Doroszlai, Attila created HDDS-2026:
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Summary: Overlapping chunk region cannot be read concurrently
Key: HDDS-2026
URL: https://issues.apache.org/jira/browse/HDDS-2026
Project: Hadoop Distributed Data Store
Issue Type: Bug
Components: Ozone Datanode
Reporter: Doroszlai, Attila
Concurrent requests to for the same chunk may result in the following exception
in datanode:
{code}
java.nio.channels.OverlappingFileLockException
at java.base/sun.nio.ch.FileLockTable.checkList(FileLockTable.java:229)
at java.base/sun.nio.ch.FileLockTable.add(FileLockTable.java:123)
at
java.base/sun.nio.ch.AsynchronousFileChannelImpl.addToFileLockTable(AsynchronousFileChannelImpl.java:178)
at
java.base/sun.nio.ch.SimpleAsynchronousFileChannelImpl.implLock(SimpleAsynchronousFileChannelImpl.java:185)
at
java.base/sun.nio.ch.AsynchronousFileChannelImpl.lock(AsynchronousFileChannelImpl.java:118)
at
org.apache.hadoop.ozone.container.keyvalue.helpers.ChunkUtils.readData(ChunkUtils.java:175)
at
org.apache.hadoop.ozone.container.keyvalue.impl.ChunkManagerImpl.readChunk(ChunkManagerImpl.java:213)
at
org.apache.hadoop.ozone.container.keyvalue.KeyValueHandler.handleReadChunk(KeyValueHandler.java:574)
at
org.apache.hadoop.ozone.container.keyvalue.KeyValueHandler.handle(KeyValueHandler.java:195)
at
org.apache.hadoop.ozone.container.common.impl.HddsDispatcher.dispatchRequest(HddsDispatcher.java:271)
at
org.apache.hadoop.ozone.container.common.impl.HddsDispatcher.dispatch(HddsDispatcher.java:148)
at
org.apache.hadoop.ozone.container.common.transport.server.GrpcXceiverService$1.onNext(GrpcXceiverService.java:73)
at
org.apache.hadoop.ozone.container.common.transport.server.GrpcXceiverService$1.onNext(GrpcXceiverService.java:61)
{code}
It seems this is covered by retry logic, as key read is eventually successful
at client side.
The problem is that:
bq. File locks are held on behalf of the entire Java virtual machine. They are
not suitable for controlling access to a file by multiple threads within the
same virtual machine.
([source|https://docs.oracle.com/javase/8/docs/api/java/nio/channels/FileLock.html])
code ref:
[{{ChunkUtils.readData}}|https://github.com/apache/hadoop/blob/c92de8209d1c7da9e7ce607abeecb777c4a52c6a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java#L175]
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