Saving all output to "!!{outputDirectory}!!/union9.q.raw". Enter "record" with no arguments to stop it.
>>>  !run !!{qFileDirectory}!!/union9.q
>>>  -- union case: all subqueries are a map-only jobs, 3 way union, same input for all sub-queries, followed by reducesink
>>>  
>>>  explain 
select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION  ALL 
select s2.key as key, s2.value as value from src s2 UNION ALL 
select s3.key as key, s3.value as value from src s3) unionsrc;
'Explain'
'ABSTRACT SYNTAX TREE:'
'  (TOK_QUERY (TOK_FROM (TOK_SUBQUERY (TOK_UNION (TOK_UNION (TOK_QUERY (TOK_FROM (TOK_TABREF (TOK_TABNAME src) s1)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (. (TOK_TABLE_OR_COL s1) key) key) (TOK_SELEXPR (. (TOK_TABLE_OR_COL s1) value) value)))) (TOK_QUERY (TOK_FROM (TOK_TABREF (TOK_TABNAME src) s2)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (. (TOK_TABLE_OR_COL s2) key) key) (TOK_SELEXPR (. (TOK_TABLE_OR_COL s2) value) value))))) (TOK_QUERY (TOK_FROM (TOK_TABREF (TOK_TABNAME src) s3)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (. (TOK_TABLE_OR_COL s3) key) key) (TOK_SELEXPR (. (TOK_TABLE_OR_COL s3) value) value))))) unionsrc)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_FUNCTION count 1)))))'
''
'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:'
'        null-subquery1-subquery1:unionsrc-subquery1-subquery1:s1 '
'          TableScan'
'            alias: s1'
'            Select Operator'
'              expressions:'
'                    expr: key'
'                    type: string'
'                    expr: value'
'                    type: string'
'              outputColumnNames: _col0, _col1'
'              Union'
'                Select Operator'
'                  Group By Operator'
'                    aggregations:'
'                          expr: count(1)'
'                    bucketGroup: false'
'                    mode: hash'
'                    outputColumnNames: _col0'
'                    Reduce Output Operator'
'                      sort order: '
'                      tag: -1'
'                      value expressions:'
'                            expr: _col0'
'                            type: bigint'
'        null-subquery1-subquery2:unionsrc-subquery1-subquery2:s2 '
'          TableScan'
'            alias: s2'
'            Select Operator'
'              expressions:'
'                    expr: key'
'                    type: string'
'                    expr: value'
'                    type: string'
'              outputColumnNames: _col0, _col1'
'              Union'
'                Select Operator'
'                  Group By Operator'
'                    aggregations:'
'                          expr: count(1)'
'                    bucketGroup: false'
'                    mode: hash'
'                    outputColumnNames: _col0'
'                    Reduce Output Operator'
'                      sort order: '
'                      tag: -1'
'                      value expressions:'
'                            expr: _col0'
'                            type: bigint'
'        null-subquery2:unionsrc-subquery2:s3 '
'          TableScan'
'            alias: s3'
'            Select Operator'
'              expressions:'
'                    expr: key'
'                    type: string'
'                    expr: value'
'                    type: string'
'              outputColumnNames: _col0, _col1'
'              Union'
'                Select Operator'
'                  Group By Operator'
'                    aggregations:'
'                          expr: count(1)'
'                    bucketGroup: false'
'                    mode: hash'
'                    outputColumnNames: _col0'
'                    Reduce Output Operator'
'                      sort order: '
'                      tag: -1'
'                      value expressions:'
'                            expr: _col0'
'                            type: bigint'
'      Reduce Operator Tree:'
'        Group By Operator'
'          aggregations:'
'                expr: count(VALUE._col0)'
'          bucketGroup: false'
'          mode: mergepartial'
'          outputColumnNames: _col0'
'          Select Operator'
'            expressions:'
'                  expr: _col0'
'                  type: bigint'
'            outputColumnNames: _col0'
'            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'
''
''
107 rows selected 
>>>  
>>>  select count(1) FROM (select s1.key as key, s1.value as value from src s1 UNION  ALL 
select s2.key as key, s2.value as value from src s2 UNION ALL 
select s3.key as key, s3.value as value from src s3) unionsrc;
'_c0'
'1500'
1 row selected 
>>>  !record