我有分区表,表结构
create table tab1
(
col1 int,
col2 string,
...
col50 int,
col51 int
)
partitioned by
(col50 int, col51 int)
stored as orc;
目前我们有大约 17000 个分区,每个分区至少有大约 50k 条记录。
下面的查询需要更多时间 ~ 90Mins
SELECT DISTINCT col2 FROM tab1
select col2 from (select col2, row_number() over (partition by col2 order by col3) as rnk from tab1) t1 where t1.rnk=1
有没有办法可以减少执行时间,提前谢谢