title: How to safely update hive external table
body: <p>I have an external hive table and I would like to refresh the data files on a daily basis. What is the recommended way to do this?</p>
  
  <p>If I just overwrite the files, and if we are unlucky enough to have some other hive queries to execute in parallel against this table, what will happen to those queries? Will they just fail? Or will my HDFS operations fail? Or will they block until the queries complete?</p>