--! qt:transactional

set hive.optimize.bi.enabled=true;

create table sketch_input (id int, category char(1))
STORED AS ORC
TBLPROPERTIES ('transactional'='true');

insert into table sketch_input values
  (1,'a'),(1, 'a'), (2, 'a'), (3, 'a'), (4, 'a'), (5, 'a'), (6, 'a'), (7, 'a'), (8, 'a'), (9, 'a'), (10, 'a'),
  (6,'b'),(6, 'b'), (7, 'b'), (8, 'b'), (9, 'b'), (10, 'b'), (11, 'b'), (12, 'b'), (13, 'b'), (14, 'b'), (15, 'b')
; 

-- see if rewrite happens
explain
select category, count(distinct id) from sketch_input group by category;

select category, count(distinct id) from sketch_input group by category;