GitHub user sumitchawla opened a pull request:
https://github.com/apache/incubator-beam/pull/1061
BEAM-724 - Null pointer fix
This seems like a timing Issue. Its reproducible in case where Kafka topic
does not exist yet. The UDF operator run is not called yet, but other thread
calls snapshot before that:
```
java.lang.RuntimeException: Error while triggering checkpoint for Source:
Read(UnboundedKafkaSource) -> ParDo(KafkaRecordToCTuple) ->
ParDo(NetFlowToFlowContentTransformation) ->
ParDo(FlowContentToRelationsTransformation) -> ParDo(GraphToJsonTransformation)
-> AnonymousParDo -> ParDo(KafkaWriter) (1/1)
at org.apache.flink.runtime.taskmanager.Task$2.run(Task.java:949)
at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.Exception: Failed to draw state snapshot from
function: null
at
org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.snapshotOperatorState(AbstractUdfStreamOperator.java:132)
at
org.apache.flink.streaming.runtime.tasks.StreamTask.performCheckpoint(StreamTask.java:598)
at
org.apache.flink.streaming.runtime.tasks.StreamTask.triggerCheckpoint(StreamTask.java:565)
at org.apache.flink.runtime.taskmanager.Task$2.run(Task.java:941)
... 5 more
Caused by: java.lang.NullPointerException
at
org.apache.beam.runners.flink.translation.wrappers.streaming.io.UnboundedSourceWrapper.snapshotState(UnboundedSourceWrapper.java:340)
at
org.apache.beam.runners.flink.translation.wrappers.streaming.io.UnboundedSourceWrapper.snapshotState(UnboundedSourceWrapper.java:54)
at
org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.snapshotOperatorState(AbstractUdfStreamOperator.java:129)
... 8 more
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/sumitchawla/incubator-beam beam_724_fix
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-beam/pull/1061.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1061
----
commit 5da04d6a1c79e2daf17da435030dffad07a1d175
Author: Sumit Chawla <[email protected]>
Date: 2016-10-06T19:42:20Z
BEAM-724 - Null pointer fix
----
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