我正在尝试处理超过20K行的大型Excel文件。每行应保存为数据存储区中的实体。首先，我使用Blobstore在我的servlet中获取excel文件，然后使用Task Queue服务对任务进行排队。此任务，读取excel文件，转换实体中的每一行并存储它。正如我之前所说，Excel文件可能有超过20K行。过了一会儿，我得到了这个例外：
com.xxx.xxx.ProcessBlob doPost: |POST|ProcessBlob|Exception:Task was cancelled.|Msg:Task was cancelled.|Stack:java.util.concurrent.CancellationException: Task was cancelled.
at com.google.common.util.concurrent.AbstractFuture.cancellationExceptionWithCause(AbstractFuture.java:796)
at com.google.common.util.concurrent.AbstractFuture.getDoneValue(AbstractFuture.java:475)
at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:381)
at com.google.common.util.concurrent.AbstractFuture$TrustedFuture.get(AbstractFuture.java:85)
at com.google.appengine.tools.development.TimedFuture.get(TimedFuture.java:42)
at com.google.common.util.concurrent.ForwardingFuture.get(ForwardingFuture.java:63)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
at com.google.appengine.api.datastore.Batcher$ReorderingMultiFuture.get(Batcher.java:131)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
at com.google.appengine.api.datastore.FutureHelper.getInternal(FutureHelper.java:75)
at com.google.appengine.api.datastore.FutureHelper.quietGet(FutureHelper.java:35)
at com.google.appengine.api.datastore.DatastoreServiceImpl.put(DatastoreServiceImpl.java:56)
at com.xxx.xxx.xxx.createEntity(EntityService.java:87)
at com.xxx.xxx.ProcessBlob.doPost(ProcessBlob.java:145)
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$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:254)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:146)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:527)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:437)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:444)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:308)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:300)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:441)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.util.concurrent.CancellationException: Future.cancel() was called.
at com.google.common.util.concurrent.AbstractFuture.cancel(AbstractFuture.java:514)
at com.google.appengine.tools.development.TimedFuture.cancel(TimedFuture.java:85)
at com.google.common.util.concurrent.ForwardingFuture.cancel(ForwardingFuture.java:48)
at com.google.apphosting.runtime.ApiProxyImpl$AsyncApiFuture.cancel(ApiProxyImpl.java:553)
at com.google.apphosting.runtime.RequestManager.cancelPendingAsyncFutures(RequestManager.java:626)
at com.google.apphosting.runtime.RequestManager.sendDeadline(RequestManager.java:399)
at com.google.apphosting.runtime.RequestManager.sendDeadline(RequestManager.java:357)
at com.google.apphosting.runtime.CloneControllerImpl.sendDeadline(CloneControllerImpl.java:201)
at com.google.apphosting.sandbox.ModelClonePb$CloneController$ServiceParameters$3.handleRequest(ModelClonePb.java:1166)
at com.google.net.rpc3.impl.server.RpcServerInternalContext.runRpcInApplication(RpcServerInternalContext.java:558)
at com.google.net.rpc3.impl.server.RpcServerChannel$1.run(RpcServerChannel.java:871)
at com.google.tracing.LocalTraceSpanRunnable.run(LocalTraceSpanRunnable.java:56)
at com.google.tracing.LocalTraceSpanBuilder.internalContinueSpan(LocalTraceSpanBuilder.java:626)
at com.google.net.rpc3.impl.server.RpcServerChannel.startRpc(RpcServerChannel.java:837)
at com.google.net.rpc3.impl.server.RpcServerChannel.receivedMessage(RpcServerChannel.java:594)
at com.google.net.rpc3.impl.server.RpcServerChannel.access$2700(RpcServerChannel.java:164)
at com.google.net.rpc3.impl.server.RpcServerChannel$TransportCallback.receivedMessage(RpcServerChannel.java:2365)
at com.google.net.rpc3.impl.wire.RpcBaseTransport.receivedMessage(RpcBaseTransport.java:457)
at com.google.apphosting.runtime.udrpc.UdrpcTransport$ServerAdapter.receivedMessage(UdrpcTransport.java:707)
at com.google.apphosting.runtime.udrpc.UdrpcTransport.dispatchPacket(UdrpcTransport.java:384)
at com.google.apphosting.runtime.udrpc.UdrpcTransport.readPackets(UdrpcTransport.java:283)
at com.google.apphosting.runtime.udrpc.UdrpcTransport$1.run(UdrpcTransport.java:100)
at com.google.net.eventmanager.AbstractFutureTask$Sync.innerRun(AbstractFutureTask.java:260)
at com.google.net.eventmanager.AbstractFutureTask.run(AbstractFutureTask.java:121)
at com.google.net.eventmanager.EventManagerImpl.runTask(EventManagerImpl.java:594)
at com.google.net.eventmanager.EventManagerImpl.internalRunWorkerLoop(EventManagerImpl.java:1011)
at com.google.net.eventmanager.EventManagerImpl.runWorkerLoop(EventManagerImpl.java:892)
at com.google.net.eventmanager.WorkerThreadInfo.runWorkerLoop(WorkerThreadInfo.java:161)
at com.google.net.eventmanager.EventManagerImpl$WorkerThread.run(EventManagerImpl.java:1879)
另一个＆＃34;怪异的＆＃34;事情是，看到请求的日志，参数＆＃34; ms＆＃34;和＆＃34; cpu_ms＆＃34;当它丢掉那个例外时几乎是一样的。也许我超越AppEngine限制或超时限制？
[02/Mar/2015:21:11:32 -0800] "POST /tasks/ProcessBlob HTTP/1.1" 200 0 "http://xxx.appspot.com/upload" "AppEngine-Google; (+http://code.google.com/appengine)" "xxx.appspot.com" ms=599492 cpu_ms=32522 queue_name=default task_name=xxx instance=xxx app_engine_release=1.9.18
[02/Mar/2015:23:21:55 -0800] "POST /tasks/ProcessBlob HTTP/1.1" 200 0 "http://xxx.appspot.com/upload" "AppEngine-Google; (+http://code.google.com/appengine)" "xxx.appspot.com" ms=599420 cpu_ms=33262 queue_name=default task_name=xxx instance=xxx app_engine_release=1.9.18
答案 0 :(得分：1)
看起来您遇到了任务队列限制，599949ms == 10分钟。根据文件：
针对自动缩放模块的任务必须完成执行 在10分钟内。如果您的任务需要更多时间或 计算资源，它们可以发送到手动或基本缩放 模块，它们可以运行24小时。
请参阅文档：https://cloud.google.com/appengine/docs/java/taskqueue/overview-push#task_deadlines
我建议将任务分成几个较小的任务，比如说每1000条记录一个任务，可能更小