zhuqi-lucas commented on PR #21820:
URL: https://github.com/apache/datafusion/pull/21820#issuecomment-4979096557

   Design looks reasonable — hybrid split makes the perf trade-off explicit and 
benchmarks confirm no regression on the default path.
   
   Three things:
   
   - **Test coverage**: only Int32 / Float64 / (Int32+Utf8 multi-col) exercise 
the custom-hasher path. Would be good to add at least Dictionary, Struct, and 
Utf8View with long strings (to hit the `HAS_BUFFERS=true` const-generic branch).
   
   - **Parity test**: since the leaf loops are intentionally duplicated for 
perf, a test that runs both paths with a shared hash builder (e.g. 
`RandomState` wrapped as `BuildHasher`) and asserts equal output would catch 
drift cheaply.
   
   - **Nit**: `hash_null_with_hasher` names its parameter `mul_col`; the 
original `hash_null` uses `multi_col`.
   
   **Question**: what's the near-term consumer of `create_hashes_with_hasher`? 
#21428 has the motivation but no concrete caller — helpful to know if there's a 
follow-up PR that consumes this.


-- 
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]

Reply via email to