jonathanc-n commented on code in PR #17482: URL: https://github.com/apache/datafusion/pull/17482#discussion_r2350515225
########## datafusion/physical-plan/src/joins/piecewise_merge_join/classic_join.rs: ########## @@ -0,0 +1,1471 @@ +// 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. + +//! Stream Implementation for PiecewiseMergeJoin's Classic Join (Left, Right, Full, Inner) + +use arrow::array::{ + new_null_array, Array, PrimitiveArray, PrimitiveBuilder, RecordBatchOptions, +}; +use arrow::compute::take; +use arrow::datatypes::{UInt32Type, UInt64Type}; +use arrow::{ + array::{ + ArrayRef, RecordBatch, UInt32Array, UInt32Builder, UInt64Array, UInt64Builder, + }, + compute::{sort_to_indices, take_record_batch}, +}; +use arrow_schema::{ArrowError, Schema, SchemaRef, SortOptions}; +use datafusion_common::NullEquality; +use datafusion_common::{exec_err, internal_err, Result}; +use datafusion_execution::{RecordBatchStream, SendableRecordBatchStream}; +use datafusion_expr::{JoinType, Operator}; +use datafusion_physical_expr::PhysicalExprRef; +use futures::{Stream, StreamExt}; +use std::{cmp::Ordering, task::ready}; +use std::{sync::Arc, task::Poll}; + +use crate::handle_state; +use crate::joins::piecewise_merge_join::exec::{BufferedSide, BufferedSideReadyState}; +use crate::joins::piecewise_merge_join::utils::need_produce_result_in_final; +use crate::joins::utils::{compare_join_arrays, get_final_indices_from_shared_bitmap}; +use crate::joins::utils::{BuildProbeJoinMetrics, StatefulStreamResult}; +pub(super) enum PiecewiseMergeJoinStreamState { + WaitBufferedSide, + FetchStreamBatch, + ProcessStreamBatch(StreamedBatch), + ExhaustedStreamSide, + Completed, +} + +impl PiecewiseMergeJoinStreamState { + // Grab mutable reference to the current stream batch + fn try_as_process_stream_batch_mut(&mut self) -> Result<&mut StreamedBatch> { + match self { + PiecewiseMergeJoinStreamState::ProcessStreamBatch(state) => Ok(state), + _ => internal_err!("Expected streamed batch in StreamBatch"), + } + } +} + +pub(super) struct StreamedBatch { + pub batch: RecordBatch, + values: Vec<ArrayRef>, +} + +impl StreamedBatch { + #[allow(dead_code)] + fn new(batch: RecordBatch, values: Vec<ArrayRef>) -> Self { + Self { batch, values } + } + + fn values(&self) -> &Vec<ArrayRef> { + &self.values + } +} + +pub(super) struct ClassicPWMJStream { + // Output schema of the `PiecewiseMergeJoin` + pub schema: Arc<Schema>, + + // Physical expression that is evaluated on the streamed side + // We do not need on_buffered as this is already evaluated when + // creating the buffered side which happens before initializing + // `PiecewiseMergeJoinStream` + pub on_streamed: PhysicalExprRef, + // Type of join + pub join_type: JoinType, + // Comparison operator + pub operator: Operator, + // Streamed batch + pub streamed: SendableRecordBatchStream, + // Streamed schema + streamed_schema: SchemaRef, + // Buffered side data + buffered_side: BufferedSide, + // Tracks the state of the `PiecewiseMergeJoin` + state: PiecewiseMergeJoinStreamState, + // Sort option for buffered and streamed side (specifies whether + // the sort is ascending or descending) + sort_option: SortOptions, + // Metrics for build + probe joins + join_metrics: BuildProbeJoinMetrics, + // Tracking incremental state for emitting record batches + batch_process_state: BatchProcessState, + // Creates batch size + batch_size: usize, +} + +impl RecordBatchStream for ClassicPWMJStream { + fn schema(&self) -> SchemaRef { + Arc::clone(&self.schema) + } +} + +// `PiecewiseMergeJoinStreamState` is separated into `WaitBufferedSide`, `FetchStreamBatch`, +// `ProcessStreamBatch`, `ExhaustedStreamSide` and `Completed`. +// +// Classic Joins +// 1. `WaitBufferedSide` - Load in the buffered side data into memory. +// 2. `FetchStreamBatch` - Fetch + sort incoming stream batches. We switch the state to +// `ExhaustedStreamBatch` once stream batches are exhausted. +// 3. `ProcessStreamBatch` - Compare stream batch row values against the buffered side data. +// 4. `ExhaustedStreamBatch` - If the join type is Left or Inner we will return state as +// `Completed` however for Full and Right we will need to process the matched/unmatched rows. +impl ClassicPWMJStream { + // Creates a new `PiecewiseMergeJoinStream` instance + #[allow(clippy::too_many_arguments)] + pub fn try_new( + schema: Arc<Schema>, + on_streamed: PhysicalExprRef, + join_type: JoinType, + operator: Operator, + streamed: SendableRecordBatchStream, + buffered_side: BufferedSide, + state: PiecewiseMergeJoinStreamState, + sort_option: SortOptions, + join_metrics: BuildProbeJoinMetrics, + batch_size: usize, + ) -> Self { + let streamed_schema = streamed.schema(); + Self { + schema, + on_streamed, + join_type, + operator, + streamed_schema, + streamed, + buffered_side, + state, + sort_option, + join_metrics, + batch_process_state: BatchProcessState::new(), + batch_size, + } + } + + fn poll_next_impl( + &mut self, + cx: &mut std::task::Context<'_>, + ) -> Poll<Option<Result<RecordBatch>>> { + loop { + return match self.state { + PiecewiseMergeJoinStreamState::WaitBufferedSide => { + handle_state!(ready!(self.collect_buffered_side(cx))) + } + PiecewiseMergeJoinStreamState::FetchStreamBatch => { + handle_state!(ready!(self.fetch_stream_batch(cx))) + } + PiecewiseMergeJoinStreamState::ProcessStreamBatch(_) => { + handle_state!(self.process_stream_batch()) + } + PiecewiseMergeJoinStreamState::ExhaustedStreamSide => { + handle_state!(self.process_unmatched_buffered_batch()) + } + PiecewiseMergeJoinStreamState::Completed => Poll::Ready(None), + }; + } + } + + // Collects buffered side data + fn collect_buffered_side( + &mut self, + cx: &mut std::task::Context<'_>, + ) -> Poll<Result<StatefulStreamResult<Option<RecordBatch>>>> { + let build_timer = self.join_metrics.build_time.timer(); + let buffered_data = ready!(self + .buffered_side + .try_as_initial_mut()? + .buffered_fut + .get_shared(cx))?; + build_timer.done(); + + // We will start fetching stream batches for classic joins + self.state = PiecewiseMergeJoinStreamState::FetchStreamBatch; + + self.buffered_side = + BufferedSide::Ready(BufferedSideReadyState { buffered_data }); + + Poll::Ready(Ok(StatefulStreamResult::Continue)) + } + + // Fetches incoming stream batches + fn fetch_stream_batch( + &mut self, + cx: &mut std::task::Context<'_>, + ) -> Poll<Result<StatefulStreamResult<Option<RecordBatch>>>> { + match ready!(self.streamed.poll_next_unpin(cx)) { + None => { + self.state = PiecewiseMergeJoinStreamState::ExhaustedStreamSide; + } + Some(Ok(batch)) => { + // Evaluate the streamed physical expression on the stream batch + let stream_values: ArrayRef = self + .on_streamed + .evaluate(&batch)? + .into_array(batch.num_rows())?; + + self.join_metrics.input_batches.add(1); + self.join_metrics.input_rows.add(batch.num_rows()); + + // Sort stream values and change the streamed record batch accordingly + let indices = sort_to_indices( + stream_values.as_ref(), + Some(self.sort_option), + None, + )?; + let stream_batch = take_record_batch(&batch, &indices)?; + let stream_values = take(stream_values.as_ref(), &indices, None)?; + + self.state = + PiecewiseMergeJoinStreamState::ProcessStreamBatch(StreamedBatch { + batch: stream_batch, + values: vec![stream_values], + }); + } + Some(Err(err)) => return Poll::Ready(Err(err)), + }; + + Poll::Ready(Ok(StatefulStreamResult::Continue)) + } + + // Only classic join will call. This function will process stream batches and evaluate against + // the buffered side data. + fn process_stream_batch( + &mut self, + ) -> Result<StatefulStreamResult<Option<RecordBatch>>> { + let buffered_side = self.buffered_side.try_as_ready_mut()?; + let stream_batch = self.state.try_as_process_stream_batch_mut()?; + + let batch = resolve_classic_join( + buffered_side, + stream_batch, + Arc::clone(&self.schema), + self.operator, + self.sort_option, + self.join_type, + &mut self.batch_process_state, + self.batch_size, + )?; + + if self.batch_process_state.continue_process { + return Ok(StatefulStreamResult::Ready(Some(batch))); + } + + self.state = PiecewiseMergeJoinStreamState::FetchStreamBatch; + Ok(StatefulStreamResult::Ready(Some(batch))) + } + + // Process remaining unmatched rows + fn process_unmatched_buffered_batch( + &mut self, + ) -> Result<StatefulStreamResult<Option<RecordBatch>>> { + // Return early for `JoinType::Right` and `JoinType::Inner` + if matches!(self.join_type, JoinType::Right | JoinType::Inner) { + self.state = PiecewiseMergeJoinStreamState::Completed; + return Ok(StatefulStreamResult::Ready(None)); + } + + let timer = self.join_metrics.join_time.timer(); + + let buffered_data = + Arc::clone(&self.buffered_side.try_as_ready().unwrap().buffered_data); + + // Check if the same batch needs to be checked for values again + if let Some(start_idx) = self.batch_process_state.process_rest { + if let Some(buffered_indices) = &self.batch_process_state.buffered_indices { + let remaining = buffered_indices.len() - start_idx; + + // Branch into this and return value if there are more rows to deal with + if remaining > self.batch_size { + let buffered_batch = buffered_data.batch(); + let empty_stream_batch = + RecordBatch::new_empty(Arc::clone(&self.streamed_schema)); + + let buffered_chunk_ref = + buffered_indices.slice(start_idx, self.batch_size); + let new_buffered_indices = buffered_chunk_ref + .as_any() + .downcast_ref::<UInt64Array>() + .expect("downcast to UInt64Array after slice"); + + let streamed_indices: UInt32Array = + (0..new_buffered_indices.len() as u32).collect(); + + let batch = build_matched_indices( + Arc::clone(&self.schema), + &empty_stream_batch, + buffered_batch, + streamed_indices, + new_buffered_indices.clone(), + )?; + + self.batch_process_state + .set_process_rest(Some(start_idx + self.batch_size)); + self.batch_process_state.continue_process = true; + + return Ok(StatefulStreamResult::Ready(Some(batch))); + } + + let buffered_batch = buffered_data.batch(); + let empty_stream_batch = + RecordBatch::new_empty(Arc::clone(&self.streamed_schema)); + + let buffered_chunk_ref = buffered_indices.slice(start_idx, remaining); + let new_buffered_indices = buffered_chunk_ref + .as_any() + .downcast_ref::<UInt64Array>() + .expect("downcast to UInt64Array after slice"); + + let streamed_indices: UInt32Array = + (0..new_buffered_indices.len() as u32).collect(); + + let batch = build_matched_indices( + Arc::clone(&self.schema), + &empty_stream_batch, + buffered_batch, + streamed_indices, + new_buffered_indices.clone(), + )?; + + self.batch_process_state.reset(); + + timer.done(); + self.join_metrics.output_batches.add(1); + self.state = PiecewiseMergeJoinStreamState::Completed; + + return Ok(StatefulStreamResult::Ready(Some(batch))); + } + + return exec_err!("Batch process state should hold buffered indices"); + } + + let (buffered_indices, streamed_indices) = get_final_indices_from_shared_bitmap( + &buffered_data.visited_indices_bitmap, + self.join_type, + true, + ); + + // If the output indices is larger than the limit for the incremental batching then + // proceed to outputting all matches up to that index, return batch, and the matching + // will start next on the updated index (`process_rest`) + if buffered_indices.len() > self.batch_size { + let buffered_batch = buffered_data.batch(); + let empty_stream_batch = + RecordBatch::new_empty(Arc::clone(&self.streamed_schema)); + + let indices_chunk_ref = buffered_indices + .slice(self.batch_process_state.start_idx, self.batch_size); + + let indices_chunk = indices_chunk_ref + .as_any() + .downcast_ref::<UInt64Array>() + .expect("downcast to UInt64Array after slice"); + + let batch = build_matched_indices( + Arc::clone(&self.schema), + &empty_stream_batch, + buffered_batch, + streamed_indices, + indices_chunk.clone(), + )?; + + self.batch_process_state.buffered_indices = Some(buffered_indices); + self.batch_process_state + .set_process_rest(Some(self.batch_size)); + self.batch_process_state.continue_process = true; + + return Ok(StatefulStreamResult::Ready(Some(batch))); + } + + let buffered_batch = buffered_data.batch(); + let empty_stream_batch = + RecordBatch::new_empty(Arc::clone(&self.streamed_schema)); + + let batch = build_matched_indices( + Arc::clone(&self.schema), + &empty_stream_batch, + buffered_batch, + streamed_indices, + buffered_indices, + )?; + + timer.done(); + self.join_metrics.output_batches.add(1); + self.state = PiecewiseMergeJoinStreamState::Completed; + + Ok(StatefulStreamResult::Ready(Some(batch))) + } +} + +// Holds all information for processing incremental output Review Comment: No i was planning on doing this in a follow up, should this instead be tackled in this pull request? -- This is an automated message from the Apache Git Service. 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