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https://issues.apache.org/jira/browse/HIVE-4002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HIVE-4002:
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Attachment: HIVE-4002.D8739.4.patch
navis updated the revision "HIVE-4002 [jira] Fetch task aggregation for simple
group by query".
Addressed comments
Reviewers: JIRA
REVISION DETAIL
https://reviews.facebook.net/D8739
CHANGE SINCE LAST DIFF
https://reviews.facebook.net/D8739?vs=38829&id=39063#toc
AFFECTED FILES
common/src/java/org/apache/hadoop/hive/conf/HiveConf.java
ql/src/java/org/apache/hadoop/hive/ql/exec/DemuxOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/FetchOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/GroupByOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/JoinOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/MuxOperator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/Operator.java
ql/src/java/org/apache/hadoop/hive/ql/exec/PartitionKeySampler.java
ql/src/java/org/apache/hadoop/hive/ql/exec/UDTFOperator.java
ql/src/java/org/apache/hadoop/hive/ql/optimizer/Optimizer.java
ql/src/java/org/apache/hadoop/hive/ql/optimizer/SimpleFetchAggregation.java
ql/src/java/org/apache/hadoop/hive/ql/optimizer/SimpleFetchOptimizer.java
ql/src/java/org/apache/hadoop/hive/ql/parse/MapReduceCompiler.java
ql/src/java/org/apache/hadoop/hive/ql/parse/ParseContext.java
ql/src/java/org/apache/hadoop/hive/ql/parse/RowResolver.java
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java
ql/src/test/queries/clientpositive/fetch_aggregation.q
ql/src/test/results/clientpositive/fetch_aggregation.q.out
ql/src/test/results/compiler/plan/groupby1.q.xml
ql/src/test/results/compiler/plan/groupby2.q.xml
ql/src/test/results/compiler/plan/groupby3.q.xml
ql/src/test/results/compiler/plan/groupby5.q.xml
serde/src/java/org/apache/hadoop/hive/serde2/SerDeUtils.java
To: JIRA, navis
Cc: yhuai
> Fetch task aggregation for simple group by query
> ------------------------------------------------
>
> Key: HIVE-4002
> URL: https://issues.apache.org/jira/browse/HIVE-4002
> Project: Hive
> Issue Type: Improvement
> Components: Query Processor
> Reporter: Navis
> Assignee: Navis
> Priority: Minor
> Attachments: HIVE-4002.D8739.1.patch, HIVE-4002.D8739.2.patch,
> HIVE-4002.D8739.3.patch, HIVE-4002.D8739.4.patch
>
>
> Aggregation queries with no group-by clause (for example, select count(*)
> from src) executes final aggregation in single reduce task. But it's too
> small even for single reducer because the most of UDAF generates just single
> row for map aggregation. If final fetch task can aggregate outputs from map
> tasks, shuffling time can be removed.
> This optimization transforms operator tree something like,
> TS-FIL-SEL-GBY1-RS-GBY2-SEL-FS + FETCH-TASK
> into
> TS-FIL-SEL-GBY1-FS + FETCH-TASK(GBY2-SEL-LS)
> With the patch, time taken for auto_join_filters.q test reduced to 6 min (10
> min, before).
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