During a performance review of a silver pipeline, a reviewer notices that the author registered a Python UDF to uppercase a country code and to split a full name, although both transformations are available as built-in Spark functions. The author asks why the reviewer insists on replacing the UDF with the native functions. Which explanation is correct?
Reveal answer
Correct answer: Built-in functions execute in the optimized engine with no Python serialization and remain visible to the optimizer.
Reference: https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-functions
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02 — The Myelin Layer · Canonical Discussion
Where the exam tries to trick you — and how those who passed solved it.
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No community synthesis consolidated for this question yet. Below is the verifiable official starting point — if you passed the exam, open the option dissection.
Official Answer (A): Built-in functions execute in the optimized engine with no Python serialization and remain visible to the optimizer.
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