[
https://issues.apache.org/jira/browse/HDFS-6695?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14064291#comment-14064291
]
Andrew Purtell commented on HDFS-6695:
--------------------------------------
bq. If it uses the underlying asynchronous I/O primitives provided by the
operating system, then it would probably be useful for implementing these
timeouts.
Some grepping around the 7u forest doesn't reveal any native AIO support for
Linux. Search wasn't exhaustive though.
> Investigate using Java 7's nonblocking file I/O in BlockReaderLocal to
> implement read timeouts
> ----------------------------------------------------------------------------------------------
>
> Key: HDFS-6695
> URL: https://issues.apache.org/jira/browse/HDFS-6695
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Colin Patrick McCabe
>
> In BlockReaderLocal, the "read" system call could block for a long time if
> the disk drive is having problems, or there is a huge amount of I/O
> contention. This might cause poor latency performance.
> In the remote block readers, we have implemented a read timeout, but we don't
> have one for the local block reader, since {{FileChannel#read}} doesn't
> support this.
> Once we move to JDK 7, we should investigate the {{java.nio.file}}
> nonblocking file I/O package to see if it could be used to implement read
> timeouts.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
