Maximilian Michels created FLINK-12653:
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Summary: Keyed state backend fails to restore during rescaling
Key: FLINK-12653
URL: https://issues.apache.org/jira/browse/FLINK-12653
Project: Flink
Issue Type: Bug
Components: Runtime / State Backends
Affects Versions: 1.8.0, 1.7.2, 1.6.4
Environment: Beam 2.12.0 or any other Beam version
Flink >= 1.6
Reporter: Maximilian Michels
The Flink Runner includes a test which verifies checkpoints/savepoints work
correctly with Beam on Flink. When adding additional tests for
scaleup/scaledown [1], I came across a bug with restoring the keyed state
backend. After a fair amount of debugging Beam code and checking any potential
issues with serializers, I think this could be a Flink issue.
Steps to reproduce:
1. {{git clone https://github.com/mxm/beam}}
2. {{cd beam && git checkout savepoint-problem}}
3. {{./gradlew :runners:flink:1.6:test --tests
"**.FlinkSavepointTest.testSavepointRestoreLegacy"}}
Error:
{noformat}
java.lang.Exception: Exception while creating StreamOperatorStateContext.
at
org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:192)
at
org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:250)
at
org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738)
at
org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.flink.util.FlinkException: Could not restore keyed state
backend for DoFnOperator_76375152c4a81d5df72cf49e32c4ecb9_(4/4) from any of the
1 provided restore options.
at
org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:137)
at
org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:279)
at
org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:133)
... 5 more
Caused by: java.lang.RuntimeException: Invalid namespace string: ''
at
org.apache.beam.runners.core.StateNamespaces.fromString(StateNamespaces.java:245)
at
org.apache.beam.runners.core.TimerInternals$TimerDataCoder.decode(TimerInternals.java:246)
at
org.apache.beam.runners.core.TimerInternals$TimerDataCoder.decode(TimerInternals.java:221)
at
org.apache.beam.runners.flink.translation.types.CoderTypeSerializer.deserialize(CoderTypeSerializer.java:92)
at
org.apache.flink.streaming.api.operators.TimerSerializer.deserialize(TimerSerializer.java:169)
at
org.apache.flink.streaming.api.operators.TimerSerializer.deserialize(TimerSerializer.java:45)
at
org.apache.flink.runtime.state.KeyGroupPartitioner$PartitioningResultKeyGroupReader.readMappingsInKeyGroup(KeyGroupPartitioner.java:297)
at
org.apache.flink.runtime.state.heap.HeapKeyedStateBackend.readKeyGroupStateData(HeapKeyedStateBackend.java:513)
at
org.apache.flink.runtime.state.heap.HeapKeyedStateBackend.readStateHandleStateData(HeapKeyedStateBackend.java:474)
at
org.apache.flink.runtime.state.heap.HeapKeyedStateBackend.restorePartitionedState(HeapKeyedStateBackend.java:431)
at
org.apache.flink.runtime.state.heap.HeapKeyedStateBackend.restore(HeapKeyedStateBackend.java:370)
at
org.apache.flink.runtime.state.heap.HeapKeyedStateBackend.restore(HeapKeyedStateBackend.java:105)
at
org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:151)
at
org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:123)
... 7 more
{noformat}
It is possible to change the {{maxParallelism}} to other values. The following
lead to failure:
{noformat}
options.setMaxParallelism(128); // default value
options.setMaxParallelism(64);
options.setMaxParallelism(118);
{noformat}
The following work fine:
{noformat}
options.setMaxParallelism(110);
options.setMaxParallelism(63);
options.setMaxParallelism(24);
{noformat}
[1]
https://github.com/apache/beam/commit/52d7291144f64eaa417862558d71a443fae3d690
Everything works fine with RocksDB.
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