jonathanc-n commented on code in PR #18392:
URL: https://github.com/apache/datafusion/pull/18392#discussion_r2479728047
##########
datafusion/physical-optimizer/src/join_selection.rs:
##########
@@ -256,59 +256,75 @@ fn statistical_join_selection_subrule(
collect_threshold_byte_size: usize,
collect_threshold_num_rows: usize,
) -> Result<Transformed<Arc<dyn ExecutionPlan>>> {
- let transformed =
- if let Some(hash_join) = plan.as_any().downcast_ref::<HashJoinExec>() {
- match hash_join.partition_mode() {
- PartitionMode::Auto => try_collect_left(
- hash_join,
- false,
- collect_threshold_byte_size,
- collect_threshold_num_rows,
- )?
+ let transformed = if let Some(hash_join) =
+ plan.as_any().downcast_ref::<HashJoinExec>()
+ {
+ match hash_join.partition_mode() {
+ PartitionMode::Auto => try_collect_left(
+ hash_join,
+ false,
+ collect_threshold_byte_size,
+ collect_threshold_num_rows,
+ )?
+ .map_or_else(
+ || partitioned_hash_join(hash_join).map(Some),
+ |v| Ok(Some(v)),
+ )?,
+ PartitionMode::CollectLeft => try_collect_left(hash_join, true, 0,
0)?
.map_or_else(
|| partitioned_hash_join(hash_join).map(Some),
|v| Ok(Some(v)),
)?,
- PartitionMode::CollectLeft => try_collect_left(hash_join,
true, 0, 0)?
- .map_or_else(
- || partitioned_hash_join(hash_join).map(Some),
- |v| Ok(Some(v)),
- )?,
- PartitionMode::Partitioned => {
- let left = hash_join.left();
- let right = hash_join.right();
- if hash_join.join_type().supports_swap()
- && should_swap_join_order(&**left, &**right)?
- {
- hash_join
- .swap_inputs(PartitionMode::Partitioned)
- .map(Some)?
- } else {
- None
- }
+ PartitionMode::Partitioned => {
+ let left = hash_join.left();
+ let right = hash_join.right();
+ if hash_join.join_type().supports_swap()
+ && should_swap_join_order(&**left, &**right)?
+ {
+ hash_join
+ .swap_inputs(PartitionMode::Partitioned)
+ .map(Some)?
+ } else {
+ None
}
}
- } else if let Some(cross_join) =
plan.as_any().downcast_ref::<CrossJoinExec>() {
- let left = cross_join.left();
- let right = cross_join.right();
- if should_swap_join_order(&**left, &**right)? {
- cross_join.swap_inputs().map(Some)?
- } else {
- None
- }
- } else if let Some(nl_join) =
plan.as_any().downcast_ref::<NestedLoopJoinExec>() {
- let left = nl_join.left();
- let right = nl_join.right();
- if nl_join.join_type().supports_swap()
- && should_swap_join_order(&**left, &**right)?
- {
- nl_join.swap_inputs().map(Some)?
- } else {
- None
- }
+ }
+ } else if let Some(cross_join) =
plan.as_any().downcast_ref::<CrossJoinExec>() {
+ let left = cross_join.left();
+ let right = cross_join.right();
+ if should_swap_join_order(&**left, &**right)? {
+ cross_join.swap_inputs().map(Some)?
} else {
None
- };
+ }
+ } else if let Some(nl_join) =
plan.as_any().downcast_ref::<NestedLoopJoinExec>() {
+ let left = nl_join.left();
+ let right = nl_join.right();
+ if nl_join.join_type().supports_swap()
+ && should_swap_join_order(&**left, &**right)?
+ {
+ nl_join.swap_inputs().map(Some)?
+ } else {
+ None
+ }
+ } else if let Some(pwmj) =
plan.as_any().downcast_ref::<PiecewiseMergeJoinExec>() {
+ let left = pwmj.buffered();
+ let right = pwmj.streamed();
+ if pwmj.join_type().supports_swap()
+ // Put ! here because should_swap_join_order returns true if
left > right but
+ // PiecewiseMergeJoin wants the left side to be the larger
one, so only swap if
+ // left < right
+ && (!should_swap_join_order(&**left, &**right)?
+ || matches!(pwmj.join_type(), JoinType::RightSemi |
JoinType::RightAnti))
Review Comment:
LeftSemi and Left Anti do not swap and only right existence joins do. This
is explained above `swap_inputs` in PiecewiseMergeJoinExec
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/exec.rs:
##########
@@ -291,34 +299,19 @@ impl PiecewiseMergeJoinExec {
on: (Arc<dyn PhysicalExpr>, Arc<dyn PhysicalExpr>),
operator: Operator,
join_type: JoinType,
- num_partitions: usize,
) -> Result<Self> {
- // TODO: Implement existence joins for PiecewiseMergeJoin
- if is_existence_join(join_type) {
- return not_impl_err!(
- "Existence Joins are currently not supported for
PiecewiseMergeJoin"
- );
- }
+ let buffered_partitions =
buffered.output_partitioning().partition_count();
+ let streamed_partitions =
streamed.output_partitioning().partition_count();
// Take the operator and enforce a sort order on the streamed +
buffered side based on
// the operator type.
let sort_options = match operator {
Operator::Lt | Operator::LtEq => {
// For left existence joins the inputs will be swapped so the
sort
// options are switched
- if is_right_existence_join(join_type) {
- SortOptions::new(false, true)
- } else {
- SortOptions::new(true, true)
- }
- }
- Operator::Gt | Operator::GtEq => {
- if is_right_existence_join(join_type) {
- SortOptions::new(true, true)
- } else {
- SortOptions::new(false, true)
- }
+ SortOptions::new(true, true)
Review Comment:
This was changed because for whatever reason I had thought that swapping
happened before join creation :laughing:
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/classic_join.rs:
##########
@@ -40,19 +40,19 @@ 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 {
+pub(super) enum ClassicPWMJStreamState {
Review Comment:
Renamed to make it more distinct between Existence join streamstate and
Classic join stream state.
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/existence_join.rs:
##########
@@ -0,0 +1,1062 @@
+// 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.
+
+//! Implementation for PiecewiseMergeJoin's Existence Join (Left, Right, Full,
Inner)
+
+use arrow::array::Array;
+use arrow::array::{ArrayRef, RecordBatch};
+use arrow::compute::BatchCoalescer;
+use arrow_schema::{Schema, SchemaRef, SortOptions};
+use datafusion_common::NullEquality;
+use datafusion_common::{internal_err, Result};
+use datafusion_execution::{RecordBatchStream, SendableRecordBatchStream};
+use datafusion_expr::Accumulator;
+use datafusion_expr::{JoinType, Operator};
+use datafusion_functions_aggregate_common::min_max::{MaxAccumulator,
MinAccumulator};
+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::utils::compare_join_arrays;
+use crate::joins::utils::{BuildProbeJoinMetrics, StatefulStreamResult};
+
+pub(super) enum ExistencePWMJStreamState {
+ CollectBufferedSide,
+ FetchAndProcessStreamBatch,
+ ProcessMatched,
+ Completed,
+}
+
+pub(crate) struct ExistencePWMJStream {
+ // 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,
+ // Buffered side data
+ buffered_side: BufferedSide,
+ // Tracks the state of the `PiecewiseMergeJoin`
+ state: ExistencePWMJStreamState,
+ // Metrics for build + probe joins
+ join_metrics: BuildProbeJoinMetrics,
+ // Tracking incremental state for emitting record batches
+ batch_process_state: BatchProcessState,
+}
+
+impl RecordBatchStream for ExistencePWMJStream {
+ fn schema(&self) -> SchemaRef {
+ Arc::clone(&self.schema)
+ }
+}
+
+// `ExistencePWMJStreamState` is separated into `CollectBufferedSide`,
`FetchAndProcessStreamBatch`,
Review Comment:
Read the main logic here, after the min//max value is found for the streamed
side, then the buffered side is probed. After it finds the first match it will
emit all rows from `matched_idx - buffered_batch_length` for Semi joins
(matches) and `0 - matched_idx` for anti joins (non-matches)
You can refer back to the `PiecewiseMergeJoinExec` docs if need a refresher.
##########
datafusion/physical-optimizer/src/join_selection.rs:
##########
@@ -256,59 +256,75 @@ fn statistical_join_selection_subrule(
collect_threshold_byte_size: usize,
collect_threshold_num_rows: usize,
) -> Result<Transformed<Arc<dyn ExecutionPlan>>> {
- let transformed =
- if let Some(hash_join) = plan.as_any().downcast_ref::<HashJoinExec>() {
- match hash_join.partition_mode() {
- PartitionMode::Auto => try_collect_left(
- hash_join,
- false,
- collect_threshold_byte_size,
- collect_threshold_num_rows,
- )?
+ let transformed = if let Some(hash_join) =
Review Comment:
I don't know why these showed a diff but there isn't anything different here
except for the addition of the PiecewiseMergeJoin branch for swapping.
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/exec.rs:
##########
@@ -462,9 +446,35 @@ impl PiecewiseMergeJoinExec {
}
}
- // TODO
+ // Inner, Outer, Left, Right joins are swapped so that left side is larger
than right
+ // Left Semi/Anti joins are not swapped while Right Semi/Anti joins are
always swapped. This
Review Comment:
This will explain the logic for why only Right semi/anti joins are swapped.
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/exec.rs:
##########
@@ -493,18 +503,13 @@ impl ExecutionPlan for PiecewiseMergeJoinExec {
}
fn required_input_ordering(&self) -> Vec<Option<OrderingRequirements>> {
- // Existence joins don't need to be sorted on one side.
- if is_right_existence_join(self.join_type) {
- unimplemented!()
- } else {
- // Sort the right side in memory, so we do not need to enforce any
sorting
- vec![
- Some(OrderingRequirements::from(
- self.left_child_plan_required_order.clone(),
- )),
- None,
- ]
- }
+ // Sort the right side in memory, so we do not need to enforce any
sorting
Review Comment:
```suggestion
// The left side is sorted for classic and existence joins.
// For classic joins, the right side is sorted in memory so there is
no need to sort
```
##########
datafusion/physical-plan/src/joins/piecewise_merge_join/exec.rs:
##########
@@ -339,13 +330,6 @@ impl PiecewiseMergeJoinExec {
"PiecewiseMergeJoinExec requires valid sort expressions for
its left side"
);
};
- let Some(right_batch_required_orders) =
Review Comment:
No longer needed, only the left side needs to be sorted.
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