On Fri, 2007-09-07 at 23:44 -0700, eric baldeschwieler (JIRA) wrote: > eric baldeschwieler commented on HADOOP-1700: > Yes, I'd thought of using length too. We have had requests to support > truncate as well. > I'm on the fence on that one. It is simple and more provably correct if we > don't do > truncates and just track block length. > But we've a significant client group that has had an interest in truncates.
I think truncates would make the problem a whole lot more complicated and delay the feature that we really need (appends). How about doing appends first and document how we might do truncates if there insights with respect to truncates that come out of the append implementation? > > 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. > -- Jim Kellerman, Senior Engineer; Powerset [EMAIL PROTECTED]
