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https://issues.apache.org/jira/browse/HIVE-3972?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HIVE-3972:
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Attachment: HIVE-3972.D8349.4.patch
navis updated the revision "HIVE-3972 [jira] Support using multiple reducer for
fetching order by results".
Rebased to trunk
Reviewers: JIRA
REVISION DETAIL
https://reviews.facebook.net/D8349
CHANGE SINCE LAST DIFF
https://reviews.facebook.net/D8349?vs=27303&id=28557#toc
AFFECTED FILES
common/src/java/org/apache/hadoop/hive/conf/HiveConf.java
conf/hive-default.xml.template
ql/src/java/org/apache/hadoop/hive/ql/exec/FetchOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/FetchTask.java
ql/src/java/org/apache/hadoop/hive/ql/exec/MergeSortingFetcher.java
ql/src/java/org/apache/hadoop/hive/ql/exec/RowFetcher.java
ql/src/java/org/apache/hadoop/hive/ql/exec/SMBMapJoinOperator.java
ql/src/java/org/apache/hadoop/hive/ql/parse/QB.java
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java
ql/src/java/org/apache/hadoop/hive/ql/plan/FetchWork.java
ql/src/test/queries/clientpositive/orderby_query_bucketing.q
ql/src/test/results/clientpositive/orderby_query_bucketing.q.out
To: JIRA, navis
Cc: njain
> Support using multiple reducer for fetching order by results
> ------------------------------------------------------------
>
> Key: HIVE-3972
> URL: https://issues.apache.org/jira/browse/HIVE-3972
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Navis
> Assignee: Navis
> Priority: Minor
> Attachments: HIVE-3972.D8349.1.patch, HIVE-3972.D8349.2.patch,
> HIVE-3972.D8349.3.patch, HIVE-3972.D8349.4.patch
>
>
> Queries for fetching results which have lastly "order by" clause make final
> MR run with single reducer, which can be too much. For example,
> {code}
> select value, sum(key) as sum from src group by value order by sum;
> {code}
> If number of reducer is reasonable, multiple result files could be merged
> into single sorted stream in the fetcher level.
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