Decode numeric to Decimal128 directly, without text round-trip#34
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@qsliu2017 thank you so much for the PR! It’s really great that you took a look at the project, benchmarked it, and The change looks good to me. Could you please add yourself to AUTHORS and fix the lint failures? After |
Replace the numeric_out text round-trip in slot_encoder's read_numeric_decimal128_with_scale with a direct decode of the PostgreSQL numeric varlena: accumulate the base-10000 NumericDigit array into an i128 at the target scale, ported from PG numeric.c internals. The decode lives in a new PostgreSQL-runtime-free pg_type::numeric module (pure, safe `numeric_to_decimal128(&[u8], scale, precision)` with its own NumericDecodeError); slot_encoder just detoasts, slices, calls it, and maps the error. Behavior is unchanged -- same NaN/Inf and out-of-range/precision handling -- and TPC-H Q1 results are identical while the conversion step gets much faster. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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@qsliu2017 thanks a lot for your contribution! |
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First of all, thanks for creating this awesome project!
Profiling pg_fusion on TPC-H Q1,
slot_encoder::datum::read_numeric_decimal128_with_scalewas the top hotspot. It converted each PG numeric by formatting it to a string and then parsing back into an i128.This PR replaces that with a direct decode of the numeric varlena, ported from Postgres' numeric.c.
With this PR, TPC-H Q1 speed up ~2.3x (from ~110s to ~48s, single-threaded) in my laptop.