[jira] [Created] (HDDS-2026) Overlapping chunk region cannot be read concurrently

["Doroszlai, Attila (Jira)" <ji...@apache.org>]

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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