Yes makes sense. My use-case is more like a producer/consumer and consumer trying to stream data as it arrives. Has anyone hit this before and if so resolved it in a better way.
Apologies, if i am digressing from the subject of this thread however seems to land in the bucket of append support in HDFS. - Inder On Mon, Apr 9, 2012 at 6:27 PM, Harsh J <ha...@cloudera.com> wrote: > Inder, > > Yes, that is a requirement for readers of sync-ing data. The new meta > entries can only be read by new readers. The read code would end up > being exactly like the implementation for method "fs -tail" at > > http://svn.apache.org/viewvc/hadoop/common/branches/branch-1/src/core/org/apache/hadoop/fs/FsShell.java?view=markup > (Line 1101) > > HBase does not read the WAL (HLog) continuously/vigorously as it > syncs, by the way. It only reads the them when a specific request is > made (for splitting, replaying and debug-printing). > > On Mon, Apr 9, 2012 at 6:05 PM, Inder Pall <inder.p...@gmail.com> wrote: > > Based on what i have tried, after a sync you need to open a new Reader. > > Please correct if that's not the write semantics. > > > > Thanks, > > - Inder > > > > > > On Mon, Apr 9, 2012 at 4:23 PM, Harsh J <ha...@cloudera.com> wrote: > >> > >> I'd also like to note that there are some unresolved issues with the > >> append version in the 1.x (stable) line. > >> > >> Note that HBase's use of the 0.20-append branch features are limited > >> to using "sync" calls alone (Described in p68 "Coherency Model", > >> Chapter 3 (The Hadoop Distributed File System) in Hadoop: The > >> Definitive Guide, 2nd Edition (O'Reilly)). Not the file-reopening > >> "append" calls. The latter is what is still with issues in the 1.x > >> releases today. Using the former is alright if its done in the way > >> similar to HBase's WAL (HLog) (or for similar needs). > >> > >> On Mon, Apr 9, 2012 at 3:45 PM, Ioan Eugen Stan <stan.ieu...@gmail.com> > >> wrote: > >> > 2012/4/7 Florin P <florinp...@yahoo.com>: > >> >> Hello! > >> >> Just google it for supporting of append into HDFS files and the > >> >> result: > >> >> I'm puzzled. Can someone say: YES you can append in TextFile or > >> >> SequenceFile > >> >> or whatever format. If yes, in which version this feature is > supported > >> >> ? > >> >> Also where can I find a good example of using the API? I know that > is a > >> >> long > >> >> debate about this subject, but really it is challenge to find on the > >> >> google > >> >> the current status of this feature. > >> >> I look forward for a trust source answer. > >> >> Thank you, > >> >> Regards, > >> >> Florin > >> > > >> > Hi Florian, > >> > > >> > HDFS supports append in Hadoop 1.0.x branch and also 0.22 (a.k.a > >> > hadoop 2.x branch) and 0.23 (a.k.a hadoop 3.x branch). > >> > > >> > [1] http://hbase.apache.org/book/hadoop.html > >> > [2] http://hbase.apache.org/book/hadoop.html -- search for append in > >> > release notes > >> > > >> > Cheers, > >> > -- > >> > Ioan Eugen Stan > >> > http://ieugen.blogspot.com/ > >> > >> > >> > >> -- > >> Harsh J > > > > > > > > > > -- > > Thanks, > > - Inder > > Tech Platforms @Inmobi > > Linkedin - http://goo.gl/eR4Ub > > > > -- > Harsh J > -- Thanks, - Inder Tech Platforms @Inmobi Linkedin - http://goo.gl/eR4Ub
