R-JunmingChen commented on code in PR #37100: URL: https://github.com/apache/arrow/pull/37100#discussion_r1364757116
########## cpp/src/arrow/compute/kernels/aggregate_basic_internal.h: ########## @@ -912,6 +912,122 @@ struct NullMinMaxImpl : public ScalarAggregator { } }; +template <SimdLevel::type SimdLevel> +struct DictionaryMinMaxImpl : public ScalarAggregator { + using ThisType = DictionaryMinMaxImpl<SimdLevel>; + + DictionaryMinMaxImpl(std::shared_ptr<DataType> out_type, ScalarAggregateOptions options) + : options(std::move(options)), + out_type(std::move(out_type)), + has_nulls(false), + count(0), + min(nullptr), + max(nullptr) { + this->options.min_count = std::max<uint32_t>(1, this->options.min_count); + } + + Status Consume(KernelContext* ctx, const ExecSpan& batch) override { + if (batch[0].is_scalar()) { + return Status::NotImplemented("No min/max implemented for DictionaryScalar"); + } + + DictionaryArray dict_arr(batch[0].array.ToArrayData()); + ARROW_ASSIGN_OR_RAISE(auto compacted_arr, dict_arr.Compact(ctx->memory_pool())); + const DictionaryArray& compacted_dict_arr = + checked_cast<const DictionaryArray&>(*compacted_arr); + if (compacted_dict_arr.length() - compacted_dict_arr.null_count() == 0) { + return Status::OK(); + } + this->has_nulls |= compacted_dict_arr.null_count() > 0; + this->count += compacted_dict_arr.length() - compacted_dict_arr.null_count(); + + std::shared_ptr<Scalar> dict_min; + std::shared_ptr<Scalar> dict_max; + if (compacted_dict_arr.length() - compacted_dict_arr.null_count() == 1) { + ARROW_ASSIGN_OR_RAISE(dict_min, compacted_dict_arr.dictionary()->GetScalar(0)); Review Comment: Since the `compacted_dict_arr.null_count()` only counts the indices and the dictionary is compacted, the method should be correct. I agree it's premature optimization, let's remove it. -- 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: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org