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Posted to hdfs-issues@hadoop.apache.org by "Doroszlai, Attila (Jira)" <ji...@apache.org> on 2019/08/26 11:56:00 UTC
[jira] [Work started] (HDDS-2026) Overlapping chunk region cannot
be read concurrently
[ https://issues.apache.org/jira/browse/HDDS-2026?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Work on HDDS-2026 started by Doroszlai, Attila.
-----------------------------------------------
> 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
> Assignee: Doroszlai, Attila
> Priority: Critical
> Attachments: HDDS-2026-repro.patch, changes.diff, first-cut-proposed.diff
>
>
> Concurrent requests to datanode 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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