Aleksey Plekhanov created IGNITE-14635:
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Summary: 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
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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