PREHOOK: query: -- HIVE-3464

create table a (key string, value string)
PREHOOK: type: CREATETABLE
PREHOOK: Output: database:default
PREHOOK: Output: default@a
POSTHOOK: query: -- HIVE-3464

create table a (key string, value string)
POSTHOOK: type: CREATETABLE
POSTHOOK: Output: database:default
POSTHOOK: Output: default@a
PREHOOK: query: -- (a-b-c-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.key=c.key) left outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: -- (a-b-c-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.key=c.key) left outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Left Outer Join1 to 2
               Left Outer Join0 to 3
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
            3 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.key=c.key) right outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.key=c.key) right outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Left Outer Join1 to 2
               Right Outer Join0 to 3
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
            3 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.key=c.key) left outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.key=c.key) left outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Right Outer Join1 to 2
               Left Outer Join0 to 3
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
            3 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.key=c.key) right outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.key=c.key) right outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Right Outer Join1 to 2
               Right Outer Join0 to 3
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
            3 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: -- ((a-b-d)-c) (reordered)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) left outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: -- ((a-b-d)-c) (reordered)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) left outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-0 depends on stages: Stage-2

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Left Outer Join0 to 2
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Left Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col15 (type: string), _col16 (type: string), _col10 (type: string), _col11 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) right outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) right outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-0 depends on stages: Stage-2

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Right Outer Join0 to 2
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Right Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col15 (type: string), _col16 (type: string), _col10 (type: string), _col11 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) full outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) full outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-0 depends on stages: Stage-2

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
               Outer Join 0 to 2
          keys:
            0 key (type: string)
            1 key (type: string)
            2 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Outer Join 0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col15 (type: string), _col16 (type: string), _col10 (type: string), _col11 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: -- (((a-b)-c)-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) right outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: -- (((a-b)-c)-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) right outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-3 depends on stages: Stage-2
  Stage-0 depends on stages: Stage-3

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          keys:
            0 key (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Left Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-3
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col0 (type: string)
              sort order: +
              Map-reduce partition columns: _col0 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Right Outer Join0 to 1
          keys:
            0 _col0 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-3 depends on stages: Stage-2
  Stage-0 depends on stages: Stage-3

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          keys:
            0 key (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Left Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-3
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col0 (type: string)
              sort order: +
              Map-reduce partition columns: _col0 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Outer Join 0 to 1
          keys:
            0 _col0 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) left outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) left outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-3 depends on stages: Stage-2
  Stage-0 depends on stages: Stage-3

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          keys:
            0 key (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Right Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-3
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col0 (type: string)
              sort order: +
              Map-reduce partition columns: _col0 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Left Outer Join0 to 1
          keys:
            0 _col0 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: explain
select * from a join a b on (a.key=b.key) right outer join a c on (b.value=c.key) full outer join a d on (a.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-3 depends on stages: Stage-2
  Stage-0 depends on stages: Stage-3

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          keys:
            0 key (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Right Outer Join0 to 1
          keys:
            0 _col6 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-3
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col0 (type: string)
              sort order: +
              Map-reduce partition columns: _col0 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Outer Join 0 to 1
          keys:
            0 _col0 (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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

PREHOOK: query: -- ((a-b)-c-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) left outer join a d on (c.key=d.key)
PREHOOK: type: QUERY
POSTHOOK: query: -- ((a-b)-c-d)
explain
select * from a join a b on (a.key=b.key) left outer join a c on (b.value=c.key) left outer join a d on (c.key=d.key)
POSTHOOK: type: QUERY
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-2 depends on stages: Stage-1
  Stage-0 depends on stages: Stage-2

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Map Operator Tree:
          TableScan
            alias: a
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
          TableScan
            alias: b
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Filter Operator
              predicate: key is not null (type: boolean)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              Reduce Output Operator
                key expressions: key (type: string)
                sort order: +
                Map-reduce partition columns: key (type: string)
                Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
                value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          keys:
            0 key (type: string)
            1 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          File Output Operator
            compressed: false
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
                serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe

  Stage: Stage-2
    Map Reduce
      Map Operator Tree:
          TableScan
            Reduce Output Operator
              key expressions: _col6 (type: string)
              sort order: +
              Map-reduce partition columns: _col6 (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string)
          TableScan
            alias: c
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
          TableScan
            alias: d
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            Reduce Output Operator
              key expressions: key (type: string)
              sort order: +
              Map-reduce partition columns: key (type: string)
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
              value expressions: value (type: string)
      Reduce Operator Tree:
        Join Operator
          condition map:
               Left Outer Join0 to 1
               Left Outer Join1 to 2
          keys:
            0 _col6 (type: string)
            1 key (type: string)
            2 key (type: string)
          outputColumnNames: _col0, _col1, _col5, _col6, _col10, _col11, _col15, _col16
          Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
          Select Operator
            expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string), _col10 (type: string), _col11 (type: string), _col15 (type: string), _col16 (type: string)
            outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, _col6, _col7
            Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
            File Output Operator
              compressed: false
              Statistics: Num rows: 0 Data size: 0 Basic stats: NONE 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