[
https://issues.apache.org/jira/browse/FLINK-6061?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15925929#comment-15925929
]
Stefan Richter edited comment on FLINK-6061 at 3/15/17 11:19 AM:
-----------------------------------------------------------------
Thanks for reporting this. I agree that the information from the
`IllegalStateException` is helpful to the user. I will add this to the RocksDB
states. However, the behaviour is correct: there is no key context during this
initialization, only when processing an element, the key that is extracted from
that element determines the key context of the backend.
was (Author: srichter):
Thanks for reporting this. I agree that the information from the
`IllegalStateException` is helpful to the user. I will add this to the RocksDB
states.
> NPE on TypeSerializer.serialize with a RocksDBStateBackend calling entries()
> on a keyed state in the open() function
> --------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-6061
> URL: https://issues.apache.org/jira/browse/FLINK-6061
> Project: Flink
> Issue Type: Bug
> Components: DataStream API, State Backends, Checkpointing, Streaming
> Affects Versions: 1.3.0
> Reporter: Vladislav Pernin
>
> With a default state (heap), the call to state.entries() "nicely fails" with
> a IllegalStateException :
> {noformat}
> Caused by: java.lang.IllegalStateException: No key set.
> at
> org.apache.flink.util.Preconditions.checkState(Preconditions.java:195)
> at
> org.apache.flink.runtime.state.heap.HeapMapState.entries(HeapMapState.java:188)
> at
> org.apache.flink.runtime.state.UserFacingMapState.entries(UserFacingMapState.java:77)
> at
> org.apache.flink.Reproducer$FailingMapWithState.open(Reproducer.java:78)
> at
> org.apache.flink.api.common.functions.util.FunctionUtils.openFunction(FunctionUtils.java:36)
> at
> org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.open(AbstractUdfStreamOperator.java:112)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.openAllOperators(StreamTask.java:376)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:252)
> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:670)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> With a RocksDBStateBackend, it fails with a NPE :
> {noformat}
> Caused by: java.lang.NullPointerException
> at
> org.apache.flink.api.common.typeutils.base.ShortSerializer.serialize(ShortSerializer.java:64)
> at
> org.apache.flink.api.common.typeutils.base.ShortSerializer.serialize(ShortSerializer.java:27)
> at
> org.apache.flink.contrib.streaming.state.AbstractRocksDBState.writeKey(AbstractRocksDBState.java:181)
> at
> org.apache.flink.contrib.streaming.state.AbstractRocksDBState.writeKeyWithGroupAndNamespace(AbstractRocksDBState.java:163)
> at
> org.apache.flink.contrib.streaming.state.AbstractRocksDBState.writeCurrentKeyWithGroupAndNamespace(AbstractRocksDBState.java:148)
> at
> org.apache.flink.contrib.streaming.state.RocksDBMapState.serializeCurrentKeyAndNamespace(RocksDBMapState.java:263)
> at
> org.apache.flink.contrib.streaming.state.RocksDBMapState.iterator(RocksDBMapState.java:196)
> at
> org.apache.flink.contrib.streaming.state.RocksDBMapState.entries(RocksDBMapState.java:143)
> at
> org.apache.flink.runtime.state.UserFacingMapState.entries(UserFacingMapState.java:77)
> at
> org.apache.flink.Reproducer$FailingMapWithState.open(Reproducer.java:78)
> at
> org.apache.flink.api.common.functions.util.FunctionUtils.openFunction(FunctionUtils.java:36)
> at
> org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.open(AbstractUdfStreamOperator.java:112)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.openAllOperators(StreamTask.java:376)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:252)
> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:670)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> The reason is that the record is null, because backend.getCurrentKey() is
> null (not yet set) in AbstractRocksDBState.
> This may also be the case for other RockDBState implementations.
> You can find the reproducer here based on 1.3-SNAPSHOT (needed for the
> MapState) :
> https://github.com/vpernin/flink-rocksdbstate-npe
> The reproducer is a non sense application. There is no MapState with TTL or
> expiration yet, so the goal is to try to shrink or expire the state at some
> interval.
> This could be done by iterating over the entries of the state and removing
> some of them.
> This could probably not be done in the open() method of a rich function.
> I also tried to implement CheckpointListener and to access the state content
> in notifyCheckpointComplete() method, but it fails to, I guess due to the
> asynchronous nature of the checkpoint.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
