title: How to merge small files created by hive while inserting data into buckets?
body: <p>I have a hive table which contains call data records(CDRs). I have the table partitioned on the phone number and bucketed on call_date. Now when I am inserting data into hive the back dated call_date are creating small files in my buckets which is creating name node metadata increase and performance slowdown.
  Is there a way to merge these small files into one.</p>