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https://issues.apache.org/jira/browse/IGNITE-22092?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Iurii Gerzhedovich updated IGNITE-22092:
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Priority: Major (was: Minor)
> Sql. Implement subquery decorrelation
> -------------------------------------
>
> Key: IGNITE-22092
> URL: https://issues.apache.org/jira/browse/IGNITE-22092
> Project: Ignite
> Issue Type: Improvement
> Components: sql
> Reporter: Maksim Zhuravkov
> Priority: Major
> Labels: ignite-3
>
> Rewriting correlated subqueries provides significant performance boost by
> removing redundant loops during execution and by allowing subsequent
> optimisations of flattened plans during planning.
> P.S.
> Apache calcite provides some means to decorrelate subqueries (via
> `RelDecorrelator`) but unfortunetly they are:
> - produce incorrect results (see
> https://issues.apache.org/jira/browse/IGNITE-16493 where decorrelating
> subquery produces incorrect result because a resulting plan contains a join
> with `equality` instead of is `not distinct from` predicate (thus breaking
> queries for tables that contain NULLs).
> - limited in scope.
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