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  1. Calcite
  2. CALCITE-4094

Allow SqlOperator of SqlKind#OTHER_FUNCTION to define a Strong.Policy

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 1.24.0
    • Component/s: core

      Description

      FilterJoinRule performs some optimizations based on RelOptUtil#simplifyJoin. Specifically, this part of the code:

      if (joinType.generatesNullsOnRight()
        && Strong.isNotTrue(filter, rightBitmap)) {
          joinType = joinType.cancelNullsOnRight();
      }
      

      allows e.g. a LEFT join with a condition on its RHS to be transformed into an INNER join, with the condition pushed on its right input.

      In order to achieve this, the utility class Strong defines a certain Policy map, depending on the SqlKind of a RexNode (i.e. depending on the filter condition). In case of operators such as EQUALS, NOT_EQUALS, LESS_THAN, etc, it defines Policy.ANY (i.e. expression is null if and only if at least one of its arguments is null). In case of a left join with conditions with this policy on the right-hand-side, the join gets simplified by this module because of the nullability of the right columns. However, in the case of SqlUserDefinedFunction the policy is the default Policy.AS_IS, which prevents the simplification from happening.

      It is proposed to enrich SqlUserDefinedFunction with an optional Strong.Policy, and adapt Strong code so that these functions can also benefit from this simplification.

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              • Assignee:
                rubenql Ruben Q L
                Reporter:
                rubenql Ruben Q L
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