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https://issues.apache.org/jira/browse/CALCITE-6550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17880452#comment-17880452
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Julian Hyde edited comment on CALCITE-6550 at 9/9/24 11:21 PM:
---------------------------------------------------------------
[~njordan],Thanks for raising this. I see you changed the constructor of
{{SqlBasicFunction}} from {{private}} to {{protected}} in CALCITE-6358 and the
5 months since then it has been subclassed 12 times, including in CALCITE-6310,
CALCITE-6449, and CALCITE-6312.
{{SqlBasicFunction}} was not intended to be subclassed. This is tech debt that
*must* be fixed before 1.38.
was (Author: julianhyde):
[~njordan],Thanks for raising this. I see you changed the constructor of
{{SqlBasicFunction}} from {{private}} to {{protected}} in CALCITE-6358 and the
5 months since then it has been subclassed 12 times. This is tech debt that
must be fixed before 1.38.
> Improve SQL function overloading
> --------------------------------
>
> Key: CALCITE-6550
> URL: https://issues.apache.org/jira/browse/CALCITE-6550
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Norman Jordan
> Assignee: Norman Jordan
> Priority: Minor
> Labels: pull-request-available
> Fix For: 1.38.0
>
>
> All SQL functions across all SQL libraries as well as the standard functions
> are used as keys in a Map (in the class {*}RexImpTable{*}). The hashcode and
> equals methods currently only look at the name, kind and class.
> [https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/sql/SqlOperator.java#L424]
> [https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/sql/SqlOperator.java#L439]
> This causes a few problems:
> * Some functions may have the same name and kind but different sets of
> parameters
> * Two different SQL libraries may have functions with the same name and kind
> (and even parameters) but have different implementations.
> The current work around is to create new anonymous classes when needed to
> avoid collisions in the Map. Here is an example.
> https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java#L578
> The hashcode and equals methods should consider more information, such as the
> parameters as well as some way to differentiate similar functions in
> different libraries.
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