GuavaCache expireAfterWrite（）导致太多被阻塞的线程

时间：2017-04-05 05:02:48

标签： java multithreading guava contention

我们有一个用例，我们的数据在一段时间后变得陈旧。因此我们选择了expireAfterWrite缓存驱逐策略。但是这会导致线程池中阻塞的线程太多。知道为什么会发生这种情况，以及是否有办法避免这种情况。

示例线程池日志：

Debugger attached successfully.
Server compiler detected.
JVM version is 25.112-b15
Deadlock Detection:

No deadlocks found.

Thread 7546: (state = BLOCKED)
 - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information may be imprecise)
 - java.util.concurrent.locks.LockSupport.parkNanos(java.lang.Object, long) @bci=20, line=215 (Compiled frame)
 - java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(java.util.concurrent.SynchronousQueue$TransferStack$SNode, boolean, long) @bci=160, line=460 (Compiled frame)
 - java.util.concurrent.SynchronousQueue$TransferStack.transfer(java.lang.Object, boolean, long) @bci=102, line=362 (Compiled frame)
 - java.util.concurrent.SynchronousQueue.poll(long, java.util.concurrent.TimeUnit) @bci=11, line=941 (Compiled frame)
 - java.util.concurrent.ThreadPoolExecutor.getTask() @bci=134, line=1066 (Compiled frame)
 - java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=26, line=1127 (Compiled frame)
 - java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=5, line=617 (Compiled frame)
 - java.lang.Thread.run() @bci=11, line=745 (Compiled frame)

Locked ownable synchronizers:
    - None

Thread 1268: (state = BLOCKED)
 - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information may be imprecise)
 - java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=14, line=175 (Interpreted frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt() @bci=1, line=836 (Interpreted frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(int) @bci=72, line=997 (Interpreted frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(int) @bci=24, line=1304 (Compiled frame)
 - com.amazon.coral.google.common.util.concurrent.AbstractFuture$Sync.get() @bci=2 (Compiled frame)
 - com.amazon.coral.google.common.util.concurrent.AbstractFuture.get() @bci=4 (Compiled frame)
 - com.amazon.coral.google.common.util.concurrent.Uninterruptibles.getUninterruptibly(java.util.concurrent.Future) @bci=3 (Compiled frame)
 - com.amazon.coral.google.common.cache.LocalCache$LoadingValueReference.waitForValue() @bci=4 (Interpreted frame)
 - com.amazon.coral.google.common.cache.LocalCache$Segment.waitForLoadingValue(com.amazon.coral.google.common.cache.LocalCache$ReferenceEntry, java.lang.Object, com.amazon.coral.google.common.cache.LocalCache$ValueReference) @bci=44 (Interpreted frame)
 - com.amazon.coral.google.common.cache.LocalCache$Segment.get(java.lang.Object, int, com.amazon.coral.google.common.cache.CacheLoader) @bci=122 (Interpreted frame)
 - com.amazon.coral.google.common.cache.LocalCache.get(java.lang.Object, com.amazon.coral.google.common.cache.CacheLoader) @bci=17 (Compiled frame)
 - com.amazon.coral.google.common.cache.LocalCache.getOrLoad(java.lang.Object) @bci=6 (Compiled frame)
 - com.amazon.coral.google.common.cache.LocalCache$LocalLoadingCache.get(java.lang.Object) @bci=5 (Compiled frame)
 - com.amazon.csapp.services.SmartVideoCacheService.getVideos(com.amazon.csapp.utils.MetricsContext, com.amazon.csapp.utils.AmazonRequestInfo) @bci=33, line=214 (Compiled frame)
 - com.amazon.csapp.rest.resource.v2.VideoResource.getVideos(java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String) @bci=67, line=56 (Interpreted frame)
 - sun.reflect.GeneratedMethodAccessor90.invoke(java.lang.Object, java.lang.Object[]) @bci=88 (Compiled frame)
 - sun.reflect.DelegatingMethodAccessorImpl.invoke(java.lang.Object, java.lang.Object[]) @bci=6, line=43 (Compiled frame)
 - java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) @bci=56, line=498 (Compiled frame)
 - org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]) @bci=3, line=81 (Interpreted frame)
 - org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(java.lang.Object, java.lang.Object[]) @bci=39, line=128 (Interpreted frame)
 - org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(java.lang.Object, javax.ws.rs.core.Request) @bci=6, line=195 (Interpreted frame)
 - org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(java.lang.Object, org.glassfish.jersey.server.ContainerRequest) @bci=3, line=94 (Compiled frame)
 - org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(org.glassfish.jersey.server.ContainerRequest, java.lang.Object) @bci=13, line=353 (Compiled frame)
 - org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(org.glassfish.jersey.server.ContainerRequest) @bci=103, line=343 (Interpreted frame)
 - org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(java.lang.Object) @bci=5, line=102 (Interpreted frame)
 - org.glassfish.jersey.server.ServerRuntime$1.run() @bci=198, line=237 (Compiled frame)
 - org.glassfish.jersey.internal.Errors$1.call() @bci=4, line=271 (Compiled frame)
 - org.glassfish.jersey.internal.Errors$1.call() @bci=1, line=267 (Compiled frame)
 - org.glassfish.jersey.internal.Errors.process(java.util.concurrent.Callable, boolean) @bci=36, line=315 (Compiled frame)
 - org.glassfish.jersey.internal.Errors.process(org.glassfish.jersey.internal.util.Producer, boolean) @bci=2, line=297 (Compiled frame)
 - org.glassfish.jersey.internal.Errors.process(java.lang.Runnable) @bci=9, line=267 (Compiled frame)
 - org.glassfish.jersey.process.internal.RequestScope.runInScope(java.lang.Runnable) @bci=25, line=322 (Interpreted frame)
 - org.glassfish.jersey.server.ServerRuntime.process(org.glassfish.jersey.server.ContainerRequest) @bci=22, line=211 (Interpreted frame)
 - org.glassfish.jersey.server.ApplicationHandler.handle(org.glassfish.jersey.server.ContainerRequest) @bci=5, line=979 (Compiled frame)
 - org.glassfish.jersey.servlet.WebComponent.service(java.net.URI, java.net.URI, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) @bci=115, line=344 (Compiled frame)
 - org.glassfish.jersey.servlet.ServletContainer.service(java.net.URI, java.net.URI, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) @bci=9, line=372 (Compiled frame)
 - org.glassfish.jersey.servlet.ServletContainer.service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) @bci=321, line=335 (Compiled frame)
 - com.amazon.csapp.servlet.JerseyServletContainer.service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) @bci=15, line=26 (Compiled frame)
 - org.glassfish.jersey.servlet.ServletContainer.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse) @bci=39, line=218 (Compiled frame)
 - org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse) @bci=376, line=290 (Compiled frame)
 - org.apache.catalina.core.ApplicationFilterChain.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse) @bci=101, line=206 (Compiled frame)
 - org.apache.catalina.core.StandardWrapperValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=804, line=233 (Compiled frame)
 - org.apache.catalina.core.StandardContextValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=365, line=191 (Compiled frame)
 - org.apache.catalina.authenticator.AuthenticatorBase.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=327, line=470 (Compiled frame)
 - org.apache.catalina.core.StandardHostValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=64, line=127 (Compiled frame)
 - org.apache.catalina.valves.ErrorReportValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=6, line=103 (Compiled frame)
 - com.amazon.tomcat.valves.QueryLogValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=47, line=78 (Compiled frame)
 - org.apache.catalina.valves.AccessLogValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=24, line=617 (Compiled frame)
 - org.apache.catalina.core.StandardEngineValve.invoke(org.apache.catalina.connector.Request, org.apache.catalina.connector.Response) @bci=42, line=109 (Compiled frame)
 - org.apache.catalina.connector.CoyoteAdapter.service(org.apache.coyote.Request, org.apache.coyote.Response) @bci=158, line=293 (Compiled frame)
 - org.apache.coyote.http11.Http11Processor.process(java.net.Socket) @bci=545, line=859 (Compiled frame)
 - org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(java.net.Socket) @bci=73, line=610 (Compiled frame)
 - org.apache.tomcat.util.net.JIoEndpoint$Worker.run() @bci=41, line=503 (Compiled frame)
 - java.lang.Thread.run() @bci=11, line=745 (Compiled frame)

1 个答案:

答案 0 :(得分：0)

您应该更频繁地将dedicated thread添加到refresh缓存的值。正如Ben Manes建议的那样，配置低于到期阈值的refreshAfterWrite也会有所帮助，但是您要覆盖reload()以异步方式完成工作。

您的代码中也可能存在热点，导致许多单独的路径尝试同时访问相同的缓存键。如果您不期望这种行为（例如，您希望一次大约有一个线程可以访问密钥），您可能需要调查是否存在一些缺少锁定语义导致太多线程无法读取同时缓存，或者不同的热点原因，例如异常请求模式。

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