hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Colin Patrick McCabe (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-6695) Investigate using Java 7's nonblocking file I/O in BlockReaderLocal to implement read timeouts
Date Fri, 06 Mar 2015 21:36:39 GMT

    [ https://issues.apache.org/jira/browse/HDFS-6695?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14350939#comment-14350939
] 

Colin Patrick McCabe commented on HDFS-6695:
--------------------------------------------

And sending an {{Interrupt}} to a thread that is reading using blocking I/O is "faked" by
closing the FD.

> 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
(v6.3.4#6332)

Mime
View raw message