Struct NetworkCoalesceExec 

pub struct NetworkCoalesceExec { /* private fields */ }

ExecutionPlan that coalesces partitions from multiple tasks into a one or more task without performing any repartition, and maintaining the same partitioning scheme.

This is the equivalent of a [CoalescePartitionsExec] but coalescing tasks across the network between distributed stages.

                               ┌───────────────────────────┐                                   ■
                               │    NetworkCoalesceExec    │                                   │
                               │         (task 1)          │                                   │
                               └┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬┘                                Stage N+1
                                │1││2││3││4││5││6││7││8││9│                                    │
                                └─┘└─┘└─┘└─┘└─┘└─┘└─┘└─┘└─┘                                    │
                                ▲  ▲  ▲   ▲  ▲  ▲   ▲  ▲  ▲                                    ■
  ┌──┬──┬───────────────────────┴──┴──┘   │  │  │   └──┴──┴──────────────────────┬──┬──┐
  │  │  │                                 │  │  │                                │  │  │       ■
 ┌─┐┌─┐┌─┐                               ┌─┐┌─┐┌─┐                              ┌─┐┌─┐┌─┐      │
 │1││2││3│                               │4││5││6│                              │7││8││9│      │
┌┴─┴┴─┴┴─┴──────────────────┐  ┌─────────┴─┴┴─┴┴─┴─────────┐ ┌──────────────────┴─┴┴─┴┴─┴┐  Stage N
│  Arc<dyn ExecutionPlan>   │  │  Arc<dyn ExecutionPlan>   │ │  Arc<dyn ExecutionPlan>   │     │
│         (task 1)          │  │         (task 2)          │ │         (task 3)          │     │
└───────────────────────────┘  └───────────────────────────┘ └───────────────────────────┘     ■

The communication between two stages across a NetworkCoalesceExec has two implications:

• Stage N+1 may have one or more tasks. Each consumer task reads a contiguous group of upstream tasks from Stage N.
• Output partitioning for Stage N+1 is sized based on the maximum upstream-group size. When groups are uneven, consumer tasks with smaller groups return empty streams for the “extra” partitions.

                   ┌───────────────────────────┐        ┌───────────────────────────┐          ■
                   │    NetworkCoalesceExec    │        │    NetworkCoalesceExec    │          │
                   │         (task 1)          │        │         (task 2)          │          │
                   └┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬─────────┘        └┬─┬┬─┬┬─┬┬─┬┬─┬┬─┬─────────┘       Stage N+1
                    │1││2││3││4││5││6│                   │7││8││9││_││_││_│                    │
                    └─┘└─┘└─┘└─┘└─┘└─┘                   └─┘└─┘└─┘└─┘└─┘└─┘                    │
                     ▲  ▲  ▲  ▲  ▲  ▲                     ▲  ▲  ▲                              ■
  ┌──┬──┬────────────┴──┴──┘  └──┴──┴─────┬──┬──┐         └──┴──┴────────────────┬──┬──┐
  │  │  │                                 │  │  │                                │  │  │       ■
 ┌─┐┌─┐┌─┐                               ┌─┐┌─┐┌─┐                              ┌─┐┌─┐┌─┐      │
 │1││2││3│                               │4││5││6│                              │7││8││9│      │
┌┴─┴┴─┴┴─┴──────────────────┐  ┌─────────┴─┴┴─┴┴─┴─────────┐ ┌──────────────────┴─┴┴─┴┴─┴┐  Stage N
│  Arc<dyn ExecutionPlan>   │  │  Arc<dyn ExecutionPlan>   │ │  Arc<dyn ExecutionPlan>   │     │
│         (task 1)          │  │         (task 2)          │ │         (task 3)          │     │
└───────────────────────────┘  └───────────────────────────┘ └───────────────────────────┘     ■

This node has two variants.

1. Pending: acts as a placeholder for the distributed optimization step to mark it as ready.
2. Ready: runs within a distributed stage and queries the next input stage over the network using Arrow Flight.

Implementations

impl NetworkCoalesceExec

pub fn try_new( input: Arc<dyn ExecutionPlan>, query_id: Uuid, num: usize, task_count: usize, input_task_count: usize, ) -> Result<Self>

Builds a new NetworkCoalesceExec in “Pending” state.

Typically, this node should be placed right after nodes that coalesce all the input partitions into one, for example:

• [CoalescePartitionsExec]
• [SortPreservingMergeExec]

Trait Implementations

impl Clone for NetworkCoalesceExec

fn clone(&self) -> NetworkCoalesceExec

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NetworkCoalesceExec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl DisplayAs for NetworkCoalesceExec

fn fmt_as(&self, _t: DisplayFormatType, f: &mut Formatter<'_>) -> Result

Format according to DisplayFormatType, used when verbose representation looks different from the default one

impl ExecutionPlan for NetworkCoalesceExec

fn name(&self) -> &str

Short name for the ExecutionPlan, such as ‘DataSourceExec’.

fn as_any(&self) -> &dyn Any

Returns the execution plan as Any so that it can be downcast to a specific implementation.

fn properties(&self) -> &Arc<PlanProperties>

Return properties of the output of the ExecutionPlan, such as output ordering(s), partitioning information etc.

fn children(&self) -> Vec<&Arc<dyn ExecutionPlan>>

Get a list of children ExecutionPlans that act as inputs to this plan. The returned list will be empty for leaf nodes such as scans, will contain a single value for unary nodes, or two values for binary nodes (such as joins).

fn with_new_children( self: Arc<Self>, children: Vec<Arc<dyn ExecutionPlan>>, ) -> Result<Arc<dyn ExecutionPlan>>

Returns a new ExecutionPlan where all existing children were replaced by the children, in order

fn execute( &self, partition: usize, context: Arc<TaskContext>, ) -> Result<SendableRecordBatchStream>

Begin execution of partition, returning a Stream of RecordBatches.

fn metrics(&self) -> Option<MetricsSet>

Return a snapshot of the set of Metrics for this ExecutionPlan. If no Metrics are available, return None.

fn static_name() -> &'static str

where Self: Sized,

Short name for the ExecutionPlan, such as ‘DataSourceExec’. Like name but can be called without an instance.

fn schema(&self) -> Arc<Schema>

Get the schema for this execution plan

fn check_invariants(&self, check: InvariantLevel) -> Result<(), DataFusionError>

Returns an error if this individual node does not conform to its invariants. These invariants are typically only checked in debug mode.

fn required_input_distribution(&self) -> Vec<Distribution>

Specifies the data distribution requirements for all the children for this ExecutionPlan, By default it’s [Distribution::UnspecifiedDistribution] for each child,

fn required_input_ordering(&self) -> Vec<Option<OrderingRequirements>>

Specifies the ordering required for all of the children of this ExecutionPlan.

fn maintains_input_order(&self) -> Vec<bool>

Returns false if this ExecutionPlan’s implementation may reorder rows within or between partitions.

fn benefits_from_input_partitioning(&self) -> Vec<bool>

Specifies whether the ExecutionPlan benefits from increased parallelization at its input for each child.

fn reset_state( self: Arc<Self>, ) -> Result<Arc<dyn ExecutionPlan>, DataFusionError>

Reset any internal state within this ExecutionPlan.

fn repartitioned( &self, _target_partitions: usize, _config: &ConfigOptions, ) -> Result<Option<Arc<dyn ExecutionPlan>>, DataFusionError>

If supported, attempt to increase the partitioning of this ExecutionPlan to produce target_partitions partitions.

fn partition_statistics( &self, partition: Option<usize>, ) -> Result<Statistics, DataFusionError>

Returns statistics for a specific partition of this ExecutionPlan node. If statistics are not available, should return Statistics::new_unknown (the default), not an error. If partition is None, it returns statistics for the entire plan.

fn supports_limit_pushdown(&self) -> bool

Returns true if a limit can be safely pushed down through this ExecutionPlan node.

fn with_fetch(&self, _limit: Option<usize>) -> Option<Arc<dyn ExecutionPlan>>

Returns a fetching variant of this ExecutionPlan node, if it supports fetch limits. Returns None otherwise.

fn fetch(&self) -> Option<usize>

Gets the fetch count for the operator, None means there is no fetch.

fn cardinality_effect(&self) -> CardinalityEffect

Gets the effect on cardinality, if known

fn try_swapping_with_projection( &self, _projection: &ProjectionExec, ) -> Result<Option<Arc<dyn ExecutionPlan>>, DataFusionError>

Attempts to push down the given projection into the input of this ExecutionPlan.

fn gather_filters_for_pushdown( &self, _phase: FilterPushdownPhase, parent_filters: Vec<Arc<dyn PhysicalExpr>>, _config: &ConfigOptions, ) -> Result<FilterDescription, DataFusionError>

Collect filters that this node can push down to its children. Filters that are being pushed down from parents are passed in, and the node may generate additional filters to push down. For example, given the plan FilterExec -> HashJoinExec -> DataSourceExec, what will happen is that we recurse down the plan calling ExecutionPlan::gather_filters_for_pushdown:

fn handle_child_pushdown_result( &self, _phase: FilterPushdownPhase, child_pushdown_result: ChildPushdownResult, _config: &ConfigOptions, ) -> Result<FilterPushdownPropagation<Arc<dyn ExecutionPlan>>, DataFusionError>

Handle the result of a child pushdown.

fn with_new_state( &self, _state: Arc<dyn Any + Send + Sync>, ) -> Option<Arc<dyn ExecutionPlan>>

Injects arbitrary run-time state into this execution plan, returning a new plan instance that incorporates that state if it is relevant to the concrete node implementation.

fn try_pushdown_sort( &self, _order: &[PhysicalSortExpr], ) -> Result<SortOrderPushdownResult<Arc<dyn ExecutionPlan>>, DataFusionError>

Try to push down sort ordering requirements to this node.

fn with_preserve_order( &self, _preserve_order: bool, ) -> Option<Arc<dyn ExecutionPlan>>

Returns a variant of this ExecutionPlan that is aware of order-sensitivity.

impl NetworkBoundary for NetworkCoalesceExec

fn input_stage(&self) -> &Stage

Returns the assigned input Stage, if any.

fn with_input_stage(&self, input_stage: Stage) -> Result<Arc<dyn ExecutionPlan>>

Called when a Stage is correctly formed. The NetworkBoundary can use this information to perform any internal transformations necessary for distributed execution.