This semantics is stated in our append specification attached to HDFS-265. Hflushed data are visible to new readers who open the file after the hflush.
Hairong On Mon, Jan 11, 2010 at 5:33 PM, Jean-Daniel Cryans <jdcry...@apache.org>wrote: > Thanks for the answer Konstantin, good to know. I also see that the > commenter doesn't seem pleased with the fact that the file has to be > reopened ;) > > So basically what I wrongly expected was a tailing feature. Searches > in Jira don't give me a hit, would it make sense to open one? > > In the mean time, I'm ok with recreating the reader. > > Thx, > > J-D > > On Mon, Jan 11, 2010 at 5:15 PM, Konstantin Boudnik <c...@yahoo-inc.com> > wrote: > > Jean, > > > > I believe this is how it has been intended to work. If you take a look at > > the test src/test/hdfs/org/apache/hadoop/hdfs/TestHFlush.java in HDFS > > workspace you'll a comment on this particular aspect in the line 124. > > > > Hope it helps, > > Cos > > > > On 1/11/10 16:42 , Jean-Daniel Cryans wrote: > >> > >> Hi, > >> > >> I'm trying to use the new hflush function from 0.21 so that a > >> SequenceFile.Reader could read edits from a SequenceFile.Writer after > >> a signal on a Condition. If I: > >> > >> create the Writer > >> append entries > >> hflush > >> create the Reader > >> next() through the entries > >> > >> It works fine. But after that if I only next(), using the same reader, > >> after appending/hflush I won't see the new edits. But, if I create a > >> new Reader after calling hflush, it works fine. > >> > >> So this does not work: > >> > >> create the Writer > >> append entries > >> hflush > >> create the Reader > >> next() through the entries > >> append entries > >> hflush > >> next() through the entries > >> append entries > >> hflush > >> next() through the entries > >> > >> This does: > >> > >> create the Writer > >> append entries > >> hflush > >> create the Reader > >> next() through the entries > >> append entries > >> hflush > >> create a new Reader > >> seek > >> next() through the entries > >> > >> Is that the intended behavior? > >> > >> Thx! > >> > >> J-D > > >