Struct EmptyExec

pub struct EmptyExec { /* private fields */ }

Execution plan for empty relation with produce_one_row=false

Implementations

impl EmptyExec

pub fn new(schema: Arc<Schema>) -> EmptyExec

Create a new EmptyExec

pub fn with_partitions(self, partitions: usize) -> EmptyExec

Create a new EmptyExec with specified partition number

Trait Implementations

impl Clone for EmptyExec

fn clone(&self) -> EmptyExec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EmptyExec

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

Formats the value using the given formatter.

impl DisplayAs for EmptyExec

fn fmt_as( &self, t: DisplayFormatType, f: &mut Formatter<'_>, ) -> Result<(), Error>

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

impl ExecutionPlan for EmptyExec

fn as_any(&self) -> &(dyn Any + 'static)

Return a reference to Any that can be used for downcasting

fn name(&self) -> &'static str

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

fn properties(&self) -> &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<EmptyExec>, _: Vec<Arc<dyn ExecutionPlan>>, ) -> Result<Arc<dyn ExecutionPlan>, DataFusionError>

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

fn execute( &self, partition: usize, context: Arc<TaskContext>, ) -> Result<Pin<Box<dyn RecordBatchStream<Item = Result<RecordBatch, DataFusionError>> + Send>>, DataFusionError>

Begin execution of partition, returning a Stream of RecordBatches.

fn statistics(&self) -> Result<Statistics, DataFusionError>

👎Deprecated since 48.0.0: Use partition_statistics method instead

Returns statistics for this ExecutionPlan node. If statistics are not available, should return Statistics::new_unknown (the default), not an error.

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 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<LexRequirement>>

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 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 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, 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, child_pushdown_result: ChildPushdownResult, _config: &ConfigOptions, ) -> Result<FilterPushdownPropagation<Arc<dyn ExecutionPlan>>, DataFusionError>

Handle the result of a child pushdown. This is called as we recurse back up the plan tree after recursing down and calling ExecutionPlan::gather_filters_for_pushdown. Once we know what the result of pushing down filters into children is we ask the current node what it wants to do with that result. For a DataSourceExec that may be absorbing the filters to apply them during the scan phase (also known as late materialization). A FilterExec may absorb any filters its children could not absorb, or if there are no filters left it may remove itself from the plan altogether. It combines both ChildPushdownResult::parent_filters and ChildPushdownResult::self_filters into a single predicate and replaces it’s own predicate. Then it passes PredicateSupport::Supported for each parent predicate to the parent. A HashJoinExec may ignore the pushdown result since it needs to apply the filters as part of the join anyhow. It passes ChildPushdownResult::parent_filters back up to it’s parents wrapped in FilterPushdownPropagation::transparent and ChildPushdownResult::self_filters is discarded.