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https://issues.apache.org/jira/browse/HIVE-16600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16004325#comment-16004325
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Rui Li commented on HIVE-16600:
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Hi [~kellyzly], please check your patch, seems it doesn't build.
Meanwhile, you have to update {{testconfiguration.properties}} for the test
framework to pick up the new test. Since the test is only intended for spark,
you can add it in the {{spark.only.query.files}} section.
Some comments about the new qtest:
# Why do we need {{cast(key as double) as keyD}}? It's not needed in the target
table right?
# The data in the target tables is not ordered. You should add {{--
SORT_QUERY_RESULTS}} to the test.
# It's quite interesting that we have an extra reduce stage when there's limit
in multi insert. The extra stage only does the limit. And this isn't necessary
because we're sorting with only one reducer. Per my experience, this won't
happen with single insert. So please do some investigation on this. I think the
extra stage can be removed, otherwise, there's no point in disabling parallel
order by in this case.
> Refactor SetSparkReducerParallelism#needSetParallelism to enable parallel
> order by in multi_insert cases
> --------------------------------------------------------------------------------------------------------
>
> Key: HIVE-16600
> URL: https://issues.apache.org/jira/browse/HIVE-16600
> Project: Hive
> Issue Type: Sub-task
> Reporter: liyunzhang_intel
> Assignee: liyunzhang_intel
> Attachments: HIVE-16600.1.patch, HIVE-16600.2.patch
>
>
> multi_insert_gby.case.q
> {code}
> set hive.exec.reducers.bytes.per.reducer=256;
> set hive.optimize.sampling.orderby=true;
> drop table if exists e1;
> drop table if exists e2;
> create table e1 (key string, value string);
> create table e2 (key string);
> FROM (select key, cast(key as double) as keyD, value from src order by key) a
> INSERT OVERWRITE TABLE e1
> SELECT key, value
> INSERT OVERWRITE TABLE e2
> SELECT key;
> select * from e1;
> select * from e2;
> {code}
> the parallelism of Sort is 1 even we enable parallel order
> by("hive.optimize.sampling.orderby" is set as "true"). This is not
> reasonable because the parallelism should be calcuated by
> [Utilities.estimateReducers|https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/optimizer/spark/SetSparkReducerParallelism.java#L170]
> this is because SetSparkReducerParallelism#needSetParallelism returns false
> when [children size of
> RS|https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/optimizer/spark/SetSparkReducerParallelism.java#L207]
> is greater than 1.
> in this case, the children size of {{RS[2]}} is two.
> the logical plan of the case
> {code}
> TS[0]-SEL[1]-RS[2]-SEL[3]-SEL[4]-FS[5]
> -SEL[6]-FS[7]
> {code}
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