perf: Optimize scalar fast path of to_hex function #20112
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sqllogictest
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might be related #20044 |
comphead
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Feb 2, 2026
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| #[inline] | ||
| fn to_hex_scalar<T: ToHex>(value: T) -> String { | ||
| let mut hex_buffer = [0u8; 16]; |
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we prob can make it reusable buffer?
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Thanks for the feedback. My initial thinking was the scalar fast path buffer is a fixed 16‑byte stack array, so it’s already very cheap and not heap-allocating. The array path is where buffer reuse matters and we already reuse a single buffer across the whole batch there. What do you think, should we still go ahead with the buffer reuse change?
comphead
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Thanks @kumarUjjawal I think this is great, however you can check if the reusable buffer can bring up more benefits
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Which issue does this PR close?
Rationale for this change
to_hex(used by benchmark itemshex_int/hex_long) previously routed evaluation throughmake_scalar_function(..., vec![]), which converts scalar inputs into size‑1 arrays before execution. This adds avoidable overhead for constant folding / scalar evaluation.What changes are included in this PR?
Int8/16/32/64andUInt8/16/32/64make_scalar_function(..., vec![])usageto_hex/scalar_i32to_hex/scalar_i64Are these changes tested?
Yes
Are there any user-facing changes?
No