Hive python self-defined udf function error

add file /home/sdev/yanan/udf.py;
select TRANSFORM (news_entry_id)
USING 'python udf.py' 
AS (comb)
 from tmp.yanan_gbdt
where p_date='20180708'
limit 10
;

I have defined a function to process the field of news_entry_id. The tmp.yanan_gbdt table take the p_date as partition. The codes works well.

But if I get rid of this condition where p_date='20180708' that I do not specify the partition, there comes the error: FAILED: NullPointerException null So what's wrong with this ?