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Posted to issues@ignite.apache.org by "Yury Gerzhedovich (Jira)" <ji...@apache.org> on 2021/06/18 09:34:02 UTC

[jira] [Updated] (IGNITE-14635) Calcite engine. EXCEPT operator using anti-join

     [ https://issues.apache.org/jira/browse/IGNITE-14635?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Yury Gerzhedovich updated IGNITE-14635:
---------------------------------------
    Labels: calcite2-required calcite3-required  (was: )

> Calcite engine. EXCEPT operator using anti-join
> -----------------------------------------------
>
>                 Key: IGNITE-14635
>                 URL: https://issues.apache.org/jira/browse/IGNITE-14635
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Aleksey Plekhanov
>            Priority: Minor
>              Labels: calcite2-required, calcite3-required
>
> Currently, EXCEPT operator implemented as hash aggregation of underlying inputs, but in some cases ([all=false], inputs are colocated and have required collations) perhaps anti-join will be more effective (but benchmarking is needed) and produce streamed output.
> For example, query like {{SELECT f1 FROM t1 EXCEPT SELECT f1 FROM t2}} could be rewritten to {{SELECT DISTINCT f1 FROM t1 ANTI JOIN t2 USING (f1)}}.



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