refactor(parquet): replace magic 8 literals with named constants#9751
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The literal `8` appeared in two distinct roles throughout `RleEncoder`, `RleDecoder`, and their tests. Replacing each with a named constant makes the intent explicit and prevents the two meanings from being confused. * `BIT_PACK_GROUP_SIZE = 8` The Parquet RLE/bit-packing hybrid format always bit-packs values in multiples of this count (spec: "we always bit-pack a multiple of 8 values at a time"). Every occurrence related to the staging buffer size, the repeat-count threshold that triggers the RLE decision, and the group-count arithmetic in bit-packed headers now uses this name. * `u8::BITS` (= 8, from std) Used wherever a bit-count is divided by 8 to obtain a byte-count (e.g. `ceil(bit_width, u8::BITS as usize)`). This is a bits-per-byte conversion, a fundamentally different concept from the packing-group size. No behaviour change. Signed-off-by: Hippolyte Barraud <hippolyte.barraud@datadoghq.com>
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Nice, looks like an improvement. |
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etseidl
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Apr 20, 2026
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Looks great to me. Thanks for distinguishing different uses of 8 😄
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Thanks @HippoBaro @jhorstmann and @etseidl I took the liberty of merging up from main to resolve a conflict 
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Thank you 🙇 |
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🚀 |
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Which issue does this PR close?
Rationale for this change
The literal
8appeared in two distinct roles throughoutRleEncoder,RleDecoder, and their tests.What changes are included in this PR?
Replacing each with a named constant makes the intent explicit and prevents the two meanings from being confused.
BIT_PACK_GROUP_SIZE = 8The Parquet RLE/bit-packing hybrid format always bit-packs values in multiples of this count (spec: "we always bit-pack a multiple of 8 values at a time"). Every occurrence related to the staging buffer size, the repeat-count threshold that triggers the RLE decision, and the group-count arithmetic in bit-packed headers now uses this name.u8::BITS(= 8, from std) Used wherever a bit-count is divided by 8 to obtain a byte-count (e.g.ceil(bit_width, u8::BITS as usize)). This is a bits-per-byte conversion, a fundamentally different concept from the packing-group size.No behaviour change.
Are these changes tested?
All tests passing.
Are there any user-facing changes?
None.