[
https://issues.apache.org/jira/browse/FLINK-3713?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15230058#comment-15230058
]
Konstantin Knauf commented on FLINK-3713:
-----------------------------------------
Just for my understanding:
It says there
{quote}
Disposing custom state handles: Disposing an old savepoint does not work with
custom state handles (if you are using a custom state backend), because the
user code class loader is not available during disposal.
{quote}
We are using FsStateBackend, not a custome state backend. Or does "custom state
backend" always mean user classes?
Let me give you some context, maybe we can come up with a different solution:
We have a streaming job, which should always be running. Normally, flink should
handle failures, but we can not solely rely on it (max restart attempts, some
bug,..). So we have a script, which runs regularly and checks if the job is
still running. If it is not running over a period of x minutes (to take account
for automatic recovery by flink) the job is restarted again from a savepoint.
Everytime this script runs a new savepoint is triggered, and the old one is
discarded. So we need this regular savepoint to be able to do this "manual"
recovery. So we are triggering quite a lot of savepoints and need some way of
cleaning up the old ones. Do you have a different idea how to do this cleanup?
Just deleting the directory in HDFS? If you have a complete different idea how
to handle this supervision, I am also happy about suggestions.
> DisposeSavepoint message uses system classloader to discard state
> -----------------------------------------------------------------
>
> Key: FLINK-3713
> URL: https://issues.apache.org/jira/browse/FLINK-3713
> Project: Flink
> Issue Type: Bug
> Components: JobManager
> Reporter: Robert Metzger
>
> The {{DisposeSavepoint}} message in the JobManager is using the system
> classloader to discard the state:
> {code}
> val savepoint = savepointStore.getState(savepointPath)
> log.debug(s"$savepoint")
> // Discard the associated checkpoint
> savepoint.discard(getClass.getClassLoader)
> // Dispose the savepoint
> savepointStore.disposeState(savepointPath)
> {code}
> Which leads to issues when the state contains user classes:
> {code}
> 2016-04-07 03:02:12,225 INFO org.apache.flink.yarn.YarnJobManager
> - Disposing savepoint at
> 'hdfs:/bigdata/flink/savepoints/savepoint-7610540d089f'.
> 2016-04-07 03:02:12,233 WARN
> org.apache.flink.runtime.checkpoint.StateForTask - Failed to
> discard checkpoint state: StateForTask eed5cc5a12dc2e0672848ba81bd8fa6d-0 :
> SerializedValue
> java.lang.ClassNotFoundException:
> <some_package>.MetricsProcessor$CombinedKeysFoldFunction
> at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
> at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
> at java.lang.Class.forName0(Native Method)
> at java.lang.Class.forName(Class.java:270)
> at
> org.apache.flink.util.InstantiationUtil$ClassLoaderObjectInputStream.resolveClass(InstantiationUtil.java:64)
> at
> java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1612)
> at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1517)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1771)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at
> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
> at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at
> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
> at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
> at java.util.HashMap.readObject(HashMap.java:1184)
> at sun.reflect.GeneratedMethodAccessor12.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:606)
> at
> java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
> at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at
> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
> at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1706)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1344)
> at
> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
> at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
> at
> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
> at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
> at
> org.apache.flink.util.InstantiationUtil.deserializeObject(InstantiationUtil.java:290)
> at
> org.apache.flink.util.SerializedValue.deserializeValue(SerializedValue.java:58)
> at
> org.apache.flink.runtime.checkpoint.StateForTask.discard(StateForTask.java:109)
> at
> org.apache.flink.runtime.checkpoint.CompletedCheckpoint.discard(CompletedCheckpoint.java:85)
> at
> org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply$mcV$sp(JobManager.scala:635)
> at
> org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply(JobManager.scala:627)
> at
> org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply(JobManager.scala:627)
> at
> scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
> at
> scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
> at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)
> at
> akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:401)
> at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
> at
> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.pollAndExecAll(ForkJoinPool.java:1253)
> at
> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1346)
> at
> scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
> at
> scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
> {code}
> The issue was reported by [~knaufk] and analyzed by [~aljoscha].
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
