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Posted to dev@hive.apache.org by "Pavan Srinivas (JIRA)" <ji...@apache.org> on 2015/02/23 20:25:11 UTC
[jira] [Created] (HIVE-9753) Wrong results when using multiple
levels of Joins. When table alias of one of the table is null with left
outer joins.
Pavan Srinivas created HIVE-9753:
------------------------------------
Summary: Wrong results when using multiple levels of Joins. When table alias of one of the table is null with left outer joins.
Key: HIVE-9753
URL: https://issues.apache.org/jira/browse/HIVE-9753
Project: Hive
Issue Type: Bug
Reporter: Pavan Srinivas
Priority: Critical
Let take scenario, where the tables are:
{code}
drop table table1;
CREATE TABLE table1(
col1 string,
col2 string,
col3 string,
col4 string
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
STORED AS INPUTFORMAT
'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat';
drop table table2;
CREATE TABLE table2(
col1 string,
col2 bigint,
col3 string,
col4 string
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
STORED AS INPUTFORMAT
'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat';
drop table table3;
CREATE TABLE table3(
col1 string,
col2 int,
col3 int,
col4 string)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
STORED AS INPUTFORMAT
'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat';
{code}
Query with wrong results:
{code}
SELECT t1.col1 AS dummy,
t1.expected_column AS expected_column,
t2.col4
FROM (
SELECT col1,
'23-11111',
'23-13' as three,
col4 AS expected_column
FROM table1
) t1
JOIN table2 t2
ON cast(t2.col1 as string) = cast(t1.col1 as string)
LEFT OUTER JOIN
(SELECT col4, col1
FROM table3
) t3
ON t2.col4 = t3.col1
;
{code}
and explain output:
{code}
STAGE DEPENDENCIES:
Stage-7 is a root stage
Stage-5 depends on stages: Stage-7
Stage-0 depends on stages: Stage-5
STAGE PLANS:
Stage: Stage-7
Map Reduce Local Work
Alias -> Map Local Tables:
t1:table1
Fetch Operator
limit: -1
t3:table3
Fetch Operator
limit: -1
Alias -> Map Local Operator Tree:
t1:table1
TableScan
alias: table1
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Filter Operator
predicate: col1 is not null (type: boolean)
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: col1 (type: string)
outputColumnNames: _col0
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
HashTable Sink Operator
condition expressions:
0
1 {col4}
keys:
0 _col0 (type: string)
1 col1 (type: string)
t3:table3
TableScan
alias: table3
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: col1 (type: string)
outputColumnNames: _col1
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
HashTable Sink Operator
condition expressions:
0 {_col0} {_col7} {_col7}
1
keys:
0 _col7 (type: string)
1 _col1 (type: string)
Stage: Stage-5
Map Reduce
Map Operator Tree:
TableScan
alias: t2
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Filter Operator
predicate: col1 is not null (type: boolean)
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Map Join Operator
condition map:
Inner Join 0 to 1
condition expressions:
0 {_col0}
1 {col4}
keys:
0 _col0 (type: string)
1 col1 (type: string)
outputColumnNames: _col0, _col7
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Map Join Operator
condition map:
Left Outer Join0 to 1
condition expressions:
0 {_col0} {_col7} {_col7}
1
keys:
0 _col7 (type: string)
1 _col1 (type: string)
outputColumnNames: _col0, _col3, _col7
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: _col0 (type: string), _col3 (type: string), _col7 (type: string)
outputColumnNames: _col0, _col1, _col2
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
Local Work:
Map Reduce Local Work
Stage: Stage-0
Fetch Operator
limit: -1
Processor Tree:
ListSink
{code}
After the patch, explain output(correct)
{code}
STAGE DEPENDENCIES:
Stage-7 is a root stage
Stage-5 depends on stages: Stage-7
Stage-0 depends on stages: Stage-5
STAGE PLANS:
Stage: Stage-7
Map Reduce Local Work
Alias -> Map Local Tables:
t1:table1
Fetch Operator
limit: -1
t3:table3
Fetch Operator
limit: -1
Alias -> Map Local Operator Tree:
t1:table1
TableScan
alias: table1
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Filter Operator
predicate: col1 is not null (type: boolean)
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: col1 (type: string), col4 (type: string)
outputColumnNames: _col0, _col3
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
HashTable Sink Operator
condition expressions:
0 {_col3}
1 {col4}
keys:
0 _col0 (type: string)
1 col1 (type: string)
t3:table3
TableScan
alias: table3
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: col1 (type: string)
outputColumnNames: _col1
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
HashTable Sink Operator
condition expressions:
0 {_col0} {_col3} {_col7}
1
keys:
0 _col7 (type: string)
1 _col1 (type: string)
Stage: Stage-5
Map Reduce
Map Operator Tree:
TableScan
alias: t2
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Filter Operator
predicate: col1 is not null (type: boolean)
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Map Join Operator
condition map:
Inner Join 0 to 1
condition expressions:
0 {_col0} {_col3}
1 {col4}
keys:
0 _col0 (type: string)
1 col1 (type: string)
outputColumnNames: _col0, _col3, _col7
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Map Join Operator
condition map:
Left Outer Join0 to 1
condition expressions:
0 {_col0} {_col3} {_col7}
1
keys:
0 _col7 (type: string)
1 _col1 (type: string)
outputColumnNames: _col0, _col3, _col7
Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE
Select Operator
expressions: _col0 (type: string), _col3 (type: string), _col7 (type: string)
outputColumnNames: _col0, _col1, _col2
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
Local Work:
Map Reduce Local Work
Stage: Stage-0
Fetch Operator
limit: -1
Processor Tree:
ListSink
{code}
Notice the difference of "_col3" between the two explain outputs.
Output of the query:(WRONG)
{code}
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
one bad_data_1 bad_data_1
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
two bad_data_2 bad_data_2
{code}
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