kosiew commented on code in PR #21666:
URL: https://github.com/apache/datafusion/pull/21666#discussion_r3117320962
##########
datafusion/physical-plan/src/joins/hash_join/stream.rs:
##########
@@ -421,6 +424,49 @@ impl HashJoinStream {
}
}
+ /// Transitions state after build-side data has been collected,
automatically
+ /// reporting build data to the accumulator when one is present.
+ ///
+ /// If a `build_accumulator` is configured, this method constructs the
+ /// appropriate [`PartitionBuildData`], schedules the reporting future, and
+ /// returns [`HashJoinStreamState::WaitPartitionBoundsReport`]. Otherwise
it
+ /// delegates to [`Self::state_after_build_ready`].
+ fn transition_after_build_collected(
+ &mut self,
+ left_data: &Arc<JoinLeftData>,
+ ) -> HashJoinStreamState {
+ let Some(build_accumulator) = self.build_accumulator.as_ref() else {
+ return Self::state_after_build_ready(self.join_type,
left_data.as_ref());
+ };
+
+ let pushdown = left_data.membership().clone();
+ let bounds = left_data
+ .bounds
+ .clone()
+ .unwrap_or_else(|| PartitionBounds::new(vec![]));
+
+ let build_data = match self.mode {
+ PartitionMode::Partitioned => PartitionBuildData::Partitioned {
+ partition_id: self.partition,
+ pushdown,
+ bounds,
+ },
+ PartitionMode::CollectLeft => {
+ PartitionBuildData::CollectLeft { pushdown, bounds }
+ }
+ PartitionMode::Auto => unreachable!(
+ "PartitionMode::Auto should not be present at execution time.
This is a bug in DataFusion, please report it!"
+ ),
+ };
+
+ let acc = Arc::clone(build_accumulator);
+ self.build_waiter = Some(OnceFut::new(async move {
+ acc.report_build_data(build_data).await
+ }));
+ self.build_reported = true;
Review Comment:
I think there is still a race here. `build_reported` gets flipped as soon as
the `OnceFut` is created, but the future is lazy and only runs once
`wait_for_partition_bounds_report()` actually polls it.
If a parent drops this stream after `transition_after_build_collected()`
returns, but before the waiter is ever polled, `Drop` will skip
`report_canceled_partition()` even though nothing was delivered to the
coordinator. That feels like it recreates the original hang, just in a narrower
timing window.
Would it make sense to only mark this as reported after the waiter completes
successfully? Alternatively, maybe replace the bool with a small lifecycle
state so `Drop` can still cancel something that was only scheduled but never
observed.
##########
datafusion/physical-plan/src/joins/hash_join/shared_bounds.rs:
##########
@@ -358,229 +397,283 @@ impl SharedBuildAccumulator {
/// # Returns
/// * `Result<()>` - Ok if successful, Err if filter update failed or mode
mismatch
pub(crate) async fn report_build_data(&self, data: PartitionBuildData) ->
Result<()> {
- // Store data in the accumulator
- {
+ let finalize_input = {
let mut guard = self.inner.lock();
+ self.store_build_data(&mut guard, data)?;
+ self.take_finalize_input_if_ready(&mut guard)
+ };
- match (data, &mut *guard) {
- // Partitioned mode
- (
- PartitionBuildData::Partitioned {
- partition_id,
- pushdown,
- bounds,
- },
- AccumulatedBuildData::Partitioned { partitions },
- ) => {
- partitions[partition_id] = Some(PartitionData { pushdown,
bounds });
- }
- // CollectLeft mode (store once, deduplicate across partitions)
- (
- PartitionBuildData::CollectLeft { pushdown, bounds },
- AccumulatedBuildData::CollectLeft { data },
- ) => {
- // Deduplicate - all partitions report the same data in
CollectLeft
- if data.is_none() {
- *data = Some(PartitionData { pushdown, bounds });
- }
+ if let Some(finalize_input) = finalize_input {
+ self.finish(finalize_input);
+ }
+
+ self.wait_for_completion().await
+ }
+
+ pub(crate) fn report_canceled_partition(&self, partition_id: usize) {
+ let finalize_input = {
+ let mut guard = self.inner.lock();
+ self.store_canceled_partition(&mut guard, partition_id);
+ self.take_finalize_input_if_ready(&mut guard)
+ };
+
+ if let Some(finalize_input) = finalize_input {
+ self.finish(finalize_input);
+ }
+ }
+
+ fn store_build_data(
+ &self,
+ guard: &mut AccumulatorState,
+ data: PartitionBuildData,
+ ) -> Result<()> {
+ match (data, &mut guard.data) {
+ (
+ PartitionBuildData::Partitioned {
+ partition_id,
+ pushdown,
+ bounds,
+ },
+ AccumulatedBuildData::Partitioned {
+ partitions,
+ completed_partitions,
+ },
+ ) => {
+ if matches!(partitions[partition_id],
PartitionStatus::Pending) {
+ *completed_partitions += 1;
}
- // Mismatched modes - should never happen
- _ => {
- return datafusion_common::internal_err!(
- "Build data mode mismatch in report_build_data"
- );
+ partitions[partition_id] =
+ PartitionStatus::Reported(PartitionData { pushdown, bounds
});
+ }
+ (
+ PartitionBuildData::CollectLeft { pushdown, bounds },
+ AccumulatedBuildData::CollectLeft {
+ data,
+ reported_count,
+ ..
+ },
+ ) => {
+ if matches!(data, PartitionStatus::Pending) {
+ *data = PartitionStatus::Reported(PartitionData {
pushdown, bounds });
}
+ *reported_count += 1;
+ }
+ _ => {
+ return datafusion_common::internal_err!(
+ "Build data mode mismatch in report_build_data"
+ );
}
}
+ Ok(())
+ }
- // Wait for all partitions to report
- if self.barrier.wait().await.is_leader() {
- // All partitions have reported, so we can create and update the
filter
- let inner = self.inner.lock();
-
- match &*inner {
- // CollectLeft: Simple conjunction of bounds and membership
check
- AccumulatedBuildData::CollectLeft { data } => {
- if let Some(partition_data) = data {
- // Create membership predicate (InList for small build
sides, hash lookup otherwise)
- let membership_expr = create_membership_predicate(
- &self.on_right,
- partition_data.pushdown.clone(),
- &HASH_JOIN_SEED,
- self.probe_schema.as_ref(),
- )?;
-
- // Create bounds check expression (if bounds available)
- let bounds_expr = create_bounds_predicate(
- &self.on_right,
- &partition_data.bounds,
- );
-
- // Combine membership and bounds expressions for
multi-layer optimization:
- // - Bounds (min/max): Enable statistics-based pruning
(Parquet row group/file skipping)
- // - Membership (InList/hash lookup): Enables:
- // * Precise filtering (exact value matching)
- // * Bloom filter utilization (if present in Parquet
files)
- // * Better pruning for data types where min/max
isn't effective (e.g., UUIDs)
- // Together, they provide complementary benefits and
maximize data skipping.
- // Only update the filter if we have something to push
down
- if let Some(filter_expr) = match (membership_expr,
bounds_expr) {
- (Some(membership), Some(bounds)) => {
- // Both available: combine with AND
- Some(Arc::new(BinaryExpr::new(
- bounds,
- Operator::And,
- membership,
- ))
- as Arc<dyn PhysicalExpr>)
- }
- (Some(membership), None) => {
- // Membership available but no bounds
- // This is reachable when we have data but
bounds aren't available
- // (e.g., unsupported data types or no columns
with bounds)
- Some(membership)
- }
- (None, Some(bounds)) => {
- // Bounds available but no membership.
- // This should be unreachable in practice: we
can always push down a reference
- // to the hash table.
- // But it seems safer to handle it defensively.
- Some(bounds)
- }
- (None, None) => {
- // No filter available (e.g., empty build side)
- // Don't update the filter, but continue to
mark complete
- None
- }
- } {
- self.dynamic_filter.update(filter_expr)?;
- }
+ fn store_canceled_partition(
+ &self,
+ guard: &mut AccumulatorState,
+ partition_id: usize,
+ ) {
+ if let AccumulatedBuildData::Partitioned {
+ partitions,
+ completed_partitions,
+ } = &mut guard.data
+ && matches!(partitions[partition_id], PartitionStatus::Pending)
+ {
+ partitions[partition_id] = PartitionStatus::CanceledUnknown;
+ *completed_partitions += 1;
+ }
+ }
+
+ fn take_finalize_input_if_ready(
+ &self,
+ guard: &mut AccumulatorState,
+ ) -> Option<FinalizeInput> {
+ if !matches!(guard.completion, CompletionState::Pending) {
+ return None;
+ }
+
+ let finalize_input = match &guard.data {
+ AccumulatedBuildData::Partitioned {
+ partitions,
+ completed_partitions,
+ } if *completed_partitions == partitions.len() => {
+ Some(FinalizeInput::Partitioned(partitions.clone()))
+ }
+ AccumulatedBuildData::CollectLeft {
+ data,
+ reported_count,
+ expected_reports,
+ } if *reported_count == *expected_reports => {
+ Some(FinalizeInput::CollectLeft(data.clone()))
+ }
+ _ => None,
+ }?;
+
+ guard.completion = CompletionState::Finalizing;
+ Some(finalize_input)
+ }
+
+ fn finish(&self, finalize_input: FinalizeInput) {
+ let result = self.build_filter(finalize_input).map_err(Arc::new);
+ self.dynamic_filter.mark_complete();
+
+ let mut guard = self.inner.lock();
+ guard.completion = CompletionState::Ready(result);
+ drop(guard);
+ self.completion_notify.notify_waiters();
+ }
+
+ async fn wait_for_completion(&self) -> Result<()> {
+ loop {
+ let notified = {
+ let guard = self.inner.lock();
+ match &guard.completion {
+ CompletionState::Ready(Ok(())) => return Ok(()),
+ CompletionState::Ready(Err(err)) => {
+ return Err(DataFusionError::Shared(Arc::clone(err)));
+ }
+ CompletionState::Pending | CompletionState::Finalizing => {
+ self.completion_notify.notified()
}
}
- // Partitioned: CASE expression routing to per-partition
filters
- AccumulatedBuildData::Partitioned { partitions } => {
- // Collect all partition data (should all be Some at this
point)
- let partition_data: Vec<_> =
- partitions.iter().filter_map(|p| p.as_ref()).collect();
-
- if !partition_data.is_empty() {
- // Build a CASE expression that combines range checks
AND membership checks
- // CASE (hash_repartition(join_keys) % num_partitions)
- // WHEN 0 THEN (col >= min_0 AND col <= max_0 AND
...) AND membership_check_0
- // WHEN 1 THEN (col >= min_1 AND col <= max_1 AND
...) AND membership_check_1
- // ...
- // ELSE false
- // END
-
- let num_partitions = partition_data.len();
-
- // Create base expression: hash_repartition(join_keys)
% num_partitions
- let routing_hash_expr = Arc::new(HashExpr::new(
- self.on_right.clone(),
- self.repartition_random_state.clone(),
- "hash_repartition".to_string(),
- ))
- as Arc<dyn PhysicalExpr>;
-
- let modulo_expr = Arc::new(BinaryExpr::new(
- routing_hash_expr,
- Operator::Modulo,
- lit(ScalarValue::UInt64(Some(num_partitions as
u64))),
- ))
- as Arc<dyn PhysicalExpr>;
-
- // Create WHEN branches for each partition
- let when_then_branches: Vec<(
- Arc<dyn PhysicalExpr>,
- Arc<dyn PhysicalExpr>,
- )> = partitions
- .iter()
- .enumerate()
- .filter_map(|(partition_id, partition_opt)| {
- partition_opt.as_ref().and_then(|partition| {
- // Skip empty partitions - they would
always return false anyway
- match &partition.pushdown {
- PushdownStrategy::Empty => None,
- _ => Some((partition_id, partition)),
- }
- })
- })
- .map(|(partition_id, partition)| -> Result<_> {
- // WHEN partition_id
- let when_expr =
- lit(ScalarValue::UInt64(Some(partition_id
as u64)));
-
- // THEN: Combine bounds check AND membership
predicate
-
- // 1. Create membership predicate (InList for
small build sides, hash lookup otherwise)
- let membership_expr =
create_membership_predicate(
- &self.on_right,
- partition.pushdown.clone(),
- &HASH_JOIN_SEED,
- self.probe_schema.as_ref(),
- )?;
-
- // 2. Create bounds check expression for this
partition (if bounds available)
- let bounds_expr = create_bounds_predicate(
- &self.on_right,
- &partition.bounds,
- );
-
- // 3. Combine membership and bounds expressions
- let then_expr = match (membership_expr,
bounds_expr) {
- (Some(membership), Some(bounds)) => {
- // Both available: combine with AND
- Arc::new(BinaryExpr::new(
- bounds,
- Operator::And,
- membership,
- ))
- as Arc<dyn PhysicalExpr>
- }
- (Some(membership), None) => {
- // Membership available but no bounds
(e.g., unsupported data types)
- membership
- }
- (None, Some(bounds)) => {
- // Bounds available but no membership.
- // This should be unreachable in
practice: we can always push down a reference
- // to the hash table.
- // But it seems safer to handle it
defensively.
- bounds
- }
- (None, None) => {
- // No filter for this partition -
should not happen due to filter_map above
- // but handle defensively by returning
a "true" literal
- lit(true)
- }
- };
-
- Ok((when_expr, then_expr))
- })
- .collect::<Result<Vec<_>>>()?;
-
- // Optimize for single partition: skip CASE expression
entirely
- let filter_expr = if when_then_branches.is_empty() {
- // All partitions are empty: no rows can match
- lit(false)
- } else if when_then_branches.len() == 1 {
- // Single partition: just use the condition
directly
- // since hash % 1 == 0 always, the WHEN 0 branch
will always match
- Arc::clone(&when_then_branches[0].1)
- } else {
- // Multiple partitions: create CASE expression
- Arc::new(CaseExpr::try_new(
- Some(modulo_expr),
- when_then_branches,
- Some(lit(false)), // ELSE false
- )?) as Arc<dyn PhysicalExpr>
- };
+ };
+ notified.await;
+ }
+ }
+ fn build_filter(&self, finalize_input: FinalizeInput) -> Result<()> {
+ match finalize_input {
+ FinalizeInput::CollectLeft(partition) => match partition {
+ PartitionStatus::Reported(partition_data) => {
+ let membership_expr = create_membership_predicate(
+ &self.on_right,
+ partition_data.pushdown.clone(),
+ &HASH_JOIN_SEED,
+ self.probe_schema.as_ref(),
+ )?;
+ let bounds_expr =
+ create_bounds_predicate(&self.on_right,
&partition_data.bounds);
+
+ if let Some(filter_expr) = match (membership_expr,
bounds_expr) {
Review Comment:
I noticed the “membership + bounds gives final predicate” logic now exists
in both the `CollectLeft` and `Partitioned` finalize paths, with slightly
different control flow.
It might be worth pulling that into a small helper so both branches stay
aligned as the dynamic filter logic evolves. That would make future changes a
bit safer.
##########
datafusion/physical-plan/src/joins/hash_join/stream.rs:
##########
@@ -219,6 +219,8 @@ pub(super) struct HashJoinStream {
/// Optional future to signal when build information has been reported by
all partitions
/// and the dynamic filter has been updated
build_waiter: Option<OnceFut<()>>,
+ /// Tracks whether this partition has already reported build information
to the coordinator.
Review Comment:
Once the blocking issue above is sorted out, this field might benefit from a
stronger type than just `bool`.
Something like `NotReported`, `ReportScheduled`, and `ReportDelivered` would
make the drop semantics much clearer and help avoid another mix-up between
"scheduled" and "actually seen by the coordinator".
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