在JSF saveState（）期间，线程在HashMap中停留在100％的CPU利用率 [英] Threads stuck at 100% CPU utilization in HashMap during JSF saveState()
问题描述
我们的生产环境存在问题，4个线程的HTOP命令处于100％CPU使用率。为了进一步研究这个问题，我生成了一个线程转储，以便找到正在吃CPU的线程。
We have an issue in our production environment, 4 Threads is at 100% CPU Usage from the HTOP command. To further investigate the issue I generated a Thread dump in order to find what thread is eating the CPU.
这是我发现的。 4个线程具有相同的堆栈跟踪，所有这些都处于 RUNNABLE 状态。不幸的是，我陷入了调查，因为堆栈跟踪没有引用我的内部代码，它更多地在Richfaces方面。我认为这是JSF呈现页面的部分。
Here is what i found out. The 4 threads has the same stack trace all of which are in RUNNABLE state. Unfortunately I am stuck at my investigation since the stack trace has no reference to my internal code it is more on Richfaces side. I think it is the part where JSF render a page.
堆栈跟踪。
"ajp-0.0.0.0-8009-47" daemon prio=10 tid=0x00007fb8040af000 nid=0x172c runnable [0x00007fb8b3bf8000]
java.lang.Thread.State: RUNNABLE
at java.util.HashMap.hash(HashMap.java:351)
at java.util.HashMap.putForCreate(HashMap.java:512)
at java.util.HashMap.putAllForCreate(HashMap.java:534)
at java.util.HashMap.<init>(HashMap.java:320)
at org.ajax4jsf.component.UIDataAdaptorBase.createChildStateCopy(UIDataAdaptorBase.java:894)
at org.ajax4jsf.component.UIDataAdaptorBase.saveState(UIDataAdaptorBase.java:1554)
at org.richfaces.component.UIDataTable.saveState(UIDataTable.java:181)
at org.richfaces.component.html.HtmlDataTable.saveState(HtmlDataTable.java:1361)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1103)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1119)
at org.ajax4jsf.component.AjaxViewRoot.processSaveState(AjaxViewRoot.java:751)
at org.ajax4jsf.application.AjaxStateManager.getComponentStateToSave(AjaxStateManager.java:179)
at org.ajax4jsf.application.AjaxStateManager.buildViewState(AjaxStateManager.java:515)
at org.ajax4jsf.application.AjaxStateManager$SeamStateManagerWrapper.saveView(AjaxStateManager.java:106)
at org.jboss.seam.jsf.SeamStateManager.saveView(SeamStateManager.java:89)
at org.ajax4jsf.application.AjaxStateManager.saveSerializedView(AjaxStateManager.java:470)
at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:615)
at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:110)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.josso.servlet.agent.GenericServletSSOAgentFilter.doFilter(GenericServletSSOAgentFilter.java:558)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:73)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:73)
at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:436)
at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:384)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:722)
另一件事是，有没有办法可以进入堆栈跟踪，让我说我想生成一个日志，以便我可以告诉我的应用程序中哪个页面正在生成这个堆栈跟踪？或者也许我可以使用阶段监听器？
Another thing is, Is there any way i can tap into the stack trace, lets say i wanted to generate a logs so that i can tell which page in my application this stack trace is being generated? Or maybe I can use a phase listener?
任何帮助都将不胜感激。
谢谢。
Any help would be appreciated. Thank you.
我使用的是Seam 2.2，Richfaces 3.3.3 final，JSF 1.2。
I am using Seam 2.2, Richfaces 3.3.3 final, JSF 1.2.
推荐答案
这，
java.lang.Thread.State: RUNNABLE
at java.util.HashMap.hash(HashMap.java:351)
at java.util.HashMap.putForCreate(HashMap.java:512)
at java.util.HashMap.putAllForCreate(HashMap.java:534)
at java.util.HashMap.<init>(HashMap.java:320)
这个，
java.lang.Thread.State: RUNNABLE
at java.util.HashMap.getEntry(HashMap.java:446)
at java.util.HashMap.get(HashMap.java:405)
当一个线程调用<时， java.util.HashMap 是已知的线程安全问题code> get（）而另一个线程同时执行 put（）。线程将在计算哈希期间陷入无限循环。此问题的技术解决方案是使用 ConcurrentMap 实现。另见a.o. 此dzone文章。
are known threadsafety problems with java.util.HashMap when one thread invokes a get() while another thread does at the same time a put(). The thread will during calculating the hash then stuck in an infinite loop . The technical solution to this problem is using a ConcurrentMap implementation instead. See also a.o. this dzone article.
但是，在您的具体情况下，
However, in your specific case,
at java.util.HashMap.<init>(HashMap.java:320)
at org.ajax4jsf.component.UIDataAdaptorBase.createChildStateCopy(UIDataAdaptorBase.java:894)
at org.ajax4jsf.component.UIDataAdaptorBase.saveState(UIDataAdaptorBase.java:1554)
at org.richfaces.component.UIDataTable.saveState(UIDataTable.java:181)
at org.richfaces.component.html.HtmlDataTable.saveState(HtmlDataTable.java:1361)
at javax.faces.component.UIComponentBase.processSaveState(UIComponentBase.java:1103)
当你的<$状态出现时，这个问题似乎会出现c $ c>< rich：dataTable> 组件即将保存。这反过来表明多个线程正在访问组件的同一个实例。这是不对的， UIComponent 类首先从未设计为线程安全。这反过来表明所讨论的组件实例不是JSF规范要求的请求范围。例如，当您使用 binding 将组件绑定到作用域或可能甚至是应用程序范围的bean，或者更糟的是静态字段时，就会发生这种情况。
this problem appears to manifest when the state of your <rich:dataTable> component is about to be saved. This in turn suggests that the very same instance of the component is being accessed by multiple threads. This is not right, the UIComponent class is in first place never designed to be threadsafe. This in turn indicates that the component instance in question is not request scoped as required by the JSF specification. This can for example happen when you're using binding to bind the component to a session scoped or perhaps even an application scoped bean or, worse, a static field.
<x:someComponent ... binding="#{nonRequestScopedBean.someComponent}">
您应该在代码库中寻找这样的组件并通过确保bean是相应的来修复它请求作用域，或者使用不同的解决方案来解决您认为使用绑定的需求/问题，这种方式将是正确的解决方案。
You should in your codebase look for such a component and fix it accordingly by making sure that the bean is request scoped, or by using a different solution for the requirement/problem for which you thought that using binding this way would be the right solution.
- How does the 'binding' attribute work in JSF? When and how should it be used?
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