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Posted to github@datafusion.apache.org by "liningpan (via GitHub)" <gi...@apache.org> on 2026/07/16 20:54:20 UTC

[I] Optimize redundant calls to UDFs producing `StructArray` [datafusion]

liningpan opened a new issue, #23655:
URL: https://github.com/apache/datafusion/issues/23655

   ### Is your feature request related to a problem or challenge?
   
   Since UDF can only return a single column as output, returning a `StructArray` is desired in many cases. However, accessing fields of the returned struct results in redundant calls to the UDF.
   
   ```sql
   SELECT
       example_struct(c)['a'],
       example_struct(c)['b']
   FROM (SELECT unnest(range(1,100)) as c)
   ```
   
   Datafusion produces the following projection step for the query, resulting in calling the UDF with the same column twice.
   
   ```
   ProjectionExec: expr=[get_field(example_struct(c@0), a) as example_struct(c)[a], get_field(example_struct(c@0), b) as example_struct(c)[b]]
   ```
   
   Note that calling the UDF in a CTE or view does not change the execution plan.
   
   Here is a minimal example [https://github.com/liningpan/udf-get-field-optimization].
   
   
   ### Describe the solution you'd like
   
   @adriangb mentioned that CSE (Common Sub-expression Elimination) optimizer might be able to handle this.
   
   ### Describe alternatives you've considered
   
   _No response_
   
   ### Additional context
   
   _No response_


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Re: [I] Optimize redundant calls to UDFs producing `StructArray` [datafusion]

Posted by "kosiew (via GitHub)" <gi...@apache.org>.
kosiew closed issue #23655: Optimize redundant calls to UDFs producing `StructArray`
URL: https://github.com/apache/datafusion/issues/23655


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Re: [I] Optimize redundant calls to UDFs producing `StructArray` [datafusion]

Posted by "tohuya6 (via GitHub)" <gi...@apache.org>.
tohuya6 commented on issue #23655:
URL: https://github.com/apache/datafusion/issues/23655#issuecomment-4998766963

   take


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