Map output files, by which you perhaps mean intermediate data files for temporary K/V persistence, are stored in IFiles. They do not use text nor sequence files (historically though, they did use sequence files at some point).
You can read the IFile's sources at http://svn.apache.org/repos/asf/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/IFile.java for more technical details on it. It is very similar to SequenceFiles in some ways. On Fri, Dec 14, 2012 at 12:45 PM, Pedro Sá da Costa <psdc1...@gmail.com> wrote: > Hi, > > There only 2 types of map output files, Sequence and Text files. If > those files are going to be used as input to several reduce tasks, > they need to be partitioned into blocks. Is there any SEPARATOR bits > that limits each partition? Can I read a specific partition of a map > output file? Is there an API for that? > > -- > Best regards, -- Harsh J
