GH-533: Add ALP (Adaptive Lossless floating-Point) encoding specification#557
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prtkgaur wants to merge 1 commit intoapache:masterfrom
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GH-533: Add ALP (Adaptive Lossless floating-Point) encoding specification#557prtkgaur wants to merge 1 commit intoapache:masterfrom
prtkgaur wants to merge 1 commit intoapache:masterfrom
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Add the encoding specification for ALP (encoding value 10) to Encodings.md. ALP compresses FLOAT and DOUBLE columns by converting values to integers via decimal scaling, then applying Frame of Reference encoding and bit-packing. Values that cannot be losslessly round-tripped are stored as exceptions. The spec covers: - Page layout: 7-byte header, offset array, compressed vectors - Vector format: AlpInfo, ForInfo, packed values, exception data - Encoding math: two-step multiplication for cross-language consistency - Parameter selection, exception detection, and decoding steps Based on the paper "ALP: Adaptive Lossless floating-Point Compression" (Afroozeh and Boncz, SIGMOD 2024). Wire format matches the C++ Arrow and Java parquet-java implementations.
alamb
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This was referenced Mar 11, 2026
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Add the encoding specification for ALP (encoding value 10) to Encodings.md. ALP compresses FLOAT and DOUBLE columns by converting values to integers via decimal scaling, then applying Frame of Reference encoding and bit-packing. Values that cannot be losslessly round-tripped are stored as exceptions.
See rendered preview here: https://github.com/prtkgaur/parquet-format/blob/alpEncoding/Encodings.md#adaptive-lossless-floating-point-alp--10
The spec covers:
Based on the paper "ALP: Adaptive Lossless floating-Point Compression" (Afroozeh and Boncz, SIGMOD 2024). Wire format matches the C++ Arrow and Java parquet-java implementations.
Rationale for this change
What changes are included in this PR?
Do these changes have PoC implementations?