comphead commented on code in PR #3893: URL: https://github.com/apache/datafusion-comet/pull/3893#discussion_r3034197373
########## native/shuffle/src/partitioners/empty_schema.rs: ########## @@ -0,0 +1,135 @@ +// 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::metrics::ShufflePartitionerMetrics; +use crate::partitioners::ShufflePartitioner; +use crate::ShuffleBlockWriter; +use arrow::array::RecordBatch; +use arrow::datatypes::SchemaRef; +use datafusion::common::DataFusionError; +use std::fs::OpenOptions; +use std::io::{BufWriter, Seek, Write}; +use tokio::time::Instant; + +/// A partitioner for zero-column schemas (e.g. queries where ColumnPruning removes all columns). +/// This handles shuffles for operations like COUNT(*) that produce empty-schema record batches +/// but contain a valid row count. Accumulates the total row count and writes a single +/// zero-column IPC batch to partition 0. All other partitions get empty entries in the index file. +pub(crate) struct EmptySchemaShufflePartitioner { Review Comment: would be useful to attach a data flow graph or something, so can figure how data transforms across shuffle phases? -- 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]
