Explain
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Tez
      Edges:
        Reducer 2 <- Map 1 (SIMPLE_EDGE)
      DagName: ubuntu_20151216204949_7f6d6241-4398-4b23-a1e6-707036e6a9c7:9
      Vertices:
        Map 1 
            Map Operator Tree:
                TableScan
                  alias: stage2_source
                  Statistics: Num rows: 20374920570 Data size: 40393482240 Basic stats: COMPLETE Column stats: NONE
                  Select Operator
                    expressions: emp_type (type: string), emp_id (type: string)
                    outputColumnNames: emp_type, emp_id
                    Statistics: Num rows: 20374920570 Data size: 40393482240 Basic stats: COMPLETE Column stats: NONE
                    Group By Operator
                      aggregations: count(DISTINCT emp_id)
                      keys: emp_type (type: string), emp_id (type: string)
                      mode: hash
                      outputColumnNames: _col0, _col1, _col2
                      Statistics: Num rows: 20374920570 Data size: 40393482240 Basic stats: COMPLETE Column stats: NONE
                      Reduce Output Operator
                        key expressions: _col0 (type: string), _col1 (type: string)
                        sort order: ++
                        Map-reduce partition columns: _col0 (type: string)
                        Statistics: Num rows: 20374920570 Data size: 40393482240 Basic stats: COMPLETE Column stats: NONE
            Execution mode: vectorized
        Reducer 2 
            Reduce Operator Tree:
              Group By Operator
                aggregations: count(DISTINCT KEY._col1:0._col0)
                keys: KEY._col0 (type: string)
                mode: mergepartial
                outputColumnNames: _col0, _col1
                Statistics: Num rows: 10187460285 Data size: 20196741120 Basic stats: COMPLETE Column stats: NONE
                Select Operator
                  expressions: _col0 (type: string), _col1 (type: bigint)
                  outputColumnNames: _col0, _col1
                  Statistics: Num rows: 10187460285 Data size: 20196741120 Basic stats: COMPLETE Column stats: NONE
                  File Output Operator
                    compressed: false
                    Statistics: Num rows: 10187460285 Data size: 20196741120 Basic stats: COMPLETE Column stats: NONE
                    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

  Stage: Stage-0
    Fetch Operator
      limit: -1
      Processor Tree:
        ListSink