[CALCITE-7711] Add a rule to convert LEFT or RIGHT OUTER JOIN with IS NULL to ANTI JOIN - #5175
[CALCITE-7711] Add a rule to convert LEFT or RIGHT OUTER JOIN with IS NULL to ANTI JOIN#5175zzwqqq wants to merge 2 commits into
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… NULL to ANTI JOIN
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| * <p>is equivalent to | ||
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| * <pre>{@code |
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I think having a plan before and after is more useful than having this equivalent SQL.
You can keep the SQL for the original query, though.
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Thanks for reviewing. I've added a plan example.
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| /** Returns an {@code IS NULL} condition that identifies a null-generated | ||
| * outer-join row, or null if there is no such condition. */ |
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The condition must be over an input field which is not nullable in the input.
That is implied by the JavaDoc, but is subtle, it deserves to be in the JavaDoc.
You can say rightField IS NULL where rightField is a non-nullable column from the right input (for a left join).
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Thanks. I've updated the Javadoc to describe the requirement.
xiedeyantu
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xiedeyantu
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Since Mihai has already reviewed it, I only raised a few minor issues.
| import org.junit.jupiter.api.Test; | ||
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| /** Tests for {@link OuterJoinToAntiJoinRule}. */ | ||
| class OuterJoinToAntiJoinRuleTest { |
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We can add JIRA title in the java doc.
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Thanks. I've added the title.
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| !set planner-rules original | ||
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| # OuterJoinToAntiJoinRule converts the null-generating side's IS NULL filter. |
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JIRA title also should be added here.
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Thanks. I've added the title here too.
| join.getCluster().getRexBuilder()); | ||
| final RelTraitSet traitSet = join.getTraitSet(); | ||
| final Join antiJoin = | ||
| join.copy(traitSet, condition, newLeft, newRight, |
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Would it be better to switch to RelBuilder.join?
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Thanks. Changed the rule to use RelBuilder.join and retain the original join hints. Correlated RIGHT joins are left unchanged because swapping the inputs would require remapping correlation references.
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@xiedeyantu please approve if you are happy |
mihaibudiu
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LGTM-will-merge-soon
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next step: squashing |
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Jira Link
CALCITE-7711
Changes Proposed
Add an optional rule for LEFT and RIGHT joins. The rule should match a top-level IS NULL conjunct on the null-generating input. The conversion is safe when the underlying input field is non-nullable, or when the join condition cannot be TRUE while that field is nullable. Other filter conjuncts and the original row type should be preserved.
Representing the operation as an ANTI join allows subsequent rules to produce physical anti joins and the planner to cost those alternatives.