xudong963 opened a new pull request, #21820: URL: https://github.com/apache/datafusion/pull/21820
## Which issue does this PR close? - Closes https://github.com/apache/datafusion/issues/21428. ## Rationale for this change This PR adds `BuildHasher`-based variants for `hash_utils` so callers can compute row hashes with a caller-provided hash builder instead of always using DataFusion's default `RandomState`. The main constraint is performance: `with_hashes` is a hot path, especially for string, dictionary, and nested array hashing. A previous version in #21429 caused measurable regressions in the default `RandomState` path, for example `large_utf8: single, no nulls` regressed from roughly `26.7us` to `36.3us`, and `large_utf8: multiple, no nulls` from roughly `112us` to `127us`. This version keeps the default path performance-oriented by avoiding a fully generic `BuildHasher` rewrite of the existing hot loops. ## What changes are included in this PR? This PR adds: - `with_hashes_with_hasher` - `create_hashes_with_hasher` - custom-hasher implementations for primitive, string, binary, byte-view, dictionary, and nested arrays - tests covering custom hashers, multi-column hashing, and dictionary equivalence The implementation intentionally uses a hybrid design: - Default `RandomState` leaf hot paths remain specialized. - Custom `BuildHasher` leaf paths live separately in `hash_utils/build_hasher.rs`. - Nested/structural logic is shared through an internal child-hashing adapter, so struct/list/map/union/run/dictionary behavior does not need to be broadly duplicated. The trade-off is that there is still some duplication for primitive/string/binary leaf loops. That duplication is intentional: those are the hottest loops, and keeping them separate prevents the existing `RandomState` path from becoming generic over `BuildHasher` or being perturbed by the custom-hasher implementation. ## Are these changes tested? Yes. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
