dima machlin created HIVE-7205:
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Summary: Wrong results when union all of grouping followed by
group by with correlation optimization
Key: HIVE-7205
URL: https://issues.apache.org/jira/browse/HIVE-7205
Project: Hive
Issue Type: Bug
Affects Versions: 0.12.0
Reporter: dima machlin
Priority: Critical
use case :
table TBL (a string,b string) contains single row : 'a','a'
the following query :
select b, sum(cc) from (
select b,count(1) as cc from TBL group by b
union all
select a as b,count(1) as cc from TBL group by a
) z
group by b
returns
a 1
a 1
while set hive.optimize.correlation=true;
if we change set hive.optimize.correlation=false;
it returns correct results : a 2
The plan with correlation optimization :
ABSTRACT SYNTAX TREE:
(TOK_QUERY (TOK_FROM (TOK_SUBQUERY (TOK_UNION (TOK_QUERY (TOK_FROM
(TOK_TABREF (TOK_TABNAME DB TBL))) (TOK_INSERT (TOK_DESTINATION (TOK_DIR
TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_TABLE_OR_COL b)) (TOK_SELEXPR
(TOK_FUNCTION count 1) cc)) (TOK_GROUPBY (TOK_TABLE_OR_COL b)))) (TOK_QUERY
(TOK_FROM (TOK_TABREF (TOK_TABNAME DB TBL))) (TOK_INSERT (TOK_DESTINATION
(TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_TABLE_OR_COL a) b)
(TOK_SELEXPR (TOK_FUNCTION count 1) cc)) (TOK_GROUPBY (TOK_TABLE_OR_COL a)))))
z)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT
(TOK_SELEXPR (TOK_TABLE_OR_COL b)) (TOK_SELEXPR (TOK_FUNCTION sum
(TOK_TABLE_OR_COL cc)))) (TOK_GROUPBY (TOK_TABLE_OR_COL b))))
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:z-subquery1:TBL
TableScan
alias: TBL
Select Operator
expressions:
expr: b
type: string
outputColumnNames: b
Group By Operator
aggregations:
expr: count(1)
bucketGroup: false
keys:
expr: b
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: 0
value expressions:
expr: _col1
type: bigint
null-subquery2:z-subquery2:TBL
TableScan
alias: TBL
Select Operator
expressions:
expr: a
type: string
outputColumnNames: a
Group By Operator
aggregations:
expr: count(1)
bucketGroup: false
keys:
expr: a
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: 1
value expressions:
expr: _col1
type: bigint
Reduce Operator Tree:
Demux Operator
Group By Operator
aggregations:
expr: count(VALUE._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: string
mode: mergepartial
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Union
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Mux Operator
Group By Operator
aggregations:
expr: sum(_col1)
bucketGroup: false
keys:
expr: _col0
type: string
mode: complete
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
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
Group By Operator
aggregations:
expr: count(VALUE._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: string
mode: mergepartial
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Union
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Mux Operator
Group By Operator
aggregations:
expr: sum(_col1)
bucketGroup: false
keys:
expr: _col0
type: string
mode: complete
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
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
Plan without correlation optimization :
ABSTRACT SYNTAX TREE:
(TOK_QUERY (TOK_FROM (TOK_SUBQUERY (TOK_UNION (TOK_QUERY (TOK_FROM
(TOK_TABREF (TOK_TABNAME DB TBL))) (TOK_INSERT (TOK_DESTINATION (TOK_DIR
TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_TABLE_OR_COL b)) (TOK_SELEXPR
(TOK_FUNCTION count 1) cc)) (TOK_GROUPBY (TOK_TABLE_OR_COL b)))) (TOK_QUERY
(TOK_FROM (TOK_TABREF (TOK_TABNAME DB TBL))) (TOK_INSERT (TOK_DESTINATION
(TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR (TOK_TABLE_OR_COL a) b)
(TOK_SELEXPR (TOK_FUNCTION count 1) cc)) (TOK_GROUPBY (TOK_TABLE_OR_COL a)))))
z)) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT
(TOK_SELEXPR (TOK_TABLE_OR_COL b)) (TOK_SELEXPR (TOK_FUNCTION sum
(TOK_TABLE_OR_COL cc)))) (TOK_GROUPBY (TOK_TABLE_OR_COL b))))
STAGE DEPENDENCIES:
Stage-1 is a root stage
Stage-2 depends on stages: Stage-1, Stage-3
Stage-3 is a root stage
Stage-0 is a root stage
STAGE PLANS:
Stage: Stage-1
Map Reduce
Alias -> Map Operator Tree:
null-subquery2:z-subquery2:TBL
TableScan
alias: TBL
Select Operator
expressions:
expr: a
type: string
outputColumnNames: a
Group By Operator
aggregations:
expr: count(1)
bucketGroup: false
keys:
expr: a
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: -1
value expressions:
expr: _col1
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: string
mode: mergepartial
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
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:
maprfs:/user/hadoop/tmp/hive/hive_2014-06-10_15-42-37_188_2403850033480056671-5/-mr-10002
TableScan
Union
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Group By Operator
aggregations:
expr: sum(_col1)
bucketGroup: false
keys:
expr: _col0
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: -1
value expressions:
expr: _col1
type: bigint
maprfs:/user/hadoop/tmp/hive/hive_2014-06-10_15-42-37_188_2403850033480056671-5/-mr-10003
TableScan
Union
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
Group By Operator
aggregations:
expr: sum(_col1)
bucketGroup: false
keys:
expr: _col0
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: -1
value expressions:
expr: _col1
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: sum(VALUE._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: string
mode: mergepartial
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
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-3
Map Reduce
Alias -> Map Operator Tree:
null-subquery1:z-subquery1:TBL
TableScan
alias: TBL
Select Operator
expressions:
expr: b
type: string
outputColumnNames: b
Group By Operator
aggregations:
expr: count(1)
bucketGroup: false
keys:
expr: b
type: string
mode: hash
outputColumnNames: _col0, _col1
Reduce Output Operator
key expressions:
expr: _col0
type: string
sort order: +
Map-reduce partition columns:
expr: _col0
type: string
tag: -1
value expressions:
expr: _col1
type: bigint
Reduce Operator Tree:
Group By Operator
aggregations:
expr: count(VALUE._col0)
bucketGroup: false
keys:
expr: KEY._col0
type: string
mode: mergepartial
outputColumnNames: _col0, _col1
Select Operator
expressions:
expr: _col0
type: string
expr: _col1
type: bigint
outputColumnNames: _col0, _col1
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-0
Fetch Operator
limit: -1
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