ql/src/test/queries/clientpositive/union_remove_3.q

set hive.mapred.mode=nonstrict;
set hive.stats.autogather=false;
set hive.optimize.union.remove=true;

set hive.merge.mapfiles=false;
set hive.merge.mapredfiles=false;

-- SORT_QUERY_RESULTS
-- This is to test the union->remove->filesink optimization
-- Union of 3 subqueries is performed (all of which are map-only queries)
-- followed by select star and a file sink.
-- There is no need for any optimization, since the whole query can be processed in
-- a single map-only job
-- It does not matter, whether the output is merged or not. In this case, merging is turned
-- off
-- Since this test creates sub-directories for the output table outputTbl1_n23, it might be easier
-- to run the test only on hadoop 23

create table inputTbl1_n16(key string, val string) stored as textfile;
create table outputTbl1_n23(key string, `values` bigint) stored as textfile;

load data local inpath '../../data/files/T1.txt' into table inputTbl1_n16;

explain
insert overwrite table outputTbl1_n23
SELECT *
FROM (
  SELECT key, 1 as `values` from inputTbl1_n16
  UNION ALL
  SELECT key, 2 as `values` from inputTbl1_n16
  UNION ALL
  SELECT key, 3 as `values` from inputTbl1_n16
) a;

insert overwrite table outputTbl1_n23
SELECT *
FROM (
  SELECT key, 1 as `values` from inputTbl1_n16
  UNION ALL
  SELECT key, 2 as `values` from inputTbl1_n16
  UNION ALL
  SELECT key, 3 as `values` from inputTbl1_n16
) a;

desc formatted outputTbl1_n23;

set hive.input.format=org.apache.hadoop.hive.ql.io.HiveInputFormat;
select * from outputTbl1_n23;