[jira] Commented: (HADOOP-1700) Append to files in HDFS

["Doug Cutting (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-1700?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12524866 ] 

Doug Cutting commented on HADOOP-1700:
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Sameer, can you please succinctly state what you think the relative advantages and disadvantages of using new block ids versus blockids plus non-persistent version timestamps?  I've stated what I think these are above, namely that new block ids use slightly less memory, increase the number of persisted events and simplify semantics and recovery.  The last item is I believe the most significant.

> Append to files in HDFS
> -----------------------
>
>                 Key: HADOOP-1700
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1700
>             Project: Hadoop
>          Issue Type: New Feature
>          Components: dfs
>            Reporter: stack
>
> 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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