hadoop - Hive always create mapreduce job -

i'm been using hive @ work, when run select

"select * tablename"  

hive executes mapreduce job , when run

"select * tablename limit x" independently of x.  

hive doesn't execute mapreduce jobs.

i use hive 1.2.1, hdp 2.3.0, hue 2.6.1 , hadoop 2.7.1

any ideas fact?

thanks!

select * table; 

requires no map nor reduce. there no filter(where statement) or aggregation function here. query reads hdfs.