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https://issues.apache.org/jira/browse/HDFS-4273?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Binglin Chang updated HDFS-4273:
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Status: Patch Available (was: Open)
> Problem in DFSInputStream read retry logic may cause early failure
> ------------------------------------------------------------------
>
> Key: HDFS-4273
> URL: https://issues.apache.org/jira/browse/HDFS-4273
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Binglin Chang
> Assignee: Binglin Chang
> Priority: Minor
> Attachments: TestDFSInputStream.java
>
>
> Assume the following call logic
> {noformat}
> readWithStrategy()
> -> blockSeekTo()
> -> readBuffer()
> -> reader.doRead()
> -> seekToNewSource() add currentNode to deadnode, wish to get a
> different datanode
> -> blockSeekTo()
> -> chooseDataNode()
> -> block missing, clear deadNodes and pick the currentNode again
> seekToNewSource() return false
> readBuffer() re-throw the exception quit loop
> readWithStrategy() got the exception, and may fail the read call before
> tried MaxBlockAcquireFailures.
> {noformat}
> some issues of the logic:
> 1. seekToNewSource() logic is broken because it may clear deadNodes in the
> middle.
> 2. the variable "int retries=2" in readWithStrategy seems have conflict with
> MaxBlockAcquireFailures, should it be removed?
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