map only job returns empty file and union all

[Guy Doulberg]

Hi guys

I have an issue with union all empty files and map-only job
I have a union all with two queries on of the quires  is a simple select 
(no reducers) on a partitioned table that returns 101 files, the last 
file is empty...


When the next step of the union all is executed the job fails because of 
EOFException in the map task.

So the questions I have are:
1. Why empty files are created anyways, and how can I prevent them from 
happening?
2. Why the map fails with EOFException on an empty file.

I would add that I am running on hive 0.9.0-CDH4.1.3,

and that this query ran okay on hive 0.7.0

Thanks

Guy Doulberg