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https://issues.apache.org/jira/browse/HIVE-4927?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HIVE-4927:
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Attachment: HIVE-4927.D11811.1.patch
yhuai requested code review of "HIVE-4927 [jira] When we merge two MapJoin
MapRedTasks, the TableScanOperator of the second one should be removed".
Reviewers: JIRA
remove the unnecessary TableScanOperator
set hive.auto.convert.join=true;
set hive.auto.convert.join.noconditionaltask=true;
EXPLAIN
SELECT x1.key AS key FROM src x1 JOIN src1 y1 ON (x1.key = y1.key) JOIN src1 y2
ON (x1.value = y2.value) GROUP BY x1.key;
We will get a NPE from MetadataOnlyOptimizer. The reason is that the operator
tree of the MapRedTask evaluating two MapJoins is
TS1->MapJoin1->TS2->MapJoin2->...
We should remove the TS2...
TEST PLAN
EMPTY
REVISION DETAIL
https://reviews.facebook.net/D11811
AFFECTED FILES
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/CommonJoinTaskDispatcher.java
ql/src/test/results/clientpositive/multiMapJoin1.q.out
MANAGE HERALD RULES
https://reviews.facebook.net/herald/view/differential/
WHY DID I GET THIS EMAIL?
https://reviews.facebook.net/herald/transcript/28053/
To: JIRA, yhuai
> When we merge two MapJoin MapRedTasks, the TableScanOperator of the second
> one should be removed
> ------------------------------------------------------------------------------------------------
>
> Key: HIVE-4927
> URL: https://issues.apache.org/jira/browse/HIVE-4927
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Affects Versions: 0.12.0
> Reporter: Yin Huai
> Assignee: Yin Huai
> Attachments: HIVE-4927.D11811.1.patch
>
>
> {code}
> set hive.auto.convert.join=true;
> set hive.auto.convert.join.noconditionaltask=true;
> EXPLAIN
> SELECT x1.key AS key FROM src x1 JOIN src1 y1 ON (x1.key = y1.key) JOIN src1
> y2 ON (x1.value = y2.value) GROUP BY x1.key;
> {\code}
> We will get a NPE from MetadataOnlyOptimizer. The reason is that the operator
> tree of the MapRedTask evaluating two MapJoins is
> {code}
> TS1->MapJoin1->TS2->MapJoin2->...
> {\code}
> We should remove the TS2...
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