[jira] [Created] (CALCITE-4467) Incorrect simplification for 'NaN' value

["Jesus Camacho Rodriguez (Jira)" <ji...@apache.org>]

Jesus Camacho Rodriguez created CALCITE-4467:
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             Summary: Incorrect simplification for 'NaN' value
                 Key: CALCITE-4467
                 URL: https://issues.apache.org/jira/browse/CALCITE-4467
             Project: Calcite
          Issue Type: Bug
          Components: core
            Reporter: Jesus Camacho Rodriguez
            Assignee: Jesus Camacho Rodriguez


{{RexSimplify}} simplifies {{x = x}} to {{null or x is not null}} (similarly <= and >=), and {{x != x}} to {{null and x is null}} (similarly < and >).
https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L363

This may not be applicable in some cases. For instance, if the type of x is floating-point, x could be 'NaN'. While some RDBMS consider 'NaN' = 'NaN' (e.g., Postgres), some others consider 'NaN' != 'NaN' following the IEEE 754 standard. For the latest, the rewriting above will result in incorrect results.

I think we should simply ignore this simplification for floating-point type.



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