bug (HIVE-15355) is being worked on by Hive engineering team at Hortonworks
You can use the following workaround :
1- use "SORT BY 0" at the end of the query which will force to use one reducer , please use this only if you have a small query.
2- try to use set hive.mv.files.thread=0; before running the query.
If you have any question regarding the above, please let me know.