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https://issues.apache.org/jira/browse/HIVE-29121?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Seonggon Namgung updated HIVE-29121:
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Description:
This JIRA is an addendum patch to HIVE-24685 and aims to restore the compiler
logic from HIVE-17767.
During the substitution of HiveSubQRemoveRelBuilder with Calcite's RelBuilder
in HIVE-24685, Hive was changed to always use SemiJoin when handling
uncorrelated IN/EXISTS subqueries with logic == RelOptUtil.Logic.TRUE. Since
the SemiJoin is intended for use with correlated IN/EXISTS subqueries in
conjunction with AGGR removal (cf. HIVE-17767), we should avoid using SemiJoin
for the uncorrelated case, which neither benefits from AGGR removal nor allows
the application of rules that cannot handle HiveSemiJoin (e.g., join
reordering).
For clarity, the following combinations of query plans are attached. From the
attached plans, we can observe that HIVE-24685 introduces a SemiJoin without
removing HiveAggregate, unlike HIVE-17767.
The attached plans cover the following combinations:
* {Before HIVE-17767, After HIVE-17767, After HIVE-24685}
* {Correlated, Uncorrelated}
* {Before subquery removal, After subquery removal, After decorrelation}
We discovered this issue while investigating a performance regression in TPC-DS
Query 23.
was:
This JIRA is an addendum patch to HIVE-24685 and aims to restore the compiler
logic from HIVE-17767.
During the substitution of HiveSubQRemoveRelBuilder with Calcite's RelBuilder
in HIVE-24685, Hive was changed to always use SemiJoin when handling
uncorrelated IN/EXISTS subqueries with logic == RelOptUtil.Logic.TRUE. Since
the SemiJoin is intended for use with correlated IN/EXISTS subqueries in
conjunction with AGGR removal (cf. HIVE-17767), we should avoid using SemiJoin
for the uncorrelated case, which neither benefits from AGGR removal nor allows
the application of rules that cannot handle HiveSemiJoin (e.g., join
reordering).
For clarity, the following combinations of query plans are attached:
{Before HIVE-17767, After HIVE-17767, After HIVE-24685} * \{Correlated,
Uncorrelated} * \{Before subquery removal, After subquery removal, After
decorrelation}.
>From the attached plans, we can observe that HIVE-24685 introduces a SemiJoin
>without removing HiveAggregate, unlike HIVE-17767.
We discovered this issue while investigating a performance regression in TPC-DS
Query 23.
> Restore HiveSubQueryRemoveRule to use InnerJoin instead of SemiJoin for
> uncorrelated IN/EXISTS subqueries with RelOptUtil.Logic.TRUE.
> -------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-29121
> URL: https://issues.apache.org/jira/browse/HIVE-29121
> Project: Hive
> Issue Type: Improvement
> Environment: [^plan.example.txt]
> Reporter: Seonggon Namgung
> Assignee: Seonggon Namgung
> Priority: Major
> Attachments: plan.example.txt
>
>
> This JIRA is an addendum patch to HIVE-24685 and aims to restore the compiler
> logic from HIVE-17767.
> During the substitution of HiveSubQRemoveRelBuilder with Calcite's RelBuilder
> in HIVE-24685, Hive was changed to always use SemiJoin when handling
> uncorrelated IN/EXISTS subqueries with logic == RelOptUtil.Logic.TRUE. Since
> the SemiJoin is intended for use with correlated IN/EXISTS subqueries in
> conjunction with AGGR removal (cf. HIVE-17767), we should avoid using
> SemiJoin for the uncorrelated case, which neither benefits from AGGR removal
> nor allows the application of rules that cannot handle HiveSemiJoin (e.g.,
> join reordering).
> For clarity, the following combinations of query plans are attached. From the
> attached plans, we can observe that HIVE-24685 introduces a SemiJoin without
> removing HiveAggregate, unlike HIVE-17767.
> The attached plans cover the following combinations:
> * {Before HIVE-17767, After HIVE-17767, After HIVE-24685}
> * {Correlated, Uncorrelated}
> * {Before subquery removal, After subquery removal, After decorrelation}
> We discovered this issue while investigating a performance regression in
> TPC-DS Query 23.
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