Question

我有一个appengine模块作为后台实例运行（b4，基本缩放），它迭代大量数据并处理它。

当处理较少量的数据时，它会正确运行，但是当数据变大时，我开始获得多个异常。在开始时，InvocationTargetException会导致MemcacheServiceException，然后由LogAndContinueErrorHandler捕获（请参阅此主题：Backend "Process moved to a different machine" and fails withh error 500）。

大约14秒后又有10个类似的错误，“进程移动到另一台机器上”。我建议原因是appengine识别错误并假设实例出现问题并在一段时间后将其关闭。

正如在另一个线程中所建议的那样，我可以确保，移动到另一台机器会使进程保持运行，但由于它确实存在错误，因为某些东西太大/太长，我最好应该处理错误。

错误级联开始时出现错误，错误在com.googlecode.objectify.cache.MemcacheServiceRetryProxy invoke: Error performing memcache operation, retrying: public abstract void

结束时停止

    15:49:18.779
com.google.appengine.api.memcache.LogAndContinueErrorHandler handleServiceError: Service error in memcache
com.google.appengine.api.memcache.MemcacheServiceException: Memcache getAll: exception getting multiple keys
    at com.google.appengine.api.memcache.MemcacheServiceApiHelper$RpcResponseHandler.handleApiProxyException(MemcacheServiceApiHelper.java:68)
    at com.google.appengine.api.memcache.MemcacheServiceApiHelper$1.absorbParentException(MemcacheServiceApiHelper.java:109)
    at com.google.appengine.api.utils.FutureWrapper.handleParentException(FutureWrapper.java:51)
    at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:90)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.quietGet(MemcacheServiceImpl.java:26)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.getAll(MemcacheServiceImpl.java:64)
    at com.googlecode.objectify.cache.KeyMemcacheService.getAll(KeyMemcacheService.java:75)
    at com.googlecode.objectify.cache.EntityMemcache.cacheGetAll(EntityMemcache.java:346)
    at com.googlecode.objectify.cache.EntityMemcache.putAll(EntityMemcache.java:285)
    at com.googlecode.objectify.cache.CachingAsyncDatastoreService$3.success(CachingAsyncDatastoreService.java:280)
    at com.googlecode.objectify.cache.CachingAsyncDatastoreService$3.success(CachingAsyncDatastoreService.java:269)
    at com.googlecode.objectify.cache.TriggerSuccessFuture.trigger(TriggerSuccessFuture.java:38)
    at com.googlecode.objectify.cache.TriggerFuture.isDone(TriggerFuture.java:89)
    at com.googlecode.objectify.cache.TriggerFuture.get(TriggerFuture.java:104)
    at com.googlecode.objectify.impl.ResultAdapter.now(ResultAdapter.java:34)
    at com.googlecode.objectify.impl.Round$2.now(Round.java:135)
    at com.googlecode.objectify.impl.Round$2.now(Round.java:132)
    at com.googlecode.objectify.impl.LoadEngine$1.nowUncached(LoadEngine.java:172)
    at com.googlecode.objectify.impl.LoadEngine$1.nowUncached(LoadEngine.java:164)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.impl.Round$1.nowUncached(Round.java:73)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.LoadResult.now(LoadResult.java:25)
    at ch.eaternity.server.DAO.loadEntityNow(DAO.java:383)
    at ch.eaternity.server.services.ProductServiceImpl.getProduct(ProductServiceImpl.java:21)
    at ch.eaternity.server.CompositeRoot.restoreJavaObject(CompositeRoot.java:237)
    at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_$1.run(Method_.java:179)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.privilegedInvoke(Method_.java:176)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.invoke_(Method_.java:137)
    at com.google.apphosting.runtime.security.shared.intercept.java.lang.reflect.Method_.invoke(Method_.java:45)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata.invokeLifecycleCallbacks(ConcreteEntityMetadata.java:167)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata.access$000(ConcreteEntityMetadata.java:24)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata$1.run(ConcreteEntityMetadata.java:127)
    at com.googlecode.objectify.impl.translate.LoadContext.done(LoadContext.java:70)
    at com.googlecode.objectify.impl.LoadEngine$1.postExecuteHook(LoadEngine.java:191)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:33)
    at com.googlecode.objectify.impl.Round$1.nowUncached(Round.java:73)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.util.ResultNowFunction.apply(ResultNowFunction.java:20)
    at com.googlecode.objectify.util.ResultNowFunction.apply(ResultNowFunction.java:9)
    at com.google.common.collect.Iterators$8.transform(Iterators.java:794)
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
    at com.googlecode.objectify.impl.Chunk.next(Chunk.java:27)
    at com.googlecode.objectify.impl.Chunk.next(Chunk.java:10)
    at com.google.common.collect.Iterators$5.next(Iterators.java:553)
    at com.google.common.collect.Iterators$PeekingImpl.peek(Iterators.java:1162)
    at com.googlecode.objectify.impl.ChunkingIterator.hasNext(ChunkingIterator.java:52)
    at com.google.common.collect.Iterators.addAll(Iterators.java:356)
    at com.google.common.collect.Lists.newArrayList(Lists.java:147)
    at com.google.common.collect.Lists.newArrayList(Lists.java:129)
    at com.googlecode.objectify.util.MakeListResult.translate(MakeListResult.java:21)
    at com.googlecode.objectify.util.MakeListResult.translate(MakeListResult.java:11)
    at com.googlecode.objectify.util.ResultTranslator.nowUncached(ResultTranslator.java:21)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.util.ResultProxy.invoke(ResultProxy.java:32)
    at com.sun.proxy.$Proxy23.toArray(Unknown Source)
    at java.util.ArrayList.addAll(ArrayList.java:530)
    at ch.eaternity.server.DAO.loadCompositeRootsByDateAndKitchenId(DAO.java:1058)
    at ch.eaternity.server.services.ReportServiceImpl.loadCompositeRoots(ReportServiceImpl.java:75)
    at ch.eaternity.server.services.ReportServiceImpl.loadSupplies(ReportServiceImpl.java:24)
    at ch.eaternity.server.reports.GeneralKitchenDataAnalyzer.generateAndSaveConcreteGeneralKitchenData(GeneralKitchenDataAnalyzer.java:45)
    at ch.eaternity.server.servlets.ReportGeneratingServlet.kickOffReportDataGeneration(ReportGeneratingServlet.java:75)
    at ch.eaternity.server.servlets.ReportGeneratingServlet.doPost(ReportGeneratingServlet.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at ch.eaternity.server.NamespaceFilter.doFilter(NamespaceFilter.java:36)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.googlecode.objectify.cache.AsyncCacheFilter.doFilter(AsyncCacheFilter.java:59)
    at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:49)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    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)
<continued in next message>
   
E
 15:49:18.779
<continued from previous message>
    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$RequestRunnable.run(JavaRuntime.java:480)
    at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:438)
    at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:445)
    at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:309)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:301)
    at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:442)
    at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
    at java.lang.Thread.run(Thread.java:724)
   
I
 15:49:20.272
com.google.appengine.api.memcache.MemcacheServiceApiHelper$RpcResponseHandler handleApiProxyException: Memcache putAll: Unknown exception setting 0 keys: 
   
W
 15:49:20.276
com.googlecode.objectify.cache.MemcacheServiceRetryProxy invoke: Error performing memcache operation, retrying: public abstract void com.google.appengine.api.memcache.MemcacheService.putAll(java.util.Map)
java.lang.reflect.InvocationTargetException
    at com.google.appengine.runtime.Request.process-fdcbff8350bb99f7(Request.java)
    at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:45)
    at com.googlecode.objectify.cache.MemcacheServiceRetryProxy.invoke(MemcacheServiceRetryProxy.java:68)
    at com.sun.proxy.$Proxy10.putAll(Unknown Source)
    at com.googlecode.objectify.cache.KeyMemcacheService.putAll(KeyMemcacheService.java:80)
    at com.googlecode.objectify.cache.EntityMemcache.empty(EntityMemcache.java:312)
    at com.googlecode.objectify.cache.EntityMemcache.putAll(EntityMemcache.java:296)
    at com.googlecode.objectify.cache.CachingAsyncDatastoreService$3.success(CachingAsyncDatastoreService.java:280)
    at com.googlecode.objectify.cache.CachingAsyncDatastoreService$3.success(CachingAsyncDatastoreService.java:269)
    at com.googlecode.objectify.cache.TriggerSuccessFuture.trigger(TriggerSuccessFuture.java:38)
    at com.googlecode.objectify.cache.TriggerFuture.isDone(TriggerFuture.java:89)
    at com.googlecode.objectify.cache.TriggerFuture.get(TriggerFuture.java:104)
    at com.googlecode.objectify.impl.ResultAdapter.now(ResultAdapter.java:34)
    at com.googlecode.objectify.impl.Round$2.now(Round.java:135)
    at com.googlecode.objectify.impl.Round$2.now(Round.java:132)
    at com.googlecode.objectify.impl.LoadEngine$1.nowUncached(LoadEngine.java:172)
    at com.googlecode.objectify.impl.LoadEngine$1.nowUncached(LoadEngine.java:164)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.impl.Round$1.nowUncached(Round.java:73)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.LoadResult.now(LoadResult.java:25)
    at ch.eaternity.server.DAO.loadEntityNow(DAO.java:383)
    at ch.eaternity.server.services.ProductServiceImpl.getProduct(ProductServiceImpl.java:21)
    at ch.eaternity.server.CompositeRoot.restoreJavaObject(CompositeRoot.java:237)
    at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:45)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata.invokeLifecycleCallbacks(ConcreteEntityMetadata.java:167)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata.access$000(ConcreteEntityMetadata.java:24)
    at com.googlecode.objectify.impl.ConcreteEntityMetadata$1.run(ConcreteEntityMetadata.java:127)
    at com.googlecode.objectify.impl.translate.LoadContext.done(LoadContext.java:70)
    at com.googlecode.objectify.impl.LoadEngine$1.postExecuteHook(LoadEngine.java:191)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:33)
    at com.googlecode.objectify.impl.Round$1.nowUncached(Round.java:73)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.util.ResultNowFunction.apply(ResultNowFunction.java:20)
    at com.googlecode.objectify.util.ResultNowFunction.apply(ResultNowFunction.java:9)
    at com.google.common.collect.Iterators$8.transform(Iterators.java:794)
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
    at com.googlecode.objectify.impl.Chunk.next(Chunk.java:27)
    at com.googlecode.objectify.impl.Chunk.next(Chunk.java:10)
    at com.google.common.collect.Iterators$5.next(Iterators.java:553)
    at com.google.common.collect.Iterators$PeekingImpl.peek(Iterators.java:1162)
    at com.googlecode.objectify.impl.ChunkingIterator.hasNext(ChunkingIterator.java:52)
    at com.google.common.collect.Iterators.addAll(Iterators.java:356)
    at com.google.common.collect.Lists.newArrayList(Lists.java:147)
    at com.google.common.collect.Lists.newArrayList(Lists.java:129)
    at com.googlecode.objectify.util.MakeListResult.translate(MakeListResult.java:21)
    at com.googlecode.objectify.util.MakeListResult.translate(MakeListResult.java:11)
    at com.googlecode.objectify.util.ResultTranslator.nowUncached(ResultTranslator.java:21)
    at com.googlecode.objectify.util.ResultCache.now(ResultCache.java:30)
    at com.googlecode.objectify.util.ResultProxy.invoke(ResultProxy.java:32)
    at com.sun.proxy.$Proxy23.toArray(Unknown Source)
    at java.util.ArrayList.addAll(ArrayList.java:530)
    at ch.eaternity.server.DAO.loadCompositeRootsByDateAndKitchenId(DAO.java:1058)
    at ch.eaternity.server.services.ReportServiceImpl.loadCompositeRoots(ReportServiceImpl.java:75)
    at ch.eaternity.server.services.ReportServiceImpl.loadSupplies(ReportServiceImpl.java:24)
    at ch.eaternity.server.reports.GeneralKitchenDataAnalyzer.generateAndSaveConcreteGeneralKitchenData(GeneralKitchenDataAnalyzer.java:45)
    at ch.eaternity.server.servlets.ReportGeneratingServlet.kickOffReportDataGeneration(ReportGeneratingServlet.java:75)
    at ch.eaternity.server.servlets.ReportGeneratingServlet.doPost(ReportGeneratingServlet.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at ch.eaternity.server.NamespaceFilter.doFilter(NamespaceFilter.java:36)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.googlecode.objectify.cache.AsyncCacheFilter.doFilter(AsyncCacheFilter.java:59)
    at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:49)
    at org.mortbay.jetty.servlet.ServletHandler$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:438)
    at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:445)
    at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:309)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:301)
    at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:442)
    at java.lang.Thread.run(Thread.java:724)
Caused by: com.google.appengine.api.memcache.MemcacheServiceException: Memcache putAll: Unknown exception setting 0 keys
    at com.google.appengine.api.memcache.MemcacheServiceApiHelper$RpcResponseHandler.handleApiProxyException(MemcacheServiceApiHelper.java:68)
    at com.google.appengine.api.memcache.AsyncMemcacheServiceImpl$RpcResponseHandlerForPut.handleApiProxyException(AsyncMemcacheServiceImpl.java:348)
    at com.google.appengine.api.memcache.MemcacheServiceApiHelper$1.absorbParentException(MemcacheServiceApiHelper.java:109)
<continued in next message>
   
W
 15:49:20.276
<continued from previous message>
    at com.google.appengine.api.utils.FutureWrapper.handleParentException(FutureWrapper.java:51)
    at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:90)
    at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.quietGet(MemcacheServiceImpl.java:26)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.putAll(MemcacheServiceImpl.java:115)
    ... 91 more

我不确定天气与appengine或objectify相关，请参阅此主题进行比较： https://groups.google.com/forum/#!msg/objectify-appengine/GzFmrQNMaI0/1ALIKbEY9agJ

客观化：4.0RC2 Appengine：1.9.9

更新1 升级到Objectify 4.1.3。之后，不再发生异常，但在迭代中的完全相同的点处发生Process moved to a different machine.警告。为什么它移动到另一台机器？

更新2 与此同时，我达到内存限制的几倍，最后将回溯实例升级到B4，暂时解决了这个问题。

java.lang.RuntimeException: java.lang.OutOfMemoryError: Java heap space

现在错误移动了一点，现在我只得到这个异常大约100次，直到进程被移动到另一台机器。

com.google.appengine.api.memcache.MemcacheServiceException: Memcache getAll: exception getting multiple keys

更新3 有时批处理也会成功运行！我不明白......我会试着弄清楚它什么时候不成功。

任何人都知道问题可能来自哪里？怎么解决？非常感谢你！

Answer 1

我没有直接回答你的问题，但我可以对Objectify（和GAE的）行为WRT内存提供一些启示。

Objectify使用memcache作为直读缓存，因此＆＃34; memcache不可用＆＃34;出于所有实际目的，与＃34;空结果相同＆＃34; - Objectify将数据从数据存储区中取出。对于这个目的，GAE的memcache API有一个LogAndContinueErrorHandler - 记录了memecache错误，但忽略了。

不幸的是，谷歌LogAndContinueErrorHandler有一个错误，即某些类型的内存缓存错误既未被记录也未被忽略。 Objectify得到了一些新的行为（恰当命名的MemcacheServiceRetryProxy），它重试几次memcache API调用，然后放弃，返回一个空的结果。这就是你所看到的4.0RC2。

一段时间后，Google修改了处理程序，而不是通过更改LogAndContinueErrorHandler的行为（可能认为某些用户可能依赖于确切的行为），而是弃用该类并添加ConsistentLogAndContinueErrorHandler行为......更一致Objectify的更高版本转而使用此工具，现在您已经看到了4.1.3的行为 - 减少噪音。

这就是故事的一部分。故事的另一部分是，在某些时候，Objectify对于优化对memcache的调用只是有点过于自以为是，有时会将memcache调用优化为零长度的键列表。 memcache API不是那样的，可能负责Memcache putAll: Unknown exception setting 0 keys。如果没有操作，更新版本的Objectify会跳过memcache调用。

至于Process moved to a different machine.，我不知道。它可能是相关的，也可能不是。

Answer 2

关于在不同实例上向上移动的过程，无论如何都无法控制它。机器可能随时关闭，应用程序引擎会将您的进程转移到另一台机器。您的任务最好是幂等的。

Memcache（InnvocationTargetException）炸毁了Backend Instance

2 个答案: