Question

From time to time I got the following exception message on GAE for my
GAE/J app. I searched with Google, no relevant results were found. Does
anyone know about this? Thanks in advance for any response!

The exception message is as below:

Nested in
org.springframework.orm.jpa.JpaSystemException:
Illegal argument; nested exception is
javax.persistence.PersistenceException:
Illegal argument:
java.lang.IllegalArgumentException:
read operations inside transactions
can’t allow failover
at com.google.appengine.api.datastore.DatastoreApiHelper.translateError(DatastoreApiHelper.java:
34)
at com.google.appengine.api.datastore.DatastoreApiHelper.makeSyncCall(DatastoreApiHelper.java:
67)
at com.google.appengine.api.datastore.DatastoreServiceImpl
$1.run(DatastoreServiceImpl.java:128)
at com.google.appengine.api.datastore.TransactionRunner.runInTransaction(TransactionRunner.java:
30)
at com.google.appengine.api.datastore.DatastoreServiceImpl.get(DatastoreServiceImpl.java:
111)
at com.google.appengine.api.datastore.DatastoreServiceImpl.get(DatastoreServiceImpl.java:
84)
at com.google.appengine.api.datastore.DatastoreServiceImpl.get(DatastoreServiceImpl.java:
77)
at org.datanucleus.store.appengine.RuntimeExceptionWrappingDatastoreService.get(RuntimeExceptionWrappingDatastoreService.java:
53)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.get(DatastorePersistenceHandler.java:
94)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.get(DatastorePersistenceHandler.java:
106)
at org.datanucleus.store.appengine.DatastorePersistenceHandler.fetchObject(DatastorePersistenceHandler.java:
464)
at org.datanucleus.state.JDOStateManagerImpl.loadUnloadedFieldsInFetchPlan(JDOStateManagerImpl.java:
1627)
at org.datanucleus.state.JDOStateManagerImpl.loadFieldsInFetchPlan(JDOStateManagerImpl.java:
1603)
at org.datanucleus.ObjectManagerImpl.performDetachAllOnCommitPreparation(ObjectManagerImpl.java:
3192)
at org.datanucleus.ObjectManagerImpl.preCommit(ObjectManagerImpl.java:
2931)
at org.datanucleus.TransactionImpl.internalPreCommit(TransactionImpl.java:
369)
at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:256)
at org.datanucleus.jpa.EntityTransactionImpl.commit(EntityTransactionImpl.java:
104)
at org.datanucleus.store.appengine.jpa.DatastoreEntityTransactionImpl.commit(DatastoreEntityTransactionImpl.java:
55)
at name.kenyth.playtweets.service.Tx.run(Tx.java:39)
at name.kenyth.playtweets.web.controller.TwitterApiController.persistStatus(TwitterApiController.java:
309)
at name.kenyth.playtweets.web.controller.TwitterApiController.processStatusesForWebCall(TwitterApiController.java:
271)
at name.kenyth.playtweets.web.controller.TwitterApiController.getHomeTimelineUpdates_aroundBody0(TwitterApiController.java:
247)
at name.kenyth.playtweets.web.controller.TwitterApiController
$AjcClosure1.run(TwitterApiController.java:1)
at name.kenyth.playtweets.web.refine.AuthenticationEnforcement.ajc
$around$name_kenyth_playtweets_web_refine_AuthenticationEnforcement
$2$439820b7proceed(AuthenticationEnforcement.aj:1)
at name.kenyth.playtweets.web.refine.AuthenticationEnforcement.ajc
$around$name_kenyth_playtweets_web_refine_AuthenticationEnforcement
$2$439820b7(AuthenticationEnforcement.aj:168)
at name.kenyth.playtweets.web.controller.TwitterApiController.getHomeTimelineUpdates(TwitterApiController.java:
129)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown
Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown
Source)
at java.lang.reflect.Method.invoke(Method.java:43)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:
710)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:
167)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:
414)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:
402)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:
771)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:
716)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:
647)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:
552)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:693)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
511)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
390)
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.servlet.Dispatcher.forward(Dispatcher.java:327)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:126)
at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:
195)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:
159)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:
141)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:
90)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:
417)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:
71)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:
76)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:
88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:
76)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:
97)
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.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:
238)
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
$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:
76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:
135)
at com.google.apphosting.runtime.JavaRuntime.handleRequest(JavaRuntime.java:
250)
at com.google.apphosting.base.RuntimePb$EvaluationRuntime
$6.handleBlockingRequest(RuntimePb.java:5838)
at com.google.apphosting.base.RuntimePb$EvaluationRuntime
$6.handleBlockingRequest(RuntimePb.java:5836)
at com.google.net.rpc.impl.BlockingApplicationHandler.handleRequest(BlockingApplicationHandler.java:
24)
at com.google.net.rpc.impl.RpcUtil.runRpcInApplication

Answer 1

It looks like you’re asking for failover reads, using the new support for this, inside a transaction. As the error message explains, this isn’t possible, because in order to be transactional, it has to always read the most recent data. You need to disable failover reads for operations inside transactions.