain class loader features are used (ie. getResource), causing up to a 1-minute delay when such features are used.

The DNS lookups will never resolve in most cases, as the URL objects in question are usually in the form of:

vfsmemory:aa15-xok7cr-fznfpulr-1-fznfpxto-7...

A simple fix is to use the String returned form URL.toString() as the map key.

Can anyone confirm that this in in fact a bug? The delays can be a significant issue, especially the runtime delays.

Backtrace showing URL.hashCode causing a DNS lookup when used in ConcurrentHashMap from VFSClassLoaderPolicy:

  | 	Inet6AddressImpl.lookupAllHostAddr(String) line: not available [native method]	
  | 	InetAddress$1.lookupAllHostAddr(String) line: 849	
  | 	InetAddress.getAddressFromNameService(String, InetAddress) line: 1200	
  | 	InetAddress.getAllByName0(String, InetAddress, boolean) line: 1153	
  | 	InetAddress.getAllByName(String, InetAddress) line: 1083	
  | 	InetAddress.getAllByName(String) line: 1019	
  | 	InetAddress.getByName(String) line: 969	
  | 	Handler(URLStreamHandler).getHostAddress(URL) line: 420	
  | 	Handler(URLStreamHandler).hashCode(URL) line: 337	
  | 	URL.hashCode() line: 857 [local variables unavailable]	
  | 	ConcurrentHashMap<K,V>.get(Object) line: 768	
  | 	VFSClassLoaderPolicy.getClassPackageInformation(String, String) line: 606	
  | 	BaseClassLoader.definePackage(String, URL) line: 722	
  | 	BaseClassLoader$2.run() line: 567	
  | 	BaseClassLoader$2.run() line: 532	
  | 	AccessController.doPrivileged(PrivilegedAction<T>, AccessControlContext) line: not available [native method]	
  | 	BaseClassLoader.loadClassLocally(String, boolean) line: 530	
  | 	BaseClassLoader.loadClassLocally(String) line: 507	
  | 	DelegateLoader(BaseDelegateLoader).loadClass(String) line: 134	
  | 	ClassLoadingTask$ThreadTask.run() line: 452	
  | 	ClassLoaderManager.nextTask(Thread, ClassLoadingTask) line: 251	
  | 	ClassLoaderManager.process(Thread, ClassLoadingTask) line: 150	
  | 	ClassLoaderDomain(BaseClassLoaderDomain).loadClass(BaseClassLoader, String, boolean) line: 265	
  | 	ClassLoaderDomain(BaseClassLoaderDomain).loadClass(BaseClassLoader, String) line: 1119	
  | 	BaseClassLoader.loadClassFromDomain(String, boolean) line: 798	
  | 	BaseClassLoader.loadClass(String, boolean) line: 441	
  | 	BaseClassLoader(ClassLoader).loadClass(String) line: 252	
  | 	ToClassInvoker.toClass(ToClassInvokerPoolReference, CtClass, String, ClassLoader, ProtectionDomain) line: 88	
  | 	JBossClDelegatingClassPool.toClass(CtClass, ClassLoader, ProtectionDomain) line: 81	
  | 	CtNewClass(CtClass).toClass(ClassLoader, ProtectionDomain) line: 1094	
  | 	TransformerCommon$ToClassAction$2.toClass(CtClass, ClassLoader, ProtectionDomain) line: 331	
  | 	TransformerCommon.toClass(CtClass, ClassLoader, ProtectionDomain) line: 139	
  | 	ProxyFactory.createProxyClass(ClassLoader, ProxyMixin[], Class<?>[]) line: 126	
  | 	ProxyFactory.createInterfaceProxy(GUID, ClassLoader, Class<?>[], ProxyMixin[], InstanceAdvisor) line: 96	
  | 	ProxyFactory.createInterfaceProxy(GUID, ClassLoader, Class<?>[]) line: 86	
  | 	Remoting.createRemoteProxy(Object, ClassLoader, Class[], InvokerLocator, List<Interceptor>, String) line: 102	
  | 	ManagedOperationProxyFactory.createDispatcherProxy() line: 203	
  | 	ManagedOperationProxyFactory.start() line: 109	
  | 	NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
  | 	NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39	
  | 	DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25	
  | 	Method.invoke(Object, Object...) line: 597	
  | 	ReflectionUtils.invoke(Method, Object, Object[]) line: 59	
  | 	ReflectMethodInfoImpl.invoke(Object, Object[]) line: 150	
  | 	BasicMethodJoinPoint.dispatch() line: 66	
  | 	KernelControllerContextAction$JoinpointDispatchWrapper.execute() line: 241	
  | 	KernelControllerContextAction$JoinpointDispatchWrapper(ExecutionWrapper).execute(AccessControlContext) line: 47	
  | 	KernelControllerContextAction.dispatchExecutionWrapper(KernelControllerContext, ExecutionWrapper) line: 109	
  | 	KernelControllerContextAction.dispatchJoinPoint(KernelControllerContext, Joinpoint) line: 70	
  | 	StartStopLifecycleAction(LifecycleAction).installActionInternal(KernelControllerContext) line: 221	
  | 	StartStopLifecycleAction(InstallsAwareAction).installAction(KernelControllerContext) line: 54	
  | 	StartStopLifecycleAction(InstallsAwareAction).installAction(ControllerContext) line: 42	
  | 	StartStopLifecycleAction(SimpleControllerContextAction<T>).simpleInstallAction(T) line: 62	
  | 	StartStopLifecycleAction(AccessControllerContextAction<S,T>).install(ControllerContext) line: 71	
  | 	KernelControllerContextActions(AbstractControllerContextActions).install(ControllerContext, ControllerState, ControllerState) line: 51	
  | 	AbstractKernelControllerContext(AbstractControllerContext).install(ControllerState, ControllerState) line: 348	
  | 	AbstractKernelController(AbstractController).install(ControllerContext, ControllerState, ControllerState) line: 1631	
  | 	AbstractKernelController(AbstractController).incrementState(ControllerContext, boolean) line: 934	
  | 	AbstractKernelController(AbstractController).resolveContexts(ControllerState, ControllerState, boolean) line: 1082	
  | 	AbstractKernelController(AbstractController).resolveContexts(boolean) line: 984	
  | 	AbstractKernelController(AbstractController).install(ControllerContext, boolean) line: 774	
  | 	AbstractKernelController(AbstractController).install(ControllerContext) line: 540	
  | 	ServiceController.doInstall(KernelController, ServiceControllerContext) line: 670	
  | 	ServiceController.register(ObjectName, Collection<ObjectName>, boolean, Object) line: 373	
  | 	ServiceControllerRegistrationLifecycleCallback.install(ControllerContext) line: 104	
  | 	NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
  | 	NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39	
  | 	DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25	
  | 	Method.invoke(Object, Object...) line: 597	
  | 	ReflectionUtils.invoke(Method, Object, Object[]) line: 59	
  | 	ReflectMethodInfoImpl.invoke(Object, Object[]) line: 150	
  | 	BasicMethodJoinPoint.dispatch() line: 66	
  | 	AbstractBeanInfo.invoke(Object, String, String[], Object[]) line: 300	
  | 	AbstractKernelControllerContext.invoke(String, Object[], String[]) line: 286	
  | 	AbstractLifecycleCallbackItem.install(ControllerContext) line: 87	
  | 	AbstractKernelController(AbstractController).handleLifecycleCallbacks(ControllerContext, ControllerState, boolean) line: 1568	
  | 	AbstractKernelController(AbstractController).handleInstallLifecycleCallbacks(ControllerContext, ControllerState) line: 1533	
  | 	AbstractKernelController(AbstractController).incrementState(ControllerContext, boolean) line: 943	
  | 	AbstractKernelController(AbstractController).resolveContexts(ControllerState, ControllerState, boolean) line: 1082	
  | 	AbstractKernelController(AbstractController).resolveContexts(boolean) line: 984	
  | 	AbstractKernelController(AbstractController).change(ControllerContext, ControllerState, boolean) line: 822	
  | 	AbstractKernelController(AbstractController).change(ControllerContext, ControllerState) line: 553	
  | 	ServiceController.doChange(KernelController, ServiceControllerContext, ControllerState, String) line: 688	
  | 	ServiceController.start(ObjectName) line: 460	
  | 	ServiceControllerStartStopLifecycleCallback.install(ControllerContext) line: 44	
  | 	NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
  | 	NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39	
  | 	DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25	
  | 	Method.invoke(Object, Object...) line: 597	
  | 	ReflectionUtils.invoke(Method, Object, Object[]) line: 59	
  | 	ReflectMethodInfoImpl.invoke(Object, Object[]) line: 150	
  | 	BasicMethodJoinPoint.dispatch() line: 66	
  | 	AbstractBeanInfo.invoke(Object, String, String[], Object[]) line: 300	
  | 	AbstractKernelControllerContext.invoke(String, Object[], String[]) line: 286	
  | 	AbstractLifecycleCallbackItem.install(ControllerContext) line: 87	
  | 	AbstractKernelController(AbstractController).handleLifecycleCallbacks(ControllerContext, ControllerState, boolean) line: 1568	
  | 	AbstractKernelController(AbstractController).handleInstallLifecycleCallbacks(ControllerContext, ControllerState) line: 1533	
  | 	AbstractKernelController(AbstractController).incrementState(ControllerContext, boolean) line: 943	
  | 	AbstractKernelController(AbstractController).resolveContexts(ControllerState, ControllerState, boolean) line: 1082	
  | 	AbstractKernelController(AbstractController).resolveContexts(boolean) line: 984	
  | 	AbstractKernelController(AbstractController).install(ControllerContext, boolean) line: 774	
  | 	AbstractKernelController(AbstractController).install(ControllerContext) line: 540	
  | 	BeanMetaDataDeployer.deploy(DeploymentUnit, BeanMetaData) line: 121	
  | 	BeanMetaDataDeployer.deploy(DeploymentUnit, Object) line: 51	
  | 	BeanMetaDataDeployer(AbstractSimpleRealDeployer<T>).internalDeploy(DeploymentUnit) line: 62	
  | 	BeanMetaDataDeployer(AbstractRealDeployer).deploy(DeploymentUnit) line: 50	
  | 	DeployerWrapper.deploy(DeploymentUnit) line: 171	
  | 	DeployersImpl.doDeploy(Deployer, DeploymentUnit) line: 1439	
  | 	DeployersImpl.doInstallParentFirst(Deployer, DeploymentContext) line: 1157	
  | 	DeployersImpl.doInstallParentFirst(Deployer, DeploymentContext) line: 1178	
  | 	DeployersImpl.install(ControllerContext, ControllerState, ControllerState) line: 1098	
  | 	DeploymentControllerContext(AbstractControllerContext).install(ControllerState, ControllerState) line: 348	
  | 	AbstractKernelController(AbstractController).install(ControllerContext, ControllerState, ControllerState) line: 1631	
  | 	AbstractKernelController(AbstractController).incrementState(ControllerContext, boolean) line: 934	
  | 	AbstractKernelController(AbstractController).resolveContexts(ControllerState, ControllerState, boolean) line: 1082	
  | 	AbstractKernelController(AbstractController).resolveContexts(boolean) line: 984	
  | 	AbstractKernelController(AbstractController).change(ControllerContext, ControllerState, boolean) line: 822	
  | 	AbstractKernelController(AbstractController).change(ControllerContext, ControllerState) line: 553	
  | 	DeployersImpl.process(List<DeploymentContext>, List<DeploymentContext>) line: 781	
  | 	MainDeployerImpl.process() line: 702	
  | 	MainDeployerAdapter.process() line: 117	
  | 	ProfileDeployAction.install(Profile) line: 70	
  | 	ProfileDeployAction(AbstractProfileAction).install(ProfileContext) line: 53	
  | 	AbstractProfileService.install(ControllerContext, ControllerState, ControllerState) line: 361	
  | 	ProfileContext(AbstractControllerContext).install(ControllerState, ControllerState) line: 348	
  | 	ScopedProfileServiceController(AbstractController).install(ControllerContext, ControllerState, ControllerState) line: 1631	
  | 	ScopedProfileServiceController(AbstractController).incrementState(ControllerContext, boolean) line: 934	
  | 	ScopedProfileServiceController(AbstractController).resolveContexts(ControllerState, ControllerState, boolean) line: 1082	
  | 	ScopedProfileServiceController(AbstractController).resolveContexts(boolean) line: 984	
  | 	ScopedProfileServiceController(AbstractController).change(ControllerContext, ControllerState, boolean) line: 822	
  | 	ScopedProfileServiceController(AbstractController).change(ControllerContext, ControllerState) line: 553	
  | 	AbstractProfileService.activateProfile(ProfileKey) line: 306	
  | 	ProfileServiceBootstrap.start(Server) line: 271	
  | 	ServerImpl(AbstractServerImpl).start() line: 461	
  | 	Main.boot(String[]) line: 221	
  | 	Main$1.run() line: 556	
  | 	Thread.run() line: 619	
  | 

View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4255422#4255422

Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=4255422

More information about the jboss-dev-forums mailing list