Rich-T-kid commented on PR #23187: URL: https://github.com/apache/datafusion/pull/23187#issuecomment-5037228658
Okay finished with the PR updates. Ive added two test to assert that `DictionaryGroupValuesColumn` only stores at most `k` values where k is the number of unique values. [multi_col_groupby_dict_many_groups_two_values](https://github.com/apache/datafusion/pull/23187/changes#diff-f2de42a5c77f6d17ae04903cde3c31a1c2633397e1600b0de3331150b93e25f6R1435) & [append_only_stores_referenced_values](https://github.com/apache/datafusion/pull/23187/changes#diff-3a7e151acf3b161c9ffe712d8b834a397429508efd5710d0a2e6a1363397eabcR579) This provides with better performance for low cardinality but this becomes pure overhead for the 100% unique case (8k/8k & 65k/65k). if a key types stores too many unique values it will exist with an error instead of panicking at `build()`/`take_n()`. the latest PR also avoid re-allocations for hashes and other vectors so this should future bridge the gap for the high cardinality case. @kumarUjjawal could you take another look when you get a chance. -- 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]
