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Posted to issues@hive.apache.org by "Krisztian Kasa (Jira)" <ji...@apache.org> on 2021/09/20 12:27:00 UTC

[jira] [Assigned] (HIVE-24579) Incorrect Result For Groupby With Limit

     [ https://issues.apache.org/jira/browse/HIVE-24579?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Krisztian Kasa reassigned HIVE-24579:
-------------------------------------

    Assignee: Krisztian Kasa

> Incorrect Result For Groupby With Limit
> ---------------------------------------
>
>                 Key: HIVE-24579
>                 URL: https://issues.apache.org/jira/browse/HIVE-24579
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 2.3.7, 3.1.2, 4.0.0
>            Reporter: Nemon Lou
>            Assignee: Krisztian Kasa
>            Priority: Major
>
> {code:sql}
> create table test(id int);
> explain extended select id,count(*) from test group by id limit 10;
> {code}
> There is an TopN unexpectly for map phase, which casues incorrect result.
> {code:sql}
> STAGE PLANS:
>   Stage: Stage-1
>     Tez
>       DagId: root_20210104141527_c599c0cd-ca2f-4c7d-a3cc-3a01d65c49a1:5
>       Edges:
>         Reducer 2 <- Map 1 (SIMPLE_EDGE)
>       DagName: root_20210104141527_c599c0cd-ca2f-4c7d-a3cc-3a01d65c49a1:5
>       Vertices:
>         Map 1 
>             Map Operator Tree:
>                 TableScan
>                   alias: test
>                   Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                   GatherStats: false
>                   Select Operator
>                     expressions: id (type: int)
>                     outputColumnNames: id
>                     Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                     Group By Operator
>                       aggregations: count()
>                       keys: id (type: int)
>                       mode: hash
>                       outputColumnNames: _col0, _col1
>                       Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                       Reduce Output Operator
>                         key expressions: _col0 (type: int)
>                         null sort order: a
>                         sort order: +
>                         Map-reduce partition columns: _col0 (type: int)
>                         Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                         tag: -1
>                         TopN: 10
>                         TopN Hash Memory Usage: 0.1
>                         value expressions: _col1 (type: bigint)
>                         auto parallelism: true
>             Execution mode: vectorized
>             Path -> Alias:
>               file:/user/hive/warehouse/test [test]
>             Path -> Partition:
>               file:/user/hive/warehouse/test 
>                 Partition
>                   base file name: test
>                   input format: org.apache.hadoop.mapred.TextInputFormat
>                   output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
>                   properties:
>                     COLUMN_STATS_ACCURATE {"BASIC_STATS":"true","COLUMN_STATS":{"id":"true"}}
>                     bucket_count -1
>                     bucketing_version 2
>                     column.name.delimiter ,
>                     columns id
>                     columns.comments 
>                     columns.types int
>                     file.inputformat org.apache.hadoop.mapred.TextInputFormat
>                     file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
>                     location file:/user/hive/warehouse/test
>                     name default.test
>                     numFiles 0
>                     numRows 0
>                     rawDataSize 0
>                     serialization.ddl struct test { i32 id}
>                     serialization.format 1
>                     serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                     totalSize 0
>                     transient_lastDdlTime 1609730190
>                   serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                 
>                     input format: org.apache.hadoop.mapred.TextInputFormat
>                     output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
>                     properties:
>                       COLUMN_STATS_ACCURATE {"BASIC_STATS":"true","COLUMN_STATS":{"id":"true"}}
>                       bucket_count -1
>                       bucketing_version 2
>                       column.name.delimiter ,
>                       columns id
>                       columns.comments 
>                       columns.types int
>                       file.inputformat org.apache.hadoop.mapred.TextInputFormat
>                       file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
>                       location file:/user/hive/warehouse/test
>                       name default.test
>                       numFiles 0
>                       numRows 0
>                       rawDataSize 0
>                       serialization.ddl struct test { i32 id}
>                       serialization.format 1
>                       serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                       totalSize 0
>                       transient_lastDdlTime 1609730190
>                     serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                     name: default.test
>                   name: default.test
>             Truncated Path -> Alias:
>               /test [test]
>         Reducer 2 
>             Execution mode: vectorized
>             Needs Tagging: false
>             Reduce Operator Tree:
>               Group By Operator
>                 aggregations: count(VALUE._col0)
>                 keys: KEY._col0 (type: int)
>                 mode: mergepartial
>                 outputColumnNames: _col0, _col1
>                 Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                 Limit
>                   Number of rows: 10
>                   Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                   File Output Operator
>                     compressed: false
>                     GlobalTableId: 0
>                     directory: file:/tmp/root/7160ea24-52b9-47c3-aafc-c9200263a1c6/hive_2021-01-04_14-15-27_601_190083924675700904-1/-mr-10001/.hive-staging_hive_2021-01-04_14-15-27_601_190083924675700904-1/-ext-10002
>                     NumFilesPerFileSink: 1
>                     Statistics: Num rows: 1 Data size: 13500 Basic stats: COMPLETE Column stats: NONE
>                     Stats Publishing Key Prefix: file:/tmp/root/7160ea24-52b9-47c3-aafc-c9200263a1c6/hive_2021-01-04_14-15-27_601_190083924675700904-1/-mr-10001/.hive-staging_hive_2021-01-04_14-15-27_601_190083924675700904-1/-ext-10002/
>                     table:
>                         input format: org.apache.hadoop.mapred.SequenceFileInputFormat
>                         output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat
>                         properties:
>                           columns _col0,_col1
>                           columns.types int:bigint
>                           escape.delim \
>                           hive.serialization.extend.additional.nesting.levels true
>                           serialization.escape.crlf true
>                           serialization.format 1
>                           serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                         serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>                     TotalFiles: 1
>                     GatherStats: false
>                     MultiFileSpray: false
>   Stage: Stage-0
>     Fetch Operator
>       limit: 10
>       Processor Tree:
>         ListSink
> Time taken: 0.102 seconds, Fetched: 143 row(s)
> {code}
>  



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