if you look closely in first phase it executes your transform and in second
it does your sum operation
On Wed, Jan 23, 2013 at 11:24 AM, Richard wrote:
> thanks. I used explain command and get the plan, but I am still confused.
> The below is the description of two map-reduce stages:
>
> it see
you can run explain extended (your query) to get more details
On Wed, Jan 23, 2013 at 9:15 AM, Richard wrote:
> I am wondering how to determine the number of map-reduce for a hive query.
>
> for example, the following query
>
> select
> sum(c1),
> sum(c2),
> k1
> from
> {
> select transform(*
I am wondering how to determine the number of map-reduce for a hive query.
for example, the following query
select
sum(c1),
sum(c2),
k1
from
{
select transform(*) using 'mymapper' as c1, c2, k1
from t1
} a group by k1;
when i run this query, it takes two map-reduce, but I expect it to take