Benefit of ORC format storing Sum, Min, Max...

[sreejesh s]

Hi,
I am new to Hive, please help me understand the benefit of ORC file format 
storing Sum, Min, Max values.Whenever we try to find a sum of values in a 
particular column, it still runs the MapReduce job.
select sum(col1) from orctable;select sum(col1) from txttable;
For a sample file with around 100 records, i dint see any difference in 
performance running the above queries .. Please let me know what am i missing...

Thanks