| SET hive.optimize.topnkey=false; |
| |
| set tez.grouping.max-size=50; |
| set tez.grouping.min-size=25; |
| |
| create table test(id string); |
| |
| insert into test(id) values |
| (4), (3), (4), (3), (4), (3), (4), (3), (4), (3), (4), (3), (4), (3), (4), (3), (4), (3), (4), (2), (1), (5); |
| |
| explain cbo |
| select id, count(1) from test group by id limit 2; |
| explain extended |
| select id, count(1) from test group by id limit 2; |
| select id, count(1) from test group by id limit 2; |
| |
| SET hive.optimize.topnkey=true; |
| |
| explain extended |
| select id, count(1) from test group by id limit 2; |
| select id, count(1) from test group by id limit 2; |