[
https://issues.apache.org/jira/browse/CALCITE-7264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18035116#comment-18035116
]
Stamatis Zampetakis commented on CALCITE-7264:
----------------------------------------------
I was convinced that the existing {{SqlOperator#isSafeOperator}} introduced by
CALCITE-7032 was sufficient for making the behavior in simplifier configurable.
Why do need additional APIs?
> New API for determining if an operator may throw
> ------------------------------------------------
>
> Key: CALCITE-7264
> URL: https://issues.apache.org/jira/browse/CALCITE-7264
> Project: Calcite
> Issue Type: New Feature
> Reporter: Thomas Rebele
> Priority: Major
>
> The SQL standard defines that 1/0 throws an exception. Calcite follows the
> standard here. However, some projects that use Calcite (e.g., Hive) define
> the result of 1/0 as NULL. This may lead to different results in RexSimplify:
> E.g., IS NULL(1/0) would throw for the SQL standard semantics, but would
> return TRUE for the Hive semantics.
> RexSimplify handles this with a concept called "safe" defined in
> [RexSimplify#isSafeExpression|https://github.com/apache/calcite/blob/34989b0ed7793cedf713c2f159de6247a730458c/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L1631].
> The safe operators are defined in
> [RexSimplify.SafeRexVisitor|https://github.com/apache/calcite/blob/34989b0ed7793cedf713c2f159de6247a730458c/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L1490].
> The goal of this ticket is to make the behavior configurable. We can
> continue to attach the safeness to the operators, so we could move the
> safeOps set somewhere else. Here some examples:
> * boolean RelDataTypeSystem#canOperatorThrow(SqlKind op)
> * boolean RelDataTypeSystem#canOperatorThrow(SqlOperator op)
> * boolean RelDataTypeSystem#isNoExceptOperator(...) //noexcept notion
> borrowed from C++
> * boolean RelDataTypeSystem#isSafeOperator
> * Set<SqlKind> RelDataTypeSystem#noexceptOperators()
> The safeness information would be useful for other parts of the code as well,
> e.g., CALCITE-5315.
> See the related discussions:
> *
> https://issues.apache.org/jira/browse/CALCITE-7145?focusedCommentId=18016030#comment-18016030
> * [http://lists.apache.org/thread/cp7h28k1yfxv421q12y1wopbwgrzdzrx]
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
