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https://issues.apache.org/jira/browse/FLINK-5801?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15876416#comment-15876416
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Ufuk Celebi commented on FLINK-5801:
------------------------------------
The root cause of this a mismatch in the key serializers. The client Scala code
creates a generic KryoSerializer, because the scala.Long type cannot be
captured at runtime.
A work around is to use a macro when creating the serializers:
{code}
import org.apache.flink.streaming.api.scala._
...
val keySerializer = createTypeInformation[Long].createSerializer(new
ExecutionConfig)
{code}
I created FLINK-5876 for adding a note to the docs. Sorry for the inconvenience
this has caused.
> Queryable State from Scala job/client fails with key of type Long
> -----------------------------------------------------------------
>
> Key: FLINK-5801
> URL: https://issues.apache.org/jira/browse/FLINK-5801
> Project: Flink
> Issue Type: Bug
> Components: Queryable State
> Affects Versions: 1.2.0
> Environment: Flink 1.2.0
> Scala 2.10
> Reporter: Patrick Lucas
> Assignee: Ufuk Celebi
> Attachments: OrderFulfillment.scala, OrderFulfillmentStateQuery.scala
>
>
> While working on a demo Flink job, to try out Queryable State, I exposed some
> state of type Long -> custom class via the Query server. However, the query
> server returned an exception when I tried to send a query:
> {noformat}
> Exception in thread "main" java.lang.RuntimeException: Failed to query state
> backend for query 0. Caused by: java.io.IOException: Unable to deserialize
> key and namespace. This indicates a mismatch in the key/namespace serializers
> used by the KvState instance and this access.
> at
> org.apache.flink.runtime.query.netty.message.KvStateRequestSerializer.deserializeKeyAndNamespace(KvStateRequestSerializer.java:392)
> at
> org.apache.flink.runtime.state.heap.AbstractHeapState.getSerializedValue(AbstractHeapState.java:130)
> at
> org.apache.flink.runtime.query.netty.KvStateServerHandler$AsyncKvStateQueryTask.run(KvStateServerHandler.java:220)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.io.EOFException
> at
> org.apache.flink.runtime.util.DataInputDeserializer.readLong(DataInputDeserializer.java:217)
> at
> org.apache.flink.api.common.typeutils.base.LongSerializer.deserialize(LongSerializer.java:69)
> at
> org.apache.flink.api.common.typeutils.base.LongSerializer.deserialize(LongSerializer.java:27)
> at
> org.apache.flink.runtime.query.netty.message.KvStateRequestSerializer.deserializeKeyAndNamespace(KvStateRequestSerializer.java:379)
> ... 7 more
> at
> org.apache.flink.runtime.query.netty.KvStateServerHandler$AsyncKvStateQueryTask.run(KvStateServerHandler.java:257)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> I banged my head against this for a while, then per [~jgrier]'s suggestion I
> tried simply changing the key from Long to String (modifying the two
> {{keyBy}} calls and the {{keySerializer}} {{TypeHint}} in the attached code)
> and it started working perfectly.
> cc [~uce]
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