Struct UnionExec 

pub struct UnionExec {
    inputs: Vec<Arc<dyn ExecutionPlan>>,
    metrics: ExecutionPlanMetricsSet,
    cache: PlanProperties,
}

UnionExec: UNION ALL execution plan.

UnionExec combines multiple inputs with the same schema by concatenating the partitions. It does not mix or copy data within or across partitions. Thus if the input partitions are sorted, the output partitions of the union are also sorted.

For example, given a UnionExec of two inputs, with N partitions, and M partitions, there will be N+M output partitions. The first N output partitions are from Input 1 partitions, and then next M output partitions are from Input 2.

                       ▲       ▲           ▲         ▲
                       │       │           │         │
     Output            │  ...  │           │         │
   Partitions          │0      │N-1        │ N       │N+M-1
(passes through   ┌────┴───────┴───────────┴─────────┴───┐
 the N+M input    │              UnionExec               │
  partitions)     │                                      │
                  └──────────────────────────────────────┘
                                     ▲
                                     │
                                     │
      Input           ┌────────┬─────┴────┬──────────┐
    Partitions        │ ...    │          │     ...  │
                   0  │        │ N-1      │ 0        │  M-1
                 ┌────┴────────┴───┐  ┌───┴──────────┴───┐
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │                 │  │                  │
                 │Input 1          │  │Input 2           │
                 └─────────────────┘  └──────────────────┘

Fields

inputs: Vec<Arc<dyn ExecutionPlan>>

metrics: ExecutionPlanMetricsSet

cache: PlanProperties

Implementations

impl UnionExec

pub fn new(inputs: Vec<Arc<dyn ExecutionPlan>>) -> UnionExec

👎Deprecated since 44.0.0: Use UnionExec::try_new instead

Create a new UnionExec

pub fn try_new( inputs: Vec<Arc<dyn ExecutionPlan>>, ) -> Result<Arc<dyn ExecutionPlan>, DataFusionError>

Try to create a new UnionExec.

Errors

Returns an error if:

• inputs is empty

Optimization

If there is only one input, returns that input directly rather than wrapping it in a UnionExec

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

Get inputs of the execution plan

Trait Implementations

impl Clone for UnionExec

fn clone(&self) -> UnionExec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UnionExec

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

Formats the value using the given formatter.

impl DisplayAs for UnionExec

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 UnionExec

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

Return a reference to Any that can be used for downcasting

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

Tries to push projection down through union. If possible, performs the pushdown and returns a new UnionExec as the top plan which has projections as its children. Otherwise, returns None.

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 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 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<UnionExec>, children: 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 metrics(&self) -> Option<MetricsSet>

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

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 supports_limit_pushdown(&self) -> bool

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

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 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 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>, 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 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 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. This method is called as we recurse back up the plan tree after pushing filters down to child nodes via ExecutionPlan::gather_filters_for_pushdown. It allows the current node to process the results of filter pushdown from its children, deciding whether to absorb filters, modify the plan, or pass filters back up to its parent.

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