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From "dhruba borthakur (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-1700) Append to files in HDFS
Date Tue, 04 Mar 2008 20:51:40 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-1700?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12575133#action_12575133
] 

dhruba borthakur commented on HADOOP-1700:
------------------------------------------

Most of the JIRA linked to this one are fixed or have patches associated with them. That means
mos tof the pre-resuisites for supporting appends are already done. i am currently working
on a distributed upgrade to upgrade a current cluster to the new disk format (HADOOP-2656).

Once the above pre-requisites are done, the new code for supporting Appends will be started.
I am guessing it will be another 1.5 man month before it appears as a draft patch.

> Append to files in HDFS
> -----------------------
>
>                 Key: HADOOP-1700
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1700
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: dfs
>    Affects Versions: 0.15.1
>            Reporter: stack
>         Attachments: append.patch, Appends.doc, Appends.doc, Appends.html
>
>
> Request for being able to append to files in HDFS has been raised a couple of times on
the list of late.   For one example, see http://www.nabble.com/HDFS%2C-appending-writes-status-tf3848237.html#a10916193.
 Other mail describes folks' workarounds because this feature is lacking: e.g. http://www.nabble.com/Loading-data-into-HDFS-tf4200003.html#a12039480
(Later on this thread, Jim Kellerman re-raises the HBase need of this feature).  HADOOP-337
'DFS files should be appendable' makes mention of file append but it was opened early in the
life of HDFS when the focus was more on implementing the basics rather than adding new features.
 Interest fizzled.  Because HADOOP-337 is also a bit of a grab-bag -- it includes truncation
and being able to concurrently read/write -- rather than try and breathe new life into HADOOP-337,
instead, here is a new issue focused on file append.  Ultimately, being able to do as the
google GFS paper describes -- having multiple concurrent clients making 'Atomic Record Append'
to a single file would be sweet but at least for a first cut at this feature, IMO, a single
client appending to a single HDFS file letting the application manage the access would be
sufficent.

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