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https://issues.apache.org/jira/browse/YARN-7266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16780186#comment-16780186
]
Eric Yang commented on YARN-7266:
---------------------------------
Volatile keyword means all read/write of the variable must be non-cached. It
is useful when read/update/write operation does not need to be atomic. Without
locking if statement, there might be concurrency problem that first thread is
updating the data structure for JaxbContext, and the second thread is given to
the same location of partially updated memory location, and attempt to read
from it. Threads that returned with partial updates may receive NPE.
When synchronized on condition, only the first thread will update jaxbContext
before other threads have a chance to enter, but other threads can use cached
value. Synchronized turn around time for checking a cache value is null, isn't
free but it is required for initialization. The stack trace seems to indicate
that wadl initialization is happening at the same time request is serving.
Wadl initialization and ContextResolver initialization are usually independent
thread from serving thread. This allows webapp server to speed up creation of
worker threads, and clone initialized settings to worker threads efficiently.
This doesn't appear to be the case for Timeline server. Maybe there is other
ways to break up the serving thread from Jersey initialization?
> Timeline Server event handler threads locked
> --------------------------------------------
>
> Key: YARN-7266
> URL: https://issues.apache.org/jira/browse/YARN-7266
> Project: Hadoop YARN
> Issue Type: Bug
> Components: ATSv2, timelineserver
> Affects Versions: 2.7.3
> Reporter: Venkata Puneet Ravuri
> Assignee: Prabhu Joseph
> Priority: Major
> Attachments: YARN-7266-0005.patch, YARN-7266-001.patch,
> YARN-7266-002.patch, YARN-7266-003.patch, YARN-7266-004.patch,
> YARN-7266-006.patch
>
>
> Event handlers for Timeline Server seem to take a lock while parsing HTTP
> headers of the request. This is causing all other threads to wait and slowing
> down the overall performance of Timeline server. We have resourcemanager
> metrics enabled to send to timeline server. Because of the high load on
> ResourceManager, the metrics to be sent are getting backlogged and in turn
> increasing heap footprint of Resource Manager (due to pending metrics).
> This is the complete stack trace of a blocked thread on timeline server:-
> "2079644967@qtp-1658980982-4560" #4632 daemon prio=5 os_prio=0
> tid=0x00007f6ba490a000 nid=0x5eb waiting for monitor entry
> [0x00007f6b9142c000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> com.sun.xml.bind.v2.runtime.reflect.opt.AccessorInjector.prepare(AccessorInjector.java:82)
> - waiting to lock <0x00000005c0621860> (a java.lang.Class for
> com.sun.xml.bind.v2.runtime.reflect.opt.AccessorInjector)
> at
> com.sun.xml.bind.v2.runtime.reflect.opt.OptimizedAccessorFactory.get(OptimizedAccessorFactory.java:168)
> at
> com.sun.xml.bind.v2.runtime.reflect.Accessor$FieldReflection.optimize(Accessor.java:282)
> at
> com.sun.xml.bind.v2.runtime.property.SingleElementNodeProperty.<init>(SingleElementNodeProperty.java:94)
> at sun.reflect.GeneratedConstructorAccessor52.newInstance(Unknown
> Source)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
> Source)
> at java.lang.reflect.Constructor.newInstance(Unknown Source)
> at
> com.sun.xml.bind.v2.runtime.property.PropertyFactory.create(PropertyFactory.java:128)
> at
> com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.<init>(ClassBeanInfoImpl.java:183)
> at
> com.sun.xml.bind.v2.runtime.JAXBContextImpl.getOrCreate(JAXBContextImpl.java:532)
> at
> com.sun.xml.bind.v2.runtime.JAXBContextImpl.getOrCreate(JAXBContextImpl.java:551)
> at
> com.sun.xml.bind.v2.runtime.property.ArrayElementProperty.<init>(ArrayElementProperty.java:112)
> at
> com.sun.xml.bind.v2.runtime.property.ArrayElementNodeProperty.<init>(ArrayElementNodeProperty.java:62)
> at sun.reflect.GeneratedConstructorAccessor19.newInstance(Unknown
> Source)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
> Source)
> at java.lang.reflect.Constructor.newInstance(Unknown Source)
> at
> com.sun.xml.bind.v2.runtime.property.PropertyFactory.create(PropertyFactory.java:128)
> at
> com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.<init>(ClassBeanInfoImpl.java:183)
> at
> com.sun.xml.bind.v2.runtime.JAXBContextImpl.getOrCreate(JAXBContextImpl.java:532)
> at
> com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:347)
> at
> com.sun.xml.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(JAXBContextImpl.java:1170)
> at
> com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:145)
> at sun.reflect.GeneratedMethodAccessor17.invoke(Unknown Source)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
> at java.lang.reflect.Method.invoke(Unknown Source)
> at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
> at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
> at javax.xml.bind.ContextFinder.find(Unknown Source)
> at javax.xml.bind.JAXBContext.newInstance(Unknown Source)
> at javax.xml.bind.JAXBContext.newInstance(Unknown Source)
> at
> com.sun.jersey.server.wadl.generators.WadlGeneratorJAXBGrammarGenerator.buildModelAndSchemas(WadlGeneratorJAXBGrammarGenerator.java:412)
> at
> com.sun.jersey.server.wadl.generators.WadlGeneratorJAXBGrammarGenerator.createExternalGrammar(WadlGeneratorJAXBGrammarGenerator.java:352)
> at
> com.sun.jersey.server.wadl.WadlBuilder.generate(WadlBuilder.java:115)
> at
> com.sun.jersey.server.impl.wadl.WadlApplicationContextImpl.getApplication(WadlApplicationContextImpl.java:104)
> at
> com.sun.jersey.server.impl.wadl.WadlApplicationContextImpl.getApplication(WadlApplicationContextImpl.java:120)
> at
> com.sun.jersey.server.impl.wadl.WadlMethodFactory$WadlOptionsMethodDispatcher.dispatch(WadlMethodFactory.java:98)
> at
> com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
> at
> com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
> at
> com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
> at
> com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
> at
> com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:886)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:834)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:795)
> at
> com.google.inject.servlet.FilterDefinition.doFilter(FilterDefinition.java:163)
> at
> com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:58)
> at
> com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:118)
> at
> com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:113)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.http.lib.StaticUserWebFilter$StaticUserFilter.doFilter(StaticUserWebFilter.java:96)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:594)
> at
> org.apache.hadoop.security.token.delegation.web.DelegationTokenAuthenticationFilter.doFilter(DelegationTokenAuthenticationFilter.java:291)
> at
> org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:553)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.security.http.CrossOriginFilter.doFilter(CrossOriginFilter.java:95)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.http.HttpServer2$QuotingInputFilter.doFilter(HttpServer2.java:1243)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
> at
> org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
> at
> org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
> at
> org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
> at
> org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
> at
> org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
> at
> org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
> at
> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
> at org.mortbay.jetty.Server.handle(Server.java:326)
> at
> org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
> at
> org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
> at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
> at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
> at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
> at
> org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
> at
> org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
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