[
https://issues.apache.org/jira/browse/IMPALA-11417?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
yx91490 updated IMPALA-11417:
-----------------------------
Attachment: (was: performance_compare.txt)
> support outer join elimination
> ------------------------------
>
> Key: IMPALA-11417
> URL: https://issues.apache.org/jira/browse/IMPALA-11417
> Project: IMPALA
> Issue Type: Improvement
> Reporter: Jian Zhang
> Assignee: Jian Zhang
> Priority: Major
> Attachments: performance_compare.txt
>
>
> We are facing a scenario where two tables are outer joined but only fields
> from the outer side table are used and the join key of the inner side table
> is guaranteed to be unique. Take the following simplified query as an
> example, where s.id is guaranteed to be unique:
> {code:sql}
> -- drop the test tables if exists:
> drop table if exists t;
> drop table if exists s;
> -- create test tables:
> create table t (s_id bigint, value bigint);
> create table s(id bigint, value bigint, primary key(id));
> -- the test SQL:
> select t.* from t left join s on t.s_id = s.id;
> {code}
> the above query can be optimized to the following if we can utilize the
> primary key information:
> {code:sql}
> select t.* from t;
> {code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
