Struct BroadcastExec 

pub struct BroadcastExec { /* private fields */ }

ExecutionPlan that scales up partitions for network broadcasting.

This plan takes N input partitions and exposes N*M output partitions, where M is the number of consumer tasks. Each virtual partition i returns the cached result of input partition i % N.

This allows each consumer task to fetch a unique set of partition numbers, the virtual partitions, while all receiving the same data via the actual partitions. This structure maintains the invariant that each partition is executed exactly once by the framework.

Broadcast is used in a 1 to many context, like this:

┌────────────────────────┐      ┌────────────────────────┐                         ┌────────────────────────┐     ■
│  NetworkBroadcastExec  │      │  NetworkBroadcastExec  │           ...           │  NetworkBroadcastExec  │     │
│        (task 1)        │      │        (task 2)        │                         │        (task M)        │ Stage N+1
└┬─┬─────┬───┬───────────┘      └───────┬─┬─────┬────┬───┘                         └─────┬──────┬─────┬────┬┘     │
 │0│     │N-1│                          │N│     │2N-1│                                   │(M-1)N│     │MN-1│      │
 └▲┘ ... └▲──┘                          └▲┘ ... └──▲─┘                                   └───▲──┘ ... └──▲─┘      ■
  │       │     Populates                │         │                                         │           │
  │       └────Cache Index ───┐     Cache Hit   Cache Hit                    ┌──Cache Hit────┘           │
  │                N-1        │      Index 0    Index N-1                    │                           │
  └────Populates ─────┐       │          │         │                         │            ┌───Cache Hit──┘
     Cache Index 0    │       │          │         │                         │            │
                     ┌┴┐ ... ┌┴──┐      ┌┴┐ ... ┌──┴─┐        ...        ┌───┴──┐ ... ┌───┴┐                      ■
                     │0│     │N-1│      │N│     │2N-1│                   │(M-1)N│     │MN-1│                      │
                    ┌┴─┴─────┴───┴──────┴─┴─────┴────┴───────────────────┴──────┴─────┴────┴┐                     │
                    │                             BroadcastExec                             │                     │
                    │                     ┌───────────────────────────┐                     │                     │
                    │                     │        Batch Cache        │                     │                  Stage N
                    │                     │┌─────────┐     ┌─────────┐│                     │                     │
                    │                     ││ index 0 │ ... │index N-1││                     │                     │
                    │                     │└─────────┘     └─────────┘│                     │                     │
                    │                     └───────────────────────────┘                     │                     │
                    └───────────────────────────┬─┬──────────┬───┬──────────────────────────┘                     ■
                                                │0│          │N-1│
                                                └▲┘    ...   └─▲─┘
                                                 │             │
                                              ┌──┘             └──┐
                                              │                   │                                               ■
                                             ┌┴┐       ...     ┌──┴┐                                              │
                                             │0│               │N-1│                                          Stage N-1
                                            ┌┴─┴───────────────┴───┴┐                                             │
                                            │Arc<dyn ExecutionPlan> │                                             │
                                            └───────────────────────┘                                             ■

Notice that the first consumer task, [NetworkBroadcastExec] task 1, triggers the execution of the operator below the [BroadCastExec] and populates each cache index with the respective partition. Subsequent consumer tasks, rather than executing the same partitions, read the data from the cache for each partition.

Implementations

impl BroadcastExec

pub fn new(input: Arc<dyn ExecutionPlan>, consumer_task_count: usize) -> Self

pub fn input_partition_count(&self) -> usize

pub fn consumer_task_count(&self) -> usize

Trait Implementations

impl Debug for BroadcastExec

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

Formats the value using the given formatter.

impl DisplayAs for BroadcastExec

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 BroadcastExec

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 schema(&self) -> SchemaRef

Get the schema for this execution plan

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 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 metrics(&self) -> Option<MetricsSet>

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

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.