Steps to reproduce:
- Go to Hive query editor
- Run "select * from sample_07"
- Choose from the download options export to HDFS.
- Choose option "All" but not "limit 100000" and enter a path like /user/hive/warehouse/customers
- Check /user/hive/warehouse/customers and see that the directory was purged and replaced with only data from sample_07.
Fix: When a user try to export query result to a non-empty directory, it will give a warning message "the destination is not an empty directory!"