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https://issues.apache.org/jira/browse/DERBY-3260?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Dyre Tjeldvoll reassigned DERBY-3260:
-------------------------------------
Assignee: Knut Anders Hatlen
Since he created the latest patch
> NullPointerException caused by race condition in GenericActivationHolder
> ------------------------------------------------------------------------
>
> Key: DERBY-3260
> URL: https://issues.apache.org/jira/browse/DERBY-3260
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.0.2.1, 10.1.1.0, 10.1.2.1, 10.1.3.1, 10.2.1.6,
> 10.2.2.0, 10.3.1.4
> Reporter: Robert Yokota
> Assignee: Knut Anders Hatlen
> Priority: Blocker
> Attachments: d3260.diff, GenericActivationHolder.java.diff
>
>
> I have a stress test using Derby 10.3.1.4 which is executing the same
> PreparedStatement using multiple threads concurrently and I consistently get
> the following NPE after several hours of running:
> 2007-12-07 00:48:10.914 GMT Thread[pool-5-thread-25,5,main] (XID = 1219661),
> (SESSIONID = 377), (DATABASE = /usr/ironhide/var/db/opera/derby), (DRDAID =
> null), Failed Statement is: select rdbmsvaria0_.GUID_AND_INDEX as GUID1_3_0_,
> rdbmsvaria0_.VALUE2 as VALUE2_3_0_, rdbmsvaria0_.HOLDER_GUID as HOLDER3_3_0_,
> rdbmsvaria0_.VALUE_TYPE as VALUE4_3_0_, rdbmsvaria0_.VALUE_GUID as
> VALUE5_3_0_, rdbmsvaria0_.DELETED as DELETED3_0_ from VARIABLE rdbmsvaria0_
> where rdbmsvaria0_.GUID_AND_INDEX=? with 1 parameters begin parameter #1:
> 9C202AB9E8356288A9320C9C383A4D2F-11 :end parameter
> java.lang.NullPointerException
> at
> org.apache.derby.impl.sql.GenericActivationHolder.execute(GenericActivationHolder.java:271)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.execute(GenericPreparedStatement.java:368)
> at
> org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(EmbedStatement.java:1203)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(EmbedPreparedStatement.java:1652)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeQuery(EmbedPreparedStatement.java:275)
> at
> org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
> at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
> at org.hibernate.loader.Loader.doQuery(Loader.java:674)
> at
> org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
> at org.hibernate.loader.Loader.loadEntity(Loader.java:1860)
> at
> org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:48)
> at
> org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:42)
> at
> org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3044)
> at
> org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:395)
> at
> org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:375)
> at
> org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:139)
> at
> org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:179)
> at
> org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:103)
> at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:878)
> at org.hibernate.impl.SessionImpl.get(SessionImpl.java:815)
> at org.hibernate.impl.SessionImpl.get(SessionImpl.java:808)
> at sun.reflect.GeneratedMethodAccessor69.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:301)
> at $Proxy41.get(Unknown Source)
> at
> com.approuter.maestro.opera.rdbms.RdbmsContextHolder.getRdbmsVariable(RdbmsContextHolder.java:108)
> at
> com.approuter.maestro.opera.rdbms.RdbmsContextHolder.getVariable(RdbmsContextHolder.java:94)
> at com.approuter.maestro.vm.Frame.getParameter(Frame.java:218)
> at com.approuter.maestro.vm.Task.getParameter(Task.java:1267)
> at
> com.approuter.maestro.vm.CallContextImpl.setOutputParameter(CallContextImpl.java:195)
> at
> com.approuter.maestro.vm.CallContextImpl.getOutputParameterWriter(CallContextImpl.java:264)
> at
> com.approuter.maestro.sdk.mpi.DynamicExecutableActivity$3$1.getWriter(DynamicExecutableActivity.java:249)
> at
> com.approuter.module.xml.XmlSerializeTextActivity$XmlSerializeTextActivityInstance.serialize(XmlSerializeTextActivity.java:43)
> at sun.reflect.GeneratedMethodAccessor161.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> com.approuter.maestro.sdk.mpi.DynamicExecutableActivity.execute(DynamicExecutableActivity.java:332)
> at com.approuter.maestro.activities.Invoke.call(Invoke.java:199)
> at sun.reflect.GeneratedMethodAccessor157.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> com.approuter.maestro.activities.Instruction.call(Instruction.java:22)
> at com.approuter.maestro.vm.Program.call(Program.java:456)
> at com.approuter.maestro.vm.Task.run(Task.java:580)
> at com.approuter.maestro.vm.Task.run(Task.java:531)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
> at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
> at java.util.concurrent.FutureTask.run(FutureTask.java:138)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
> at java.lang.Thread.run(Thread.java:619)
> Cleanup action completed
> Here is the relevant code from GenericActivationHolder.java
> // synchronized (ps)
> {
> /* Has the activation class changed? */
> if (gc != ps.getActivationClass())
> {
> // ensure the statement is valid by rePreparing it.
> ps.rePrepare(getLanguageConnectionContext()); // <-- line 260
> /*
> ** If we get here, it means the PreparedStatement has been
> ** recompiled. Get a new Activation and check whether the
> ** parameters are compatible. If so, transfer the parameters
> ** from the old Activation to the new one, and make that the
> ** current Activation. If not, throw an exception.
> */
> GeneratedClass newGC = ps.getActivationClass();
> BaseActivation newAC = (BaseActivation)
> newGC.newInstance(lcc); // <-- line 271
> DataTypeDescriptor[] newParamTypes =
> ps.getParameterTypes();
> As you can see, the activation class returned by the ExecPreparedStatement is
> null as of line 271, even after having called a rePrepare(...) on the
> prepared statement (line 260). This is most likely due to a race condition.
> Also note that the containing block was formerly synchronized, but has since
> been commented out. From browsing the source in previous versions, the
> synchronized statement appears to have been commented out since before
> 10.0.2.1. It appears the fix is to reintroduce the synchronized block, or at
> least make the block inside the if statement synchronized.
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