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Posted to issues@hive.apache.org by "Janaki Lahorani (JIRA)" <ji...@apache.org> on 2018/09/17 02:03:00 UTC
[jira] [Assigned] (HIVE-20570) Union ALL with
hive.optimize.union.remove=true has incorrect plan
[ https://issues.apache.org/jira/browse/HIVE-20570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Janaki Lahorani reassigned HIVE-20570:
--------------------------------------
Assignee: Janaki Lahorani
> Union ALL with hive.optimize.union.remove=true has incorrect plan
> -----------------------------------------------------------------
>
> Key: HIVE-20570
> URL: https://issues.apache.org/jira/browse/HIVE-20570
> Project: Hive
> Issue Type: Bug
> Reporter: Janaki Lahorani
> Assignee: Janaki Lahorani
> Priority: Major
>
> When hive.optimize.union.remove=true and a select query is run with group by, the final fetch is waiting only for one of the branches and not both.
> Test Case:
> {code}
> create table if not exists test_table(column1 string, column2 int);
> insert into test_table values('a',1),('b',2);
> set hive.optimize.union.remove=true;
> set mapred.input.dir.recursive=true;
> explain
> select column1 from test_table group by column1
> union all
> select column1 from test_table group by column1;
> {code}
> In the below the two stages correspond to the two parts of union all. But the final fetch operator (Stage 0) only depends on one of the stages, but it should depend on both.
> Plan:
> {code}
> STAGE DEPENDENCIES:
> Stage-1 is a root stage
> Stage-2 is a root stage
> * Stage-0 depends on stages: Stage-1*
> STAGE PLANS:
> Stage: Stage-1
> Map Reduce
> Map Operator Tree:
> TableScan
> alias: test_table
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Select Operator
> expressions: column1 (type: string)
> outputColumnNames: column1
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Group By Operator
> keys: column1 (type: string)
> mode: hash
> outputColumnNames: _col0
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Reduce Output Operator
> key expressions: _col0 (type: string)
> sort order: +
> Map-reduce partition columns: _col0 (type: string)
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Execution mode: vectorized
> Reduce Operator Tree:
> Group By Operator
> keys: KEY._col0 (type: string)
> mode: mergepartial
> outputColumnNames: _col0
> Statistics: Num rows: 1 Data size: 3 Basic stats: COMPLETE Column stats: NONE
> File Output Operator
> compressed: false
> Statistics: Num rows: 1 Data size: 3 Basic stats: COMPLETE Column stats: NONE
> table:
> input format: org.apache.hadoop.mapred.SequenceFileInputFormat
> output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
> serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
> Stage: Stage-2
> Map Reduce
> Map Operator Tree:
> TableScan
> alias: test_table
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Select Operator
> expressions: column1 (type: string)
> outputColumnNames: column1
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Group By Operator
> keys: column1 (type: string)
> mode: hash
> outputColumnNames: _col0
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Reduce Output Operator
> key expressions: _col0 (type: string)
> sort order: +
> Map-reduce partition columns: _col0 (type: string)
> Statistics: Num rows: 2 Data size: 6 Basic stats: COMPLETE Column stats: NONE
> Execution mode: vectorized
> Reduce Operator Tree:
> Group By Operator
> keys: KEY._col0 (type: string)
> mode: mergepartial
> outputColumnNames: _col0
> Statistics: Num rows: 1 Data size: 3 Basic stats: COMPLETE Column stats: NONE
> File Output Operator
> compressed: false
> Statistics: Num rows: 1 Data size: 3 Basic stats: COMPLETE Column stats: NONE
> table:
> input format: org.apache.hadoop.mapred.SequenceFileInputFormat
> output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
> serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
> Stage: Stage-0
> Fetch Operator
> limit: -1
> Processor Tree:
> ListSink
> {code}
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