PREHOOK: query: -- SORT_BEFORE_DIFF -- union case: all subqueries are a map-only jobs, 3 way union, same input for all sub-queries, followed by reducesink explain select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION ALL select s2.key as key, s2.value as value from src s2 UNION ALL select s3.key as key, s3.value as value from src s3) unionsrc PREHOOK: type: QUERY POSTHOOK: query: -- SORT_BEFORE_DIFF -- union case: all subqueries are a map-only jobs, 3 way union, same input for all sub-queries, followed by reducesink explain select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION ALL select s2.key as key, s2.value as value from src s2 UNION ALL select s3.key as key, s3.value as value from src s3) unionsrc POSTHOOK: type: QUERY STAGE DEPENDENCIES: Stage-1 is a root stage Stage-0 depends on stages: Stage-1 STAGE PLANS: Stage: Stage-1 Tez Edges: Map 1 <- Union 2 (CONTAINS) Map 4 <- Union 2 (CONTAINS) Map 5 <- Union 2 (CONTAINS) Reducer 3 <- Union 2 (SIMPLE_EDGE) #### A masked pattern was here #### Vertices: Map 1 Map Operator Tree: TableScan alias: s1 Select Operator Select Operator Group By Operator aggregations: count(1) mode: hash outputColumnNames: _col0 Reduce Output Operator sort order: value expressions: _col0 (type: bigint) Map 4 Map Operator Tree: TableScan alias: s1 Select Operator Select Operator Group By Operator aggregations: count(1) mode: hash outputColumnNames: _col0 Reduce Output Operator sort order: value expressions: _col0 (type: bigint) Map 5 Map Operator Tree: TableScan alias: s1 Select Operator Select Operator Group By Operator aggregations: count(1) mode: hash outputColumnNames: _col0 Reduce Output Operator sort order: value expressions: _col0 (type: bigint) Reducer 3 Reduce Operator Tree: Group By Operator aggregations: count(VALUE._col0) mode: mergepartial outputColumnNames: _col0 Statistics: Num rows: 1 Data size: 8 Basic stats: COMPLETE Column stats: COMPLETE File Output Operator compressed: false Statistics: Num rows: 1 Data size: 8 Basic stats: COMPLETE Column stats: COMPLETE table: input format: org.apache.hadoop.mapred.TextInputFormat output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe Union 2 Vertex: Union 2 Stage: Stage-0 Fetch Operator limit: -1 Processor Tree: ListSink PREHOOK: query: select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION ALL select s2.key as key, s2.value as value from src s2 UNION ALL select s3.key as key, s3.value as value from src s3) unionsrc PREHOOK: type: QUERY PREHOOK: Input: default@src #### A masked pattern was here #### POSTHOOK: query: select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION ALL select s2.key as key, s2.value as value from src s2 UNION ALL select s3.key as key, s3.value as value from src s3) unionsrc POSTHOOK: type: QUERY POSTHOOK: Input: default@src #### A masked pattern was here #### 1500