[
https://issues.apache.org/jira/browse/HIVE-4809?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Yin Huai updated HIVE-4809:
---------------------------
Assignee: Yin Huai
> ReduceSinkOperator of PTFOperator can have redundant key columns
> ----------------------------------------------------------------
>
> Key: HIVE-4809
> URL: https://issues.apache.org/jira/browse/HIVE-4809
> Project: Hive
> Issue Type: Improvement
> Reporter: Yin Huai
> Assignee: Yin Huai
>
> For example, we have a simple query like this ...
> {code:sql}
> SELECT x.a, x.b, count(x.b) OVER (PARTITION BY x.a) FROM src x;
> {\code}
> The plan of it is ...
> {code}
> 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:
> x
> TableScan
> alias: x
> Reduce Output Operator
> key expressions:
> expr: a
> type: int
> expr: a
> type: int
> sort order: ++
> Map-reduce partition columns:
> expr: a
> type: int
> tag: -1
> value expressions:
> expr: a
> type: int
> expr: b
> type: string
> Reduce Operator Tree:
> Extract
> PTF Operator
> Select Operator
> expressions:
> expr: _col0
> type: int
> expr: _col1
> type: string
> expr: _wcol0
> type: bigint
> outputColumnNames: _col0, _col1, _col2
> 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
> {\code}
> The ReduceSinkOperator has two "a" in its key columns. This redundancy can
> increase the size of map output.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
