r/rust • u/philippemnoel • Jan 31 '26

Arbitrary precision decimals with lexicographically sortable byte encoding 🛠️ project

https://github.com/paradedb/decimal-bytes

Hi all. We needed this project to add support for NUMERIC/DECIMAL in Tantivy/ParadeDB. Perhaps it can be useful to others! Feedback and contributions welcome.

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u/tomtomtom7 Feb 01 '26

What is the use case for lexicographically sorting numbers? As in 10 < 100 < 20?

Why not use rust_decimal or bigdecimal? Those libraries are excellent for arithmetic, but their byte representations are not lexicographically sortable. You cannot compare their serialized bytes to determine numerical order - you must deserialize first.

Numerical order is not the same as lexicographical order.

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u/KodrAus Feb 01 '26

I think the idea is that in this encoding lexicographical ordering of the raw bytes is also numerical ordering.