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docs: add an FAQ page with an answer on vectorized Java/Scala UDFs - #6778
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mbutrovich merged 2 commits intoOct 8, 2026
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The About section gets a Frequently Asked Questions page. Its first question is whether Comet plans an API for vectorized Java/Scala UDFs like the Rust UDF API. The answer gives what the prototype in apache#6697 found: for simple functions the vectorized form saved about 3 ns per row once the code generator's overheads were removed, which did not justify the API's cost to users. It also says where a vectorized function could still pay off, and points to apache#6694 for those use cases.
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Makes sense to me, thanks for documenting this @andygrove!
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Which issue does this PR close?
No issue. The answer records what the prototype in #6697 found for #6694.
Rationale for this change
With the Rust UDF API (#4459) documented, users may ask whether Java and Scala get an equivalent. #6697 prototyped one and found the gain too small to justify the cost to users, so this records the answer.
What changes are included in this PR?
about/faq.md, with one question so far: "Does Comet plan to add an API for vectorized Java/Scala UDFs similar to the Rust UDF API?"The answer's figure comes from
CometJvmUdfBenchmarkin #6697, measured with #6715.How are these changes tested?
Documentation only.
prettier --checkpasses. The docs site builds only on pushes to main, so the page has not been rendered.