Then one could MMap the blocks pertaining to the HDFS file and piece them together. Lucene's MMapDirectory implementation does just this to avoid an obscure JVM bug.
On Mon, Apr 11, 2011 at 9:09 PM, Ted Dunning <tdunn...@maprtech.com> wrote: > Yes. But only one such block. That is what I meant by chunk. > That is fine if you want that chunk but if you want to mmap the entire file, > it isn't real useful. > > On Mon, Apr 11, 2011 at 6:48 PM, Jason Rutherglen > <jason.rutherg...@gmail.com> wrote: >> >> What do you mean by local chunk? I think it's providing access to the >> underlying file block? >> >> On Mon, Apr 11, 2011 at 6:30 PM, Ted Dunning <tdunn...@maprtech.com> >> wrote: >> > Also, it only provides access to a local chunk of a file which isn't >> > very >> > useful. >> > >> > On Mon, Apr 11, 2011 at 5:32 PM, Edward Capriolo <edlinuxg...@gmail.com> >> > wrote: >> >> >> >> On Mon, Apr 11, 2011 at 7:05 PM, Jason Rutherglen >> >> <jason.rutherg...@gmail.com> wrote: >> >> > Yes you can however it will require customization of HDFS. Take a >> >> > look at HDFS-347 specifically the HDFS-347-branch-20-append.txt >> >> > patch. >> >> > I have been altering it for use with HBASE-3529. Note that the >> >> > patch >> >> > noted is for the -append branch which is mainly for HBase. >> >> > >> >> > On Mon, Apr 11, 2011 at 3:57 PM, Benson Margulies >> >> > <bimargul...@gmail.com> wrote: >> >> >> We have some very large files that we access via memory mapping in >> >> >> Java. Someone's asked us about how to make this conveniently >> >> >> deployable in Hadoop. If we tell them to put the files into hdfs, >> >> >> can >> >> >> we obtain a File for the underlying file on any given node? >> >> >> >> >> > >> >> >> >> This features it not yet part of hadoop so doing this is not >> >> "convenient". >> > >> > > >
