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https://issues.apache.org/jira/browse/IMPALA-11417?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Becker updated IMPALA-11417:
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Target Version: Impala 4.3.0 (was: Impala 4.2.0)
> 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
>
> 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}
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