set hive.optimize.bucketmapjoin = true; set hive.optimize.bucketmapjoin.sortedmerge = true; set hive.enforce.bucketing=true; set hive.enforce.sorting=true; set hive.exec.reducers.max = 1; set hive.merge.mapfiles=false; set hive.merge.mapredfiles=false; set hive.auto.convert.sortmerge.join.to.mapjoin=true; -- Create two bucketed and sorted tables CREATE TABLE test_table1 (key INT, value STRING) PARTITIONED BY (ds STRING) CLUSTERED BY (key) SORTED BY (key) INTO 2 BUCKETS; CREATE TABLE test_table2 (value STRING, key INT) PARTITIONED BY (ds STRING) CLUSTERED BY (key) SORTED BY (key) INTO 2 BUCKETS; FROM src INSERT OVERWRITE TABLE test_table1 PARTITION (ds = '1') SELECT *; -- Insert data into the bucketed table by selecting from another bucketed table -- The bucketing positions dont match - although the actual bucketing do. -- This should be a map-only operation EXPLAIN INSERT OVERWRITE TABLE test_table2 PARTITION (ds = '1') SELECT x.value, x.key from (SELECT a.key, a.value FROM test_table1 a WHERE a.ds = '1')x; INSERT OVERWRITE TABLE test_table2 PARTITION (ds = '1') SELECT x.value, x.key from (SELECT a.key, a.value FROM test_table1 a WHERE a.ds = '1')x; select count(*) from test_table2 where ds = '1'; select count(*) from test_table2 tablesample (bucket 1 out of 2) s where ds = '1'; select count(*) from test_table2 tablesample (bucket 2 out of 2) s where ds = '1'; CREATE TABLE test_table3 (key INT, value STRING) PARTITIONED BY (ds STRING) CLUSTERED BY (value) SORTED BY (value) INTO 2 BUCKETS; -- Insert data into the bucketed table by selecting from another bucketed table -- The bucketing positions dont match - this should be a map-reduce operation EXPLAIN INSERT OVERWRITE TABLE test_table2 PARTITION (ds = '1') SELECT x.key, x.value from (SELECT a.key, a.value FROM test_table1 a WHERE a.ds = '1')x; INSERT OVERWRITE TABLE test_table2 PARTITION (ds = '1') SELECT x.key, x.value from (SELECT a.key, a.value FROM test_table1 a WHERE a.ds = '1')x; select count(*) from test_table2 where ds = '1'; select count(*) from test_table2 tablesample (bucket 1 out of 2) s where ds = '1'; select count(*) from test_table2 tablesample (bucket 2 out of 2) s where ds = '1';