explain_plan_tez

Explain
Plan optimized by CBO.

Vertex dependency in root stage
Map 1 <- Union 2 (CONTAINS)
Map 4 <- Union 2 (CONTAINS)
Map 5 <- Union 2 (CONTAINS)
Map 6 <- Union 2 (CONTAINS)
Reducer 3 <- Union 2 (SIMPLE_EDGE)

Stage-3
  Stats-Aggr Operator
    Stage-0
      Move Operator
        table:{"name:":"test.test_tez_multiunion"}
        Stage-2
          Dependency Collection{}
            Stage-1
              Reducer 3
              File Output Operator [FS_22]
                table:{"name:":"test.test_tez_multiunion"}
                Select Operator [SEL_20] (rows=2181035216 width=131)
                  Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"]
                  Group By Operator [GBY_19] (rows=2181035216 width=131)
                    Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"],aggregations:["count(DISTINCT KEY._col5:0._col0)","count(DISTINCT KEY._col5:1._col0)"],keys:KEY._col0, KEY._col1, KEY._col2, KEY._col3, KEY._col4
                  <-Union 2 [SIMPLE_EDGE]
                    <-Map 1 [CONTAINS]
                      Reduce Output Operator [RS_18]
                        PartitionCols:_col0, _col1, _col2, _col3, _col4
                        Group By Operator [GBY_17] (rows=4362070432 width=131)
                          Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6","_col7","_col8"],aggregations:["count(DISTINCT _col0)","count(DISTINCT _col6)"],keys:_col1, _col2, _col3, _col4, _col5, _col0, _col6
                          Select Operator [SEL_2] (rows=1090517608 width=131)
                            Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"]
                            Filter Operator [FIL_23] (rows=1090517608 width=131)
                              predicate:((to_date(start_date_time) <= 2016-11-20) and ((to_date(end_date_time) > 2016-11-20) or end_date_time is null))
                              TableScan [TS_0] (rows=3925863392 width=131)
                                Output:["l_id","psla","fsp","lis","aver","asub","iid","start_date_time","end_date_time"]
                    <-Map 4 [CONTAINS]
                      Reduce Output Operator [RS_18]
                        PartitionCols:_col0, _col1, _col2, _col3, _col4
                        Group By Operator [GBY_17] (rows=4362070432 width=131)
                          Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6","_col7","_col8"],aggregations:["count(DISTINCT _col0)","count(DISTINCT _col6)"],keys:_col1, _col2, _col3, _col4, _col5, _col0, _col6
                          Select Operator [SEL_5] (rows=1090517608 width=131)
                            Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"]
                            Filter Operator [FIL_24] (rows=1090517608 width=131)
                              predicate:((to_date(start_date_time) <= 2016-11-20) and ((to_date(end_date_time) > 2016-11-20) or end_date_time is null))
                              TableScan [TS_3] (rows=3925863392 width=131)
                                Output:["l_id","psla","fsp","lis","aver","asub","iid","start_date_time","end_date_time"]
                    <-Map 5 [CONTAINS]
                      Reduce Output Operator [RS_18]
                        PartitionCols:_col0, _col1, _col2, _col3, _col4
                        Group By Operator [GBY_17] (rows=4362070432 width=131)
                          Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6","_col7","_col8"],aggregations:["count(DISTINCT _col0)","count(DISTINCT _col6)"],keys:_col1, _col2, _col3, _col4, _col5, _col0, _col6
                          Select Operator [SEL_10] (rows=1090517608 width=131)
                            Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"]
                            Filter Operator [FIL_25] (rows=1090517608 width=131)
                              predicate:((to_date(start_date_time) <= 2016-11-20) and ((to_date(end_date_time) > 2016-11-20) or end_date_time is null))
                              TableScan [TS_8] (rows=3925863392 width=131)
                                Output:["l_id","psla","fsp","lis","aver","asub","iid","start_date_time","end_date_time"]
                    <-Map 6 [CONTAINS]
                      Reduce Output Operator [RS_18]
                        PartitionCols:_col0, _col1, _col2, _col3, _col4
                        Group By Operator [GBY_17] (rows=4362070432 width=131)
                          Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6","_col7","_col8"],aggregations:["count(DISTINCT _col0)","count(DISTINCT _col6)"],keys:_col1, _col2, _col3, _col4, _col5, _col0, _col6
                          Select Operator [SEL_14] (rows=1090517608 width=131)
                            Output:["_col0","_col1","_col2","_col3","_col4","_col5","_col6"]
                            Filter Operator [FIL_26] (rows=1090517608 width=131)
                              predicate:((to_date(start_date_time) <= 2016-11-20) and ((to_date(end_date_time) > 2016-11-20) or end_date_time is null))
                              TableScan [TS_12] (rows=3925863392 width=131)
                                Output:["l_id","psla","fsp","lis","aver","asub","iid","start_date_time","end_date_time"]