我正在使用App Engine（java）和MemCache。当我尝试我的代码时似乎一切正常。但是当我增加我的实例的负载时，我有时会得到以下堆栈跟踪。
com.google.api.server.spi.SystemService invokeServiceMethod: exception occurred while calling backend method
java.util.concurrent.ExecutionException: com.google.appengine.api.memcache.MemcacheServiceException: Unexpected failure
at java.util.concurrent.FutureTask.report(FutureTask.java:106)
at java.util.concurrent.FutureTask.get(FutureTask.java:186)
at com.peerke.outdoorpuzzlegame.backend.gameclientendpoint.data.GameDataMerger.mergeGameData(GameDataMerger.java:52)
at com.peerke.outdoorpuzzlegame.backend.gameclientendpoint.endpoints.ActiveGamesEndpoint.getMergedGameData(ActiveGamesEndpoint.java:236)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:44)
at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:363)
at com.google.api.server.spi.SystemServiceServlet.execute(SystemServiceServlet.java:113)
at com.google.api.server.spi.SystemServiceServlet.doPost(SystemServiceServlet.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:48)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.peerke.outdoorpuzzlegame.backend.common.gcp.NamespaceFilter.doFilter(NamespaceFilter.java:31)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:439)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:446)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:256)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:310)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:302)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:443)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.google.appengine.api.memcache.MemcacheServiceException: Unexpected failure
at com.google.appengine.api.memcache.MemcacheServiceImpl.quietGet(MemcacheServiceImpl.java:29)
at com.google.appengine.api.memcache.MemcacheServiceImpl.get(MemcacheServiceImpl.java:49)
at com.peerke.outdoorpuzzlegame.backend.common.datastore.DataManagerGame.getGame(DataManagerGame.java:39)
at com.peerke.outdoorpuzzlegame.backend.common.datastore.DataManagerGame.getGameFromActiveGame(DataManagerGame.java:21)
at com.peerke.outdoorpuzzlegame.backend.common.datastore.DataManagerGame$1.call(DataManagerGame.java:31)
at com.peerke.outdoorpuzzlegame.backend.common.datastore.DataManagerGame$1.call(DataManagerGame.java:28)
at com.peerke.outdoorpuzzlegame.backend.common.background.BackGroundTasks$ObjectifyCallable.call(BackGroundTasks.java:51)
at java.util.concurrent.FutureTask.run(FutureTask.java:260)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1168)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:605)
Caused by: java.lang.InterruptedException
at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:393)
at com.google.common.util.concurrent.AbstractFuture$TrustedFuture.get(AbstractFuture.java:90)
at com.google.appengine.tools.development.TimedFuture.get(TimedFuture.java:42)
at com.google.common.util.concurrent.ForwardingFuture.get(ForwardingFuture.java:63)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:89)
at com.google.appengine.api.memcache.MemcacheServiceImpl.quietGet(MemcacheServiceImpl.java:26)
... 9 more
当我查看堆栈跟踪时，我看到MemcacheService.get（...）方法被中断。但我不明白为什么。整个电话不到60秒的限制。
有人有任何想法吗？