hive> set hive.optimize.ppd=true;
hive> explain select a.* from a join b on(a.key=b.key) where a.some_col='blah';
OK
ABSTRACT SYNTAX TREE:
  (TOK_QUERY (TOK_FROM (TOK_JOIN (TOK_TABREF (TOK_TABNAME a)) (TOK_TABREF (TOK_TABNAME b)) (= (. (TOK_TABLE_OR_COL a) key) (. (TOK_TABLE_OR_COL b) key)))) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_ALLCOLREF (TOK_TABNAME a)))) (TOK_WHERE (= (. (TOK_TABLE_OR_COL a) some_col) 'blah'))))

STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 is a root stage

STAGE PLANS:
  Stage: Stage-1
    Map Reduce
      Alias -> Map Operator Tree:
        a
          TableScan
            alias: a
            Filter Operator
              predicate:
                  expr: (some_col = 'blah')
                  type: boolean
              Reduce Output Operator
                key expressions:
                      expr: key
                      type: int
                sort order: +
                Map-reduce partition columns:
                      expr: key
                      type: int
                tag: 0
                value expressions:
                      expr: key
                      type: int
                      expr: some_col
                      type: string
        b
          TableScan
            alias: b
            Reduce Output Operator
              key expressions:
                    expr: key
                    type: int
              sort order: +
              Map-reduce partition columns:
                    expr: key
                    type: int
              tag: 1
      Reduce Operator Tree:
        Join Operator
          condition map:
               Inner Join 0 to 1
          condition expressions:
            0 {VALUE._col0} {VALUE._col1}
            1
          handleSkewJoin: false
          outputColumnNames: _col0, _col1
          Filter Operator
            predicate:
                expr: (_col1 = 'blah')
                type: boolean
            Select Operator
              expressions:
                    expr: _col0
                    type: int
                    expr: _col1
                    type: string
              outputColumnNames: _col0, _col1
              File Output Operator
                compressed: false
                GlobalTableId: 0
                table:
                    input format: org.apache.hadoop.mapred.TextInputFormat
                    output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat

  Stage: Stage-0
    Fetch Operator
      limit: -1


Time taken: 2.659 seconds