Rich-T-kid commented on code in PR #23187: URL: https://github.com/apache/datafusion/pull/23187#discussion_r3603997416
########## datafusion/physical-plan/src/aggregates/group_values/multi_group_by/dictionary.rs: ########## @@ -0,0 +1,373 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use crate::aggregates::group_values::multi_group_by::GroupColumn; +use arrow::array::{ + Array, ArrayRef, AsArray, BooleanBufferBuilder, DictionaryArray, PrimitiveArray, +}; +use arrow::datatypes::{ArrowDictionaryKeyType, ArrowNativeType, DataType, Field}; +use datafusion_common::{Result, exec_err}; +use std::marker::PhantomData; +use std::sync::Arc; + +/// A [`GroupColumn`] implementation for dictionary arrays. +/// wraps an inner [`GroupColumn`] that stores the dictionary values, and uses a null sentinel for null keys. +pub struct DictionaryGroupValuesColumn<K: ArrowDictionaryKeyType + Send + Sync> { + inner: Box<dyn GroupColumn>, + // unary array used as a null sentinel for dictionary keys that are null + null_array: ArrayRef, + _phantom: PhantomData<K>, +} + +impl<K: ArrowDictionaryKeyType + Send + Sync> DictionaryGroupValuesColumn<K> { + pub fn new(inner: Box<dyn GroupColumn>, field: &Field) -> Self { + let null_array = arrow::array::new_null_array(field.data_type(), 1); + Self { + inner, + null_array, + _phantom: PhantomData, + } + } + + fn into_dict(values: ArrayRef) -> ArrayRef { + let num_values = values.len(); + let keys: PrimitiveArray<K> = (0..num_values) + .map(|i| (!values.is_null(i)).then(|| K::Native::usize_as(i))) + .collect(); + Arc::new(DictionaryArray::<K>::new(keys, values)) + } + + /// Returns the index of the first null in `values`, or `None` if there are no nulls. + fn null_sentinel_index(values: &ArrayRef) -> Option<usize> { + values.nulls()?.iter().position(|valid| !valid) + } + + /// Returns an error if adding `additional` groups would overflow the key type's range. + // https://github.com/apache/datafusion/issues/23127 + fn check_key_overflow(current_len: usize, additional: usize) -> Result<()> { + if !Self::valid_bounds::<K>(current_len + additional) { Review Comment: Actually I think I understand what your refering to now. the check for key-overflow needs to be placed after we store new values in the internal `GroupColumns`. so instead of ```rust fn vectorized_append(&mut self, array: &ArrayRef, rows: &[usize]) -> Result<()> { let dict = array.as_dictionary::<K>(); .... write to inner groupColumn ``` we'd do ```rust ... write to inner groupColumn Self::check_key_overflow(self.inner.len(), 0)?; ``` now if the actually groups has exceed what we can store we'd error out here. -- 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]
