[HIVE-4136] hive should optimize the scenario when the input and output are bucketed/sorted on the same keys

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Query Processor
• Assignee: Unassigned
• Reporter: Namit Jain
• Created: 07/Mar/13 16:45
• Updated: 07/Mar/13 16:45

Description

Consider a common scenario like:

create table T1 (...) clustered by (key) sorted by (key) into 2 buckets;
create table T2 (...) clustered by (key) sorted by (key) into 2 buckets;

SET hive.enforce.sorting=true;
SET hive.enforce.bucketing=true;

insert overwrite table T2
select * from T1;

The above query creates a reducer to make sure T2 is bucketed/sorted.
That is not needed