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Posted to issues@quickstep.apache.org by "Zuyu Zhang (JIRA)" <ji...@apache.org> on 2018/04/23 20:09:00 UTC
[jira] [Updated] (QUICKSTEP-118) Optimization Rule For Union of
same subqueries
[ https://issues.apache.org/jira/browse/QUICKSTEP-118?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zuyu Zhang updated QUICKSTEP-118:
---------------------------------
Description:
Currently, [the following query|https://github.com/apache/incubator-quickstep/blob/master/query_optimizer/tests/physical_generator/Select.test#L3156] is convert into a `UnionAll` followed by `Aggregate` for de-duplication.
{code:java}
SELECT int_col FROM test
UNION
SELECT int_col FROM test;
{code}
The optimizer should, however, transform such query into a simple aggregate query:
{code:java}
SELECT int_col FROM test GROUP BY int_col;
{code}
was:
Currently, [the following query|https://github.com/apache/incubator-quickstep/blob/master/query_optimizer/tests/physical_generator/Select.test#L3156] is convert into a `UnionAll` followed by `Aggregate` for de-duplication.
{code:java}
SELECT int_col FROM test
UNION
SELECT int_col FROM test;
{code}
The optimizer should, however, transform such query into a simple select query:
{code:java}
SELECT int_col FROM test GROUP BY int_col;
{code}
> Optimization Rule For Union of same subqueries
> ----------------------------------------------
>
> Key: QUICKSTEP-118
> URL: https://issues.apache.org/jira/browse/QUICKSTEP-118
> Project: Apache Quickstep
> Issue Type: Improvement
> Components: Query Optimizer
> Reporter: Zuyu Zhang
> Priority: Minor
>
> Currently, [the following query|https://github.com/apache/incubator-quickstep/blob/master/query_optimizer/tests/physical_generator/Select.test#L3156] is convert into a `UnionAll` followed by `Aggregate` for de-duplication.
> {code:java}
> SELECT int_col FROM test
> UNION
> SELECT int_col FROM test;
> {code}
>
> The optimizer should, however, transform such query into a simple aggregate query:
> {code:java}
> SELECT int_col FROM test GROUP BY int_col;
> {code}
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