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https://issues.apache.org/jira/browse/HIVE-16600?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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liyunzhang_intel updated HIVE-16600:
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Attachment: HIVE-16600.11.patch
[~lirui]: changes in HIVE-16600.11.patch
1. check all branches to verify whether there is LIMIT after RS, once condition
matches, return true( this is an order by limit case), If TermialOperator is
encountered, do not search its children any more.
2. add a new unit test like "select * from A order by columnB limit N"
3. remove case like following as after HIVE-6348, the physical plan of
following query will be:
query:
{code}
FROM (select key,value from src order by key) a
INSERT OVERWRITE TABLE e1
SELECT key
INSERT OVERWRITE TABLE e2
SELECT key limit xx;
{code}
physical plan:
{code}
TS[0]-SEL[1]-FS[3]
-LIM[5]-RS[6]-SEL[7]-LIM[8]-FS[9]
{code}
we judge above case in the same way we do in "select * from A order by columnB
limit N)"
> 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-16600.10.patch, HIVE-16600.11.patch,
> HIVE-16600.1.patch, HIVE-16600.2.patch, HIVE-16600.3.patch,
> HIVE-16600.4.patch, HIVE-16600.5.patch, HIVE-16600.6.patch,
> HIVE-16600.7.patch, HIVE-16600.8.patch, HIVE-16600.9.patch, mr.explain,
> mr.explain.log.HIVE-16600, Node.java,
> TestSetSparkReduceParallelism_MultiInsertCase.java
>
>
> 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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