Struct BufferExec 

pub struct BufferExec { /* private fields */ }

WARNING: EXPERIMENTAL

Decouples production and consumption of record batches with an internal queue per partition, eagerly filling up the capacity of the queues even before any message is requested.

            ┌───────────────────────────┐
            │        BufferExec         │
            │                           │
            │┌────── Partition 0 ──────┐│
            ││            ┌────┐ ┌────┐││       ┌────┐
──background poll────────▶│    │ │    ├┼┼───────▶    │
            ││            └────┘ └────┘││       └────┘
            │└─────────────────────────┘│
            │┌────── Partition 1 ──────┐│
            ││     ┌────┐ ┌────┐ ┌────┐││       ┌────┐
──background poll─▶│    │ │    │ │    ├┼┼───────▶    │
            ││     └────┘ └────┘ └────┘││       └────┘
            │└─────────────────────────┘│
            │                           │
            │           ...             │
            │                           │
            │┌────── Partition N ──────┐│
            ││                   ┌────┐││       ┌────┐
──background poll───────────────▶│    ├┼┼───────▶    │
            ││                   └────┘││       └────┘
            │└─────────────────────────┘│
            └───────────────────────────┘

The capacity is provided in bytes, and for each buffered record batch it will take into account the size reported by RecordBatch::get_array_memory_size.

If a single record batch exceeds the maximum capacity set in the capacity argument, it’s still allowed to pass in order to not deadlock the buffer.

This is useful for operators that conditionally start polling one of their children only after other child has finished, allowing to perform some early work and accumulating batches in memory so that they can be served immediately when requested.

Implementations

impl BufferExec

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

Builds a new BufferExec with the provided capacity in bytes.

pub fn input(&self) -> &Arc<dyn ExecutionPlan>

Returns the input ExecutionPlan of this BufferExec.

pub fn capacity(&self) -> usize

Returns the per-partition capacity in bytes for this BufferExec.

Trait Implementations

impl Clone for BufferExec

fn clone(&self) -> BufferExec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BufferExec

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

Formats the value using the given formatter.

impl DisplayAs for BufferExec

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 BufferExec

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

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 cardinality_effect(&self) -> CardinalityEffect

Gets the effect on cardinality, if known

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

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>

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>>>

Handle the result of a child pushdown.

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

Try to push down sort ordering requirements to this node.

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) -> SchemaRef

Get the schema for this execution plan

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

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

Reset any internal state within this ExecutionPlan.

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

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

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

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