hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Tsz Wo (Nicholas), SZE (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-3107) HDFS truncate
Date Tue, 20 Mar 2012 17:39:39 GMT

    [ https://issues.apache.org/jira/browse/HDFS-3107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13233603#comment-13233603

Tsz Wo (Nicholas), SZE commented on HDFS-3107:

Easy, Milind.  :)  I do agree with Suresh that (2) is not a very good reason to have truncate.
 I think such accidence is rare.  However, you made a good point that having append without
truncate is a deficiency.
> HDFS truncate
> -------------
>                 Key: HDFS-3107
>                 URL: https://issues.apache.org/jira/browse/HDFS-3107
>             Project: Hadoop HDFS
>          Issue Type: New Feature
>          Components: data-node, name-node
>            Reporter: Lei Chang
>         Attachments: HDFS_truncate_semantics_Mar15.pdf
>   Original Estimate: 1,344h
>  Remaining Estimate: 1,344h
> Systems with transaction support often need to undo changes made to the underlying storage
when a transaction is aborted. Currently HDFS does not support truncate (a standard Posix
operation) which is a reverse operation of append, which makes upper layer applications use
ugly workarounds (such as keeping track of the discarded byte range per file in a separate
metadata store, and periodically running a vacuum process to rewrite compacted files) to overcome
this limitation of HDFS.

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira


View raw message