title: Hadoop gzip input file using only one mapper
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/6511255/why-cant-hadoop-split-up-a-large-text-file-and-then-compress-the-splits-using-gz">Why can&#39;t hadoop split up a large text file and then compress the splits using gzip?</a>  </p>
  </blockquote>
  
  
  
  <p>I found that when using input file that is gzipped the Hadoop chooses to allocate only one map task to handle my map/reduce job.</p>
  
  <p>The gzipped file is more than 1.4 GB, so I would expect many mappers to run in parallel (exacly like when using un-zipped file)</p>
  
  <p>Is there any configuration I can do to improve it? </p>