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https://issues.apache.org/jira/browse/DRILL-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15852335#comment-15852335
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ASF GitHub Bot commented on DRILL-4963:
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Github user paul-rogers commented on the issue:
https://github.com/apache/drill/pull/701
Thank you for the very clear explanation. It is now obvious that the
original lazy init design relied on the "found/not found" semantics of a simple
name match: no ambiguity there. However, there is ambiguity with the overload
rules. Clearly, at planning stage, we need to check that our entire list of
candidate functions is consistent with ZK. Your design for that seems quite
good.
I wonder, at execution time, do we save a fully qualified function name so
we can go back to the "found/not found" trick? That is, do we save the function
as "foo( INT, VARCHAR )" or do we repeat the type inference at runtime?
I will do a detailed review of the code next.
> Issues when overloading Drill native functions with dynamic UDFs
> ----------------------------------------------------------------
>
> Key: DRILL-4963
> URL: https://issues.apache.org/jira/browse/DRILL-4963
> Project: Apache Drill
> Issue Type: Bug
> Components: Functions - Drill
> Affects Versions: 1.9.0
> Reporter: Roman
> Assignee: Arina Ielchiieva
> Fix For: Future
>
> Attachments: subquery_udf-1.0.jar, subquery_udf-1.0-sources.jar,
> test_overloading-1.0.jar, test_overloading-1.0-sources.jar
>
>
> I created jar file which overloads 3 DRILL native functions
> (LOG(VARCHAR-REQUIRED), CURRENT_DATE(VARCHAR-REQUIRED) and
> ABS(VARCHAR-REQUIRED,VARCHAR-REQUIRED)) and registered it as dynamic UDF.
> If I try to use my functions I will get errors:
> {code:xml}
> SELECT CURRENT_DATE('test') FROM (VALUES(1));
> {code}
> Error: FUNCTION ERROR: CURRENT_DATE does not support operand types (CHAR)
> SQL Query null
> {code:xml}
> SELECT ABS('test','test') FROM (VALUES(1));
> {code}
> Error: FUNCTION ERROR: ABS does not support operand types (CHAR,CHAR)
> SQL Query null
> {code:xml}
> SELECT LOG('test') FROM (VALUES(1));
> {code}
> Error: SYSTEM ERROR: DrillRuntimeException: Failure while materializing
> expression in constant expression evaluator LOG('test'). Errors:
> Error in expression at index -1. Error: Missing function implementation:
> castTINYINT(VARCHAR-REQUIRED). Full expression: UNKNOWN EXPRESSION.
> But if I rerun all this queries after "DrillRuntimeException", they will run
> correctly. It seems that Drill have not updated the function signature before
> that error. Also if I add jar as usual UDF (copy jar to
> /drill_home/jars/3rdparty and restart drillbits), all queries will run
> correctly without errors.
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