query: CREATE TABLE dest1(c1 STRING) STORED AS TEXTFILE
query: EXPLAIN
FROM src
INSERT OVERWRITE TABLE dest1 SELECT substr(src.key,1,1) GROUP BY substr(src.key,1,1)
ABSTRACT SYNTAX TREE:
  (TOK_QUERY (TOK_FROM (TOK_TABREF src)) (TOK_INSERT (TOK_DESTINATION (TOK_TAB dest1)) (TOK_SELECT (TOK_SELEXPR (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL src) key) 1 1))) (TOK_GROUPBY (TOK_FUNCTION substr (. (TOK_TABLE_OR_COL src) key) 1 1))))

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
      Alias -> Map Operator Tree:
        src 
          TableScan
            alias: src
            Select Operator
              expressions:
                    expr: key
                    type: string
              outputColumnNames: key
              Reduce Output Operator
                key expressions:
                      expr: substr(key, 1, 1)
                      type: string
                sort order: +
                Map-reduce partition columns:
                      expr: rand()
                      type: double
                tag: -1
      Reduce Operator Tree:
        Group By Operator
          keys:
                expr: KEY._col0
                type: string
          mode: partial1
          outputColumnNames: _col0
          File Output Operator
            compressed: false
            GlobalTableId: 0
            table:
                input format: org.apache.hadoop.mapred.SequenceFileInputFormat
                output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat

  Stage: Stage-2
    Map Reduce
      Alias -> Map Operator Tree:
        file:/data/users/athusoo/commits/hive_trunk_ws1/build/ql/tmp/1357905866/10002 
            Reduce Output Operator
              key expressions:
                    expr: _col0
                    type: string
              sort order: +
              Map-reduce partition columns:
                    expr: _col0
                    type: string
              tag: -1
      Reduce Operator Tree:
        Group By Operator
          keys:
                expr: KEY._col0
                type: string
          mode: final
          outputColumnNames: _col0
          Select Operator
            expressions:
                  expr: _col0
                  type: string
            outputColumnNames: _col0
            File Output Operator
              compressed: false
              GlobalTableId: 1
              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
                  name: dest1

  Stage: Stage-0
    Move Operator
      tables:
          replace: true
          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
              name: dest1


query: FROM src
INSERT OVERWRITE TABLE dest1 SELECT substr(src.key,1,1) GROUP BY substr(src.key,1,1)
Input: default/src
Output: default/dest1
query: SELECT dest1.* FROM dest1
Input: default/dest1
Output: file:/data/users/athusoo/commits/hive_trunk_ws1/build/ql/tmp/1402842530/10000
0
1
2
3
4
5
6
7
8
9